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PubMed1996

The Quebec Task Force classification for Spinal Disorders and the severity, treatment, and outcomes of sciatica and lumbar spinal stenosis.

STUDY DESIGN: A prospective cohort study of patients in Maine with sciatica and lumbar spinal stenosis treated surgically and nonsurgically. SUMMARY OF BACKGROUND DATA: In 1987, the Quebec Task Force on Spinal Disorders proposed a diagnostic classification to help make clinical decisions, evaluate quality of care, assess prognosis, and conduct research. OBJECTIVES: To assess the Quebec Task Force classification's ability to stratify patients according to severity and treatment at baseline, and to assess changes over time in health-related quality of life, including symptoms, functional status, and disability. METHODS: Five hundred sixteen patients participating in the Maine Lumbar Spine Study who completed baseline and 1-year follow-up evaluations were classified successfully according to the Quebec Task Force classification. Patient characteristics and treatments were compared across Quebec Task Force classification categories. Changes in health-related quality of life over 1 year were assessed according to Quebec Task Force classification category and type of treatment. RESULTS: Among patients with sciatica (n = 370), higher Quebec Task Force classification categories (from 2, pain radiating to the proximal extremity, to 6, sciatica with evidence of nerve root compression) were associated with increased severity of symptoms at baseline. There was no association between Quebec Task Force classification and baseline functional status. Quebec Task Force classification was associated strongly with the likelihood of receiving surgical treatment (P < or = 0.005). Among patients with sciatica treated nonsurgically, improvement at 1 year in back-specific and generic physical function increased with higher Quebec Task Force classification category (P < or = 0.05). Only a nonsignificant trend was observed for surgically treated patients. Patients with lumbar spinal stenosis (Quebec Task Force classification 7, n = 131) had baseline features and outcomes distinct from patients with sciatica. CONCLUSIONS: For patients with sciatica, the Quebec Task Force classification was highly associated with the severity of symptoms and the probability of subsequent surgical treatment. Nonsurgically treated patients in Quebec Task Force classification categories reflecting nerve root compression had greater improvement than those with pain symptoms alone. Among surgical patients, the Quebec Task Force classification was not associated with outcome. These results provide validation for the classification and its wider adoption. Nonetheless, improved diagnostic classifications are needed to predict outcomes better in patients with sciatica who undergo surgery.

Adolescent↗

PubMed1979

A critical analysis of the classifications of non-Hodgkin's lymphomas.

The Rappaport classification of non-Hodgkin's lymphomas was proposed almost a quarter century ago, before the advent of modern immunology. This classification, which is based entirely on morphologic features, has proved its clinical usefulness. In light of recent scientific advances, however, its terminology is not appropriate. Five new classifications have been proposed recently, each claiming to have more merit than the others. The purpose of this study is to critically analyze and evaluate these newly proposed classifications to determine which classification is conceptually and scientifically acceptable as well as clinically useful. The results of the study show that there are more similarities than differences among the Rappaport. Lukes and Collins, Dorfman, British, and WHO classifications; the Kiel classification, however, is fundamentally different (Tables 8, 9, 11). None of these classifications can be used in its proposed form. Based on the analysis of these classifications, a compromise working classification is proposed which incorporates the relevant concepts and terminology from the Rappaport, Berard, Dorfman, WHO, and Lukes and Collins classifications (Tables 15, 16). The proposed compromise classification is an attempt to reconcile the various classifications, and to stimulate others to offer modifications which may bring about a final solution to the problem of classification of non-Hodgkin's lymphomas.

Burkitt Lymphoma↗

PubMed2002

A comparison of different biogeographical classifications of Europe, Great Britain and Spain.

Various biogeographical and bioclimatic classifications of a number of regions, countries and continents have been created to meet different objectives. A policy maker might ask the question 'why is there no single accepted classification and how do the different classifications compare with one another?' In order to answer these two questions three classifications created by different methods for Great Britain and two for Spain are compared using the Kappa statistic. All of the classifications were created from data on cellular grids with a set window size. Further non-statistical comparisons are made with other classifications. The biogeographic classifications studied in this paper produced three different types of zone: those that were always identified whatever the method; those that were broadly similar but where the boundaries differed; and those that were unique to a particular classification. These different types of zone are likely to exist for any comparison between classifications of a particular region. The extent of the geographic window from which data were obtained had a major effect on the classification of grid cells at the edges of the window. For example, the few grid cells in the south of England, with characteristics of continental Europe, are not detected if data from Great Britain alone are used for the classification. We conclude that the data window should always be larger than the area for which the classification is being made. The objective Kappa statistic, although useful, was not capable of discerning similarities and dissimilarities that appear obvious to the subjective human eye. Although the details of the classifications differed there were broad similarities between the classifications and these differences reflect important divisions along major environmental axes that have been inferred by earlier biogeographers. As the divisions are real there is a sound basis for their use in future land use or environmental policy.

Climate↗

PubMed1997

Evaluation of UICC TNM classification for pancreatic cancer. A study of 228 patients.

CONCLUSION: A different stage grouping of TNM factors can improve the predictivity of the UICC TNM classification for pancreatic cancer. Nevertheless, the Japanese Pancreas Society (JPS) classification maintains a higher prognostic value. BACKGROUND: The use of a reliable staging classification facilitates the evaluation of anticancer treatments and the correct management of patients. The aim of the present study was to evaluate the prognostic value of three modified UICC TNM classifications, obtained by different stage grouping of the UICC TNM factors, comparing their predictivity to the standard UICC and the JPS classifications. METHODS: Clinical material consisted of 228 patients who underwent resection for pancreatic cancer. The reliability of the classifications was analyzed by the following methods: univariate analysis of stage survival curves; multivariate analysis of each classification after adjusting for grading and radicality; and correlation between the patients' distribution in the stages of each classification and in survival classes. RESULTS: The following modified UICC classification allowed a better differentiation of stage II and III survival (P = 0.08) than standard UICC (P = 0.74): stage I: T1N0M0; stage II: T1N1M0/T2N0M0: stage III: T2N1M0/T3 any NM0; stage IV: M1. The JPS classification better discriminated between the different stages (P < 0.001). All classifications had an independent prognostic value by multivariate analysis. The correlation between stages and survival classes was higher for the JPS classification than either UICC TNM classification or the modified UICC classifications.

Adenocarcinoma↗

PubMed1999

EORTC classification for primary cutaneous lymphomas: the best guide to good clinical management. European Organization for Research and Treatment of Cancer.

In 1997 the Cutaneous Lymphoma Study Group of the European Organization for Research and Treatment of Cancer (EORTC) published a proposal for a classification for the group of primary cutaneous lymphomas (1). The EORTC classification is the first and only classification that is designed exclusively for the group of primary cutaneous lymphomas. It is also the only classification that has been clinically validated for this group of diseases. As illustrated by this special issue, this classification has resulted not only in the discussion of the definition and terminology of some types of cutaneous T-cell lymphoma (CTCL) and cutaneous B-cell lymphoma (CBCL), but also in a discussion of whether organ-based classification schemes (separate from existing hematopathologic classification schemes for non-Hodgkin lymphomas) should be used. This article explains why it was necessary to create a separate classification for the group of primary cutaneous lymphomas. A short introduction on the history of the classification of cutaneous lymphomas is provided. Next, the basic principles of the EORTC classification are presented. Finally, controversies between the EORTC classification versus the REAL classification (2) and the proposed WHO classification (3), which still impede the usage of one common classification system, are discussed.

Humans↗

PubMed2003

Comparison of reliability between the Lenke and King classification systems for adolescent idiopathic scoliosis using radiographs that were not premeasured.

STUDY DESIGN: Multisurgeon comparison of two radiographic scoliosis curve classification systems was performed. OBJECTIVE: To determine the reliability of the King and Lenke classifications systems for adolescent idiopathic scoliosis using radiographs that had not been premeasured. SUMMARY OF BACKGROUND DATA: Recent studies introducing the new Lenke classification system for idiopathic scoliosis have reported reliability improved over that of the King classification system. This newer classification system evaluates three different parameters (curve type, lumbar modifier, and sagittal thoracic modifier) and then combines them. The reliability of both classification systems had been determined using radiographs in which all of the curves had been premeasured (recorded on the radiographs) before review by examiners. However, in a normal clinical situation, spine surgeons need to determine the Cobb angles independently, thus introducing another variable. METHODS: On two separate occasions, four orthopedic surgeons independently evaluated preoperative radiographs (standing posteroanterior, lateral, and two supine side-bending views) of 50 patients with adolescent idiopathic scoliosis. All measurements had been removed on every radiograph before each evaluation. The results were determined by calculating the average percentage of intraobserver and interobserver agreement. Reliability was quantified using kappa statistics. RESULTS: The King classification demonstrated good intraobserver and fair interobserver reliability. Intraobserver percentage of agreement averaged 83.5% (kappa coefficient, 0.81). Interobserver percentage of agreement averaged 68.0% (kappa coefficient, 0.61). All three parameters of the overall Lenke curve classification demonstrated fair reliability. Intraobserver percentage of agreement averaged 65.0% (kappa coefficient, 0.60). Interobserver percentage of agreement averaged 55.5% (kappa coefficient, 0.50). When the Lenke curve type was examined separately, intraobserver percentage of agreement averaged 81.5% (kappa coefficient, 0.76) and interobserver percentage of agreement averaged 71.5% (kappa coefficient, 0.64). The results for this variable (curve type) were similar to those for the King classification. For the Lenke lumbar modifier, the percentage of agreement and reliability were excellent. For the sagittal thoracic modifier, the percentage of agreement was good, but the kappa values were low because of an extreme imbalance in the grouping of hypokyphotic, normal, and hyperkyphotic spines. CONCLUSIONS: In this study, with each investigator performing the radiographic measurements, the King classification was found to be better than had been reported recently. The Lenke classification system for adolescent idiopathic scoliosis was found to be less reliable than previously reported when the radiographs were premeasured. This was particularly true when all three parameters of this new classification system were combined. This difference in reliability of the Lenke classification between studies can be attributed to the additional variable of determining the Cobb measurements on each of the unmarked radiographs. Although this new classification system has limitations with respect to interobserver and intraobserver reliability, for planning operative treatment, it offers a more comprehensive radiographic evaluation of patients with adolescent idiopathic scoliosis than previous systems.

Adolescent↗

PubMed1999

Development of a classification system for periodontal diseases and conditions.

Classification systems are necessary in order to provide a framework in which to scientifically study the etiology, pathogenesis, and treatment of diseases in an orderly fashion. In addition, such systems give clinicians a way to organize the health care needs of their patients. The last time scientists and clinicians in the field of periodontology and related areas agreed upon a classification system for periodontal diseases was in 1989 at the World Workshop in Clinical Periodontics. Subsequently, a simpler classification was agreed upon at the 1st European Workshop in Periodontology. These classification systems have been widely used by clinicians and research scientists throughout the world. Unfortunately, the 1989 classification had many shortcomings including: 1) considerable overlap in disease categories, 2) absence of a gingival disease component, 3) inappropriate emphasis on age of onset of disease and rates of progression, and 4) inadequate or unclear classification criteria. The 1993 European classification lacked the detail necessary for adequate characterization of the broad spectrum of periodontal diseases encountered in clinical practice. The need for a revised classification system for periodontal diseases was emphasized during the 1996 World Workshop in Periodontics. In 1997 the American Academy of Periodontology responded to this need and formed a committee to plan and organize an international workshop to revise the classification system for periodontal diseases. The proceedings in this volume are the result of this reclassification effort. The process involved development by the Organizing Committee of an outline for a new classification and identification of individuals to write state-of-the-science reviews for each of the items on the outline. The reviewers were encouraged to depart from the preliminary outline if there were data to support any modifications. On October 30-November 2, 1999, the International Workshop for a Classification of Periodontal Diseases and Conditions was held and a new classification was agreed upon (Fig. 1). This paper summarizes how the new classification for periodontal diseases and conditions presented in this volume differs from the classification system developed at the 1989 World Workshop in Clinical Periodontics. In addition, an analysis of the rationale is provided for each of the modifications and changes.

Humans↗

PubMedDate not supplied

Development of a classification system for periodontal diseases and conditions.

Classification systems are necessary in order to provide a framework in which to scientifically study the etiology, pathogenesis, and treatment of diseases in an orderly fashion. In addition, such systems give clinicians a way to organize the health care needs of their patients. The last time scientists and clinicians in the field of periodontology and related areas agreed upon a classification system for periodontal diseases was in 1989 at the World Workshop in Clinical Periodontics. Subsequently, a simpler classification was agreed upon at the 1st European Workshop in Periodontology. These classification systems have been widely used by clinicians and research scientists throughout the world. Unfortunately, the 1989 classification had many shortcomings, including: (1) considerable overlap in disease categories, (2) absence of a gingival disease component, (3) inappropriate emphasis on age of onset of disease and rates of progression, and (4) inadequate or unclear classification criteria. The 1993 European classification lacked the detail necessary for adequate characterization of the broad spectrum of periodontal diseases encountered in clinical practice. The need for a revised classification system for periodontal diseases was emphasized during the 1996 World Workshop in Periodontics. In 1997 the American Academy of Periodontology responded to this need and formed a committee to plan and organize an international workshop to revise the classification system for periodontal diseases. The proceedings in this volume are the result of this reclassification effort. The process involved development by the Organizing Committee of an outline for a new classification and identification of individuals to write state-of-the-science reviews for each of the items on the outline. The reviewers were encouraged to depart from the preliminary outline if there were data to support any modifications. On October 30-November 2, 1999, the International Workshop for a Classification of Periodontal Diseases and Conditions was held and a new classification was agreed upon (Figure 1). This paper summarizes how the new classification for periodontal diseases and conditions presented in this volume differs from the classification system developed at the 1989 World Workshop in Clinical Periodontics. In addition, an analysis of the rationale is provided for each of the modifications and changes.

Adolescent↗

PubMed1991

Allocation of patients to paucibacillary or multibacillary drug regimens for the treatment of leprosy--a comparison of methods based mainly on skin smears as opposed to clinical methods--alternative clinical methods for classification of patients.

This paper reports on the experience with classification of patients at the All-Africa Leprosy and Rehabilitation Training Centre (ALERT) in the Shoa Province in Ethiopia. Classification on clinical grounds is compared with classification which is primarily based on the result of skin-smear examinations. In addition, possible alternative clinical methods for the allocation of patients to the multidrug therapy (MDT) regimens are discussed. The analysis includes 1525 new patients. In 730 patients classified clinically as paucibacillary (PB), this classification was not confirmed by skin-smear results in only 1.5%; whereas in 795 patients classified clinically as multibacillary (MB), the classification was not confirmed in 21.1%. Possible reasons, notably for the latter discrepancy, are discussed. Based on an assessment of the correctness of the diagnosis and the most probable classification, it was found that if classification had been based on the skin-smear results, 9.3% of the 795 patients classified as MB would have been classified incorrectly as PB. Classification based on clinical signs resulted in incorrect classification, MB instead of PB, of 8.7% of the 795 patients. Over-classification of MB patients, which was found to be supervisor related, is open to improvement by a strict application of clinical criteria for classification. The experience in the ALERT leprosy control program shows that classification which is based on clinical signs may, in particular, result in some PB patients being classified as MB, while classification based on the results of skin-smear examinations is more likely to result in some MB patients being classified as PB. It was concluded that, provided a number of requirements aimed at limiting the number of misclassified patients are introduced, patients can be classified based on clinical signs and, hence, in the absence of skin-smear services for routine classification purposes.

Drug Therapy, Combination↗

PubMed2005

Which classification for ethmoid malignant tumors involving the anterior skull base?

BACKGROUND: The purpose of this study was to compare three systems of classification for malignant ethmoidal tumors in patients undergoing anterior craniofacial resection. METHODS: A radiologic locoregional evaluation of 241 patients with malignant ethmoid tumors was performed before patients underwent an anterior craniofacial resection. Disease in each case was staged according to the American Joint Committee on Cancer-Union Internationale Contre le Cancer (AJCC-UICC) 1997 classification, the AJCC-UICC 2002 classification, and the Istituto Nazionale Tumori (INT) classification. Kaplan-Meier curves and Cox models were used to investigate the prognostic value of each classification system on disease-free survival (DFS) and overall survival (OS). The classifications were compared in terms of prognostic discrimination capability, measured by use of an index of agreement between each classification and DFS or OS time. RESULTS: All three classification systems yielded statistically significant results in the Cox analysis, both for DFS and OS. In the AJCC-UICC 2002 system, minor differences were observed between T1 and T3 tumors. The INT classification showed a progressive worsening of the prognosis with increasing stage. The index of prognostic discrimination favored the INT classification over both the 1997 and 2002 AJCC-UICC classifications. CONCLUSIONS: Both the 1997 and 2002 AJCC-UICC classifications seemed to have limited prognostic value. By contrast, the INT classification satisfied one of the main goals of tumor staging, demonstrating the progressive worsening of prognosis with different tumor classes.

Adolescent↗

PubMed2005

A proposal of the modified liver damage classification for hepatocellular carcinoma.

OBJECTIVE: The purpose of this study was to evaluate the validity of the two common classifications for assessing liver function; the Child-Pugh classification and the liver damage classification. We also examined the feasibility of the modified liver damage classification. METHODS: A total of 2306 HCC patients diagnosed between 1990 and 2002 were categorized according to the three classifications. The modified liver damage classification is calculated by summation of the scores for five variables (serum bilirubin level, serum albumin level, prothrombin activity, ICG retention rate at 15min, ascites) of the liver damage classification and classified patients into grades A-C in the similar manner as the Child-Pugh classification. The differences in distribution and survival rate of the patients in each group were compared. RESULTS: With respect to the patient distribution, 1787 (77.5%) and 469 (20.3%) patients were categorized into Child-Pugh grades A and B, respectively, whereas 1187 (51.5%) and 962 (41.7%) patients were categorized into liver damage grades A and B, respectively. As a result of this disproportionate distribution, survival rates of Child-Pugh grades A and B were lower than those of the liver damage grades A and B. Furthermore, some discrepancies were found in the distribution of patients between the liver damage classification and the modified liver damage classification. One hundred and forty-one patients of the 1187 liver damage grade A patients were categorized into grade B by the modified liver damage classification and 71 patients of the 962 liver damage grade B patients were categorized into grade C by the modified liver damage classification. The survival rates of these subgroups were similar to those of the liver damage grades B and C, respectively. CONCLUSION: The modified liver damage classification appears to be the best available tool for assessing residual liver function, for estimating the survival of Japanese HCC patients and for making decisions concerning the treatment of these patients.

Journal Article↗

PubMed2004

Survival of patients with nonseminomatous germ cell cancer: a review of the IGCC classification by Cox regression and recursive partitioning.

The International Germ Cell Consensus (IGCC) classification identifies good, intermediate and poor prognosis groups among patients with metastatic nonseminomatous germ cell tumours (NSGCT). It uses the risk factors primary site, presence of nonpulmonary visceral metastases and tumour markers alpha-fetoprotein (AFP), human chorionic gonadotrophin (HCG) and lactic dehydrogenase (LDH). The IGCC classification is easy to use and remember, but lacks flexibility. We aimed to examine the extent of any loss in discrimination within the IGCC classification in comparison with alternative modelling by formal weighing of the risk factors. We analysed survival of 3048 NSGCT patients with Cox regression and recursive partitioning for alternative classifications. Good, intermediate and poor prognosis groups were based on predicted 5-year survival. Classifications were further refined by subgrouping within the poor prognosis group. Performance was measured primarily by a bootstrap corrected c-statistic to indicate discriminative ability for future patients. The weights of the risk factors in the alternative classifications differed slightly from the implicit weights in the IGCC classification. Discriminative ability, however, did not increase clearly (IGCC classification, c=0.732; Cox classification, c=0.730; Recursive partitioning classification, c=0.709). Three subgroups could be identified within the poor prognosis groups, resulting in classifications with five prognostic groups and slightly better discriminative ability (c=0.740). In conclusion, the IGCC classification in three prognostic groups is largely supported by Cox regression and recursive partitioning. Cox regression was the most promising tool to define a more refined classification. British Journal of Cancer (2004) 90, 1176-1183. doi:10.1038/sj.bjc.6601665 www.bjcancer.com Published online 24 February 2004

Biomarkers, Tumor↗

PubMed2001

A prospective comparison between two seizure classifications.

The International Classification of Epileptic Seizures is the most widely used, but an alternative system based purely on ictal symptoms and signs has been proposed: the semiological classification. Our objective was to compare the two in a sample of patients evaluated at epilepsy centers. We collected 78 consecutive patients evaluated in outpatient epilepsy clinics who subsequently underwent noninvasive video-EEG monitoring at three centers. Patients with pseudoseizures were excluded. Seizures were first classified based on information obtained during clinic visits, and again after video-EEG monitoring. Each time, seizures were classified using both the International Classification and the semiological classification. Eventual epilepsy syndrome diagnosis was based on all the clinical data, video-EEG monitoring, and other independent tests including imaging studies. Sixty-six (87%) patients were classified as having 'complex partial seizures' in the International Classification. Using the semiological classification, these same 66 patients were classified as follows: automotor (34), dialeptic (17), hypermotor (13), hypomotor (2). Seizure classification changed between initial 'clinic-based' data and the 'monitoring-based' classification in 27 cases using the ILAE, vs. six using the semiological classification. Seizure classification tended to change significantly between pre- and post-monitoring using the ILAE but not the semiological classification. The term complex partial seizure included multiple categories of the semiological classification, and was very nonspecific. The semiological classification may be better suited for everyday clinic use, since it is based solely on clinical characteristics.

Electroencephalography↗

PubMed1983

[Classification of schizophrenic psychoses].

There is a substantial need, based on the heuristic principle, to arrive at a valid classification of schizophrenic psychoses. According to the modern theory of science bases on critical rationalism, nosological classifications in psychiatry are regarded as "useful" conventions requiring precise operational definitions. There are several methods of classification, typological classifications having gained widest acceptance in nosology. The multiaxial classification approach allows to document separately data from different levels of data collection, such as symptomatological, etiological, psychosocial and family data, as well as personality factors. However, it is always necessary to render any classification empirically valid by verifying it by means of empirically observed data. In this review, some frequently used classifications of schizophrenic psychoses are evaluated regarding their "usefulness". Usefulness of a classification is assumed if its sub-grouping of data on one level of data collection is validated by data from another level, or if there is sufficient evidence that this classification can generate hypotheses which lend themselves to empirical testing. The traditional sub-classification of schizophrenias into hebephrenic, paranoid, catatonic, and simple forms lacks clear rules for allocating patients to one of the sub-groups; moreover, these sub-groups have not proved reliable. Some authors have tried to classify schizophrenic psychoses via the course of the illness. Methodological difficulties are considerable, and hence most of these classification still await validation. On the other hand, the course of premorbid personality development has been shown to be very important for the sub-grouping of schizophrenics: Good vs. poor premorbid adaptation dichotomy has been validated by prognostic and psychophysiological studies, by therapy response and by family data. Any distinction between acute and chronic types is bound to be of rather questionable value. Symptom criteria have also been proposed for differentiating between schizophrenic psychoses. Paranoid vs. nonparanoid dichotomy has been supported by several biochemical, psychophysiological, familial and therapy response studies. There is a great deal of evidence from prognostic and genetic studies that the presence of a valid sub-group of schizophrenic psychoses. Sub-grouping schizophrenics according to narrowly defined symptom criteria such as Schneider's first-rank symptoms and Langfeldt's, Feighner's and Spitzer's research symptom criteria is of limited value for a valid sub-classification. An approach to classification based on the distinction between the predominance of positive vs. negative schizophrenic symptomatology is of heuristic usefulness in that it generates biochemical and pathophysiological hypotheses which can be tested empirically.

Acute Disease↗

PubMed2004

Tumor classification: molecular analysis meets Aristotle.

BACKGROUND: Traditionally, tumors have been classified by their morphologic appearances. Unfortunately, tumors with similar histologic features often follow different clinical courses or respond differently to chemotherapy. Limitations in the clinical utility of morphology-based tumor classifications have prompted a search for a new tumor classification based on molecular analysis. Gene expression array data and proteomic data from tumor samples will provide complex data that is unobtainable from morphologic examination alone. The growing question facing cancer researchers is, "How can we successfully integrate the molecular, morphologic and clinical characteristics of human cancer to produce a helpful tumor classification?" DISCUSSION: Current efforts to classify cancers based on molecular features ignore lessons learned from millennia of experience in biological classification. A tumor classification must include every type of tumor and must provide a unique place for each tumor within the classification. Groups within a classification inherit the properties of their ancestors and impart properties to their descendants. A classification was prepared grouping tumors according to their histogenetic development. The classification is simple (reducing the complexity of information received from the molecular analysis of tumors), comprehensive (providing a place for every tumor of man), and consistent with recent attempts to characterize tumors by cytogenetic and molecular features. The clinical and research value of this historical approach to tumor classification is discussed. SUMMARY: This manuscript reviews tumor classification and provides a new and comprehensive classification for neoplasia that preserves traditional nomenclature while incorporating information derived from the molecular analysis of tumors. The classification is provided as an open access XML document that can be used by cancer researchers to relate tumor classes with heterogeneous experimental and clinical tumor databases.

Germinoma↗

PubMed1995

A new data model for biological classification.

In the domain of biological classification, classifications are performed hierarchically. There are no standard classifications which are unanimously accepted by the community of each domain; many different interacting views of classification exist about the same data, and the discovery of new data results in changes to the existing classification. Even a single individual may change his or her own classification of a particular group. Since multiple classification views interact, they are semantically related. It is difficult to model this kind of dynamically evolving and semantically interacting classification system using traditional data models, which lack the structural flexibility necessary to support dynamic views of hierarchic classifications, and cannot properly capture the history of these complex interactions. We have developed a new data model which is suitable for supporting semantically interacting dynamic views of hierarchic biological classifications. On the basis of our new data model we have developed a prototype database system called HICLAS (HIerarchical CLAssification System); its domain is plant taxonomy. HICLAS is available through the Internet and an X-window interface has been implemented to support queries to classification data.

Classification↗

PubMed1995

Evaluation of partial classification algorithms using ROC curves.

When using computer programs for decision support in clinical routine, an assessment or a comparison of the underlying classification algorithms is essential. In classical (forced) classification, the classification rule always selects exactly one alternative. A number of proven discriminant measures are available here, e.g.sensitivity and error rate. For probabilistic classification, a series of additional measures has been developed [1]. However, for many clinical applications, there are models where an observation is classified into several classes (partial classification), e.g., models from artificial intelligence, decision analysis, or fuzzy set theory. In partial classification, the discriminatory ability (Murphy) can be adjusted a priori to any level, in most practical cases. Here the usual measures do not apply. We investigate the preconditions for assessment and comparison based on medical decision theory. We focus on problems in the medical domain and establish a methodological framework. When using partial classification procedures, a ROC analysis in the classical sense is no longer appropriate. In forced classification for two classes, the problem is to find a cutoff point on the ROC curve; while in partial classification, you have to find two of them. They characterize the elements being classified as coming from both classes. This extends to several classes. We propose measures corresponding to the usual discriminant measures for forced classification (e.g., sensitivity and error rate) and demonstrate the effects using the ROC approach. For this purpose, we extend the existing method for forced classification in a mathematically sound manner. Algorithms for the construction of thresholds can easily be adapted. Two specific measurement models, based on parametric and non-parametric approaches, will be introduced. The basic methodology is suitable for all partial classification problems, whereas the extended ROC analysis assumes a rank order of the selected alternatives. The method is based on the black box principle and makes use only of the results of the compared algorithms and some general intuitive principles. Therefore, algorithms arising from different "philosophical" approaches may also be compared according to their results. For demonstration purposes, a clinical example from cranial computed tomography is presented. Linear discriminant analysis as a reference is compared to a Bayesian and a fuzzy procedure.

Algorithms↗

PubMed2001

Review of histological classifications of gastrointestinal epithelial neoplasia: differences in diagnosis of early carcinomas between Japanese and Western pathologists.

Gastrointestinal lesions considered to be high-grade adenoma/dysplasia by Western pathologists using the conventional Western classification are often diagnosed as carcinoma by Japanese pathologists using the Japanese group classification. To overcome these differences, the Padova classification, the Vienna classification, and a revision of the Vienna classification have recently been proposed. The clinical usefulness of these five classifications needs to be reviewed for early gastric, esophageal, and colorectal neoplasias. In 1998, 31 pathologists from 12 countries individually diagnosed the same 35 gastric, 21 esophageal, and 20 colorectal specimens. Their histological diagnoses can be classified conventionally and according to the newly proposed terminology, and from these data, the extent of agreement between pathologists with Western and Japanese viewpoints can be calculated, using kappa statistics. With the conventional Western, Japanese, Padova, Vienna, and revised classifications, the agreement scores were 37%, 37%, 71%, 71%, and 80%, respectively, for gastric lesions; 14%, 14%, 57%, 62%, and 67% for esophageal lesions; and 45%, 50%, 65%, 65%, and 70% for colorectal lesions. The kappa values were lower than 0.3 with the conventional Western and Japanese classifications, but higher than 0.5 for gastric lesions, higher than 0.3 for esophageal lesions, and higher than 0.4 for colorectal lesions with the newly proposed classifications. When the literature regarding treatment indications for early neoplastic lesions is reviewed, it becomes apparent that the categories of the revised classification would fit best with current clinical treatment considerations. This classification would be particularly useful for endoscopically resected specimens, to determine whether additional surgery with lymph node dissection is required. In conclusion, the use of the newly proposed terminology can, in large part, resolve the intercountry differences in the diagnosis of adenoma/dysplasia and early carcinoma. However, the newly proposed classifications should be used with caution for biopsy specimens, as sampling error may result in an underestimation of the neoplastic grade or depth of invasion. For the choice between endoscopic and surgical treatment, assessment of the depth of invasion by endoscopic inspection and ultrasound or radiography is essential.

Adenoma↗