Biomedical subjects

Ettore Marubini

Publications and source records attributed to Ettore Marubini.

At least 19 recordsLinked to original sources

PubMed2006

Axillary lymph node nanometastases are prognostic factors for disease-free survival and metastatic relapse in breast cancer patients.

PURPOSE: Early breast cancer presents with a remarkable heterogeneity of outcomes. Undetected, microscopic lymph node tumor deposits may account for a significant fraction of this prognostic diversity. Thus, we systematically evaluated the presence of lymph node tumor cell deposits<or=0.2 mm in diameter [pN0(i+), nanometastases] and analyzed their prognostic effect. EXPERIMENTAL DESIGN: Single-institution, consecutive patients with 8 years of median follow-up (n=702) were studied. To maximize chances of detecting micrometastases and nanometastases, whole-axilla dissections were analyzed. pN0 cases (n=377) were systematically reevaluated by lymph node (n=6676) step-sectioning and anticytokeratin immunohistochemical analysis. The risk of first adverse events and of distant relapse of bona fide pN0 patients was compared with that of pN0(i+), pN1mi, and pN1 cases. RESULTS: Minimal lymph node deposits were revealed in 13% of pN0 patients. The hazard ratio for all adverse events of pN0(i+) versus pN0(i-) was 2.51 (P=0.00019). Hazards of pN1mi and pN0(i+) cases were not significantly different. A multivariate Cox model showed a hazard ratio of 2.16 for grouped pN0(i+)/pN1mi versus pN0(i-) (P=0.0005). Crude cumulative incidence curves for metastatic relapse were also significantly different (Gray's test chi2=5.54, P=0.019). CONCLUSION: Nanometastases are a strong risk factor for disease-free survival and for metastatic relapse. These findings support the inclusion of procedures for nanometastasis detection in tumor-node-metastasis staging.

Adult↗

PubMed2006

EQUAL-quant: an international external quality assessment scheme for real-time PCR.

BACKGROUND: Quantitative gene expression analysis by real-time PCR is important in several diagnostic areas, such as the detection of minimum residual disease in leukemia and the prognostic assessment of cancer patients. To address quality assurance in this technically challenging area, the European Union (EU) has funded the EQUAL project to develop methodologic external quality assessment (EQA) relevant to diagnostic and research laboratories among the EU member states. We report here the results of the EQUAL-quant program, which assesses standards in the use of TaqMan probes, one of the most widely used assays in the implementation of real-time PCR. METHODS: The EQUAL-quant reagent set was developed to assess the technical execution of a standard TaqMan assay, including RNA extraction, reverse transcription, and real-time PCR quantification of target DNA copy number. RESULTS: The multidisciplinary EQA scheme included 137 participating laboratories from 29 countries. We demonstrated significant differences in performance among laboratories, with 20% of laboratories reporting at least one result lacking in precision and/or accuracy according to the statistical procedures described. No differences in performance were observed for the >10 different testing platforms used by the study participants. CONCLUSIONS: This EQA scheme demonstrated both the requirement and demand for external assessment of technical standards in real-time PCR. The reagent design and the statistical tools developed within this project will provide a benchmark for defining acceptable working standards in this emerging technology.

European Union↗

PubMed2006

Artificial neural network for the joint modelling of discrete cause-specific hazards.

OBJECTIVE: Artificial neural network (ANN) based regression methods have been introduced for modelling censored survival data to account for complex prognostic patterns. In the framework of ANN extensions of generalized linear models for survival data, PLANN is a partial logistic ANN, suitable for smoothed discrete hazard estimation as a function of time and covariates. An extension of PLANN for competing risks analysis (PLANNCR) is now proposed for discrete or grouped survival times, resorting to the multinomial likelihood. METHODS AND MATERIALS: PLANNCR is built by assigning input nodes to the explanatory variables with the time interval treated as an ordinal variable. The logistic function is used as activation for the hidden nodes of the network, whereas the softmax, which corresponds to the canonical link of generalized linear models for polytomous regression, is adopted for multiple output nodes, to provide a smoothed estimation of discrete conditional event probabilities for each event. The Kullback-Leibler distance is used as error function for the target vectors, amounting to half of the deviance of a multinomial logistic regression model. PLANNCR can jointly model non-linear, non-proportional and non-additive effects on cause-specific hazards (CSHs). The degree of smoothing is modulated by the number of hidden nodes and penalization of the error function (weight decay). Model optimisation is achieved by quasi-Newton algorithms, while non-linear cross-validation (NCV) and the Network Information Criterion (NIC) were adopted for model selection. PLANNCR was applied to data on 1793 women with primary invasive breast cancer, histologically N-, who underwent surgery at the Milan Cancer Institute between 1981 and 1986. RESULTS: Differential effects of covariates and time on the shape of the CSH for the three main failure causes, namely intra-breast tumor recurrences, distant metastases and contralateral breast cancer, have been enlightened. CONCLUSIONS: PLANNCR can be suitably adopted in an exploratory framework for a thorough evaluation of the disease dynamics in the presence of competing risks.

Adult↗

PubMed2006

Molecular subtyping of breast cancer from traditional tumor marker profiles using parallel clustering methods.

PURPOSE: Recent small-sized genomic studies on the identification of breast cancer bioprofiles have led to profoundly dishomogenous results. Thus, we sought to identify distinct tumor profiles with possible clinical relevance based on clusters of immunohistochemical molecular markers measured on a large, single institution, case series. EXPERIMENTAL DESIGN: Tumor biological profiles were explored on 633 archival tissue samples analyzed by immunohistochemistry. Five validated markers were considered, i.e., estrogen receptors (ER), progesterone receptors (PR), Ki-67/MIB1 as a proliferation marker, HER2/NEU, and p53 in their original scale of measurement. The results obtained were analyzed by three different clustering algorithms. Four different indices were then used to select the different profiles (number of clusters). RESULTS: The best classification was obtained creating four clusters. Notably, three clusters were identified according to low, intermediate, and high ER/PR levels. A further subdivision in two biologically distinct subtypes was determined by the presence/absence of HER2/NEU and of p53. As expected, the cluster with high ER/PR levels was characterized by a much better prognosis and response to hormone therapy compared to that with the lowest ER/PR values. Notably, the cluster characterized by high HER2/NEU levels showed intermediate prognosis, but a rather poor response to hormone therapy. CONCLUSIONS: Our results show the possibility of profiling breast cancers by means of traditional markers, and have novel clinical implications on the definition of the prognosis of cancer patients. These findings support the existence of a tumor subtype that responds poorly to hormone therapy, characterized by HER2/NEU overexpression.

Adult↗

PubMed2006

Bivariate statistical approach to evaluate laboratory performance by analysis of standard curves in an External Quality Assurance program for quantitative assays based on real-time PCR with Taq-Man probes.

Recently a revolutionary technique for quantitative PCR determination was introduced in diagnostic laboratories. To determine the influence of technical variability on the reliability of the quantitative assay, it is crucial to use External Quality Assurance (EQA) programs. An EQA program was developed in Italy to check the analytical performance of real-time PCR procedures based on Taq-Mantrade mark probes. This article suggests a new statistical approach to discriminate, using a bivariate technique, laboratory performance that appears to be questionable, by separately considering the two main features of the standard curve: analytical sensitivity and efficiency. Furthermore, specific indexes to evaluate the impact of these two features on the determination of the initial number of molecules are given to help to improve the assay procedure.

Chemistry, Clinical↗

PubMed2006

[Statistical notes. Which risks do the patient incur if his own cardiologist accepts to be involved in a clinical trial without deep consideration of the a priori available evidence?].

The aim of this statistical note is to describe the results of the randomized controlled clinical trial TARGET, which compared the effect of tirofiban (new treatment) and abciximab (standard treatment) in patients who were expected to undergo coronary stenting. Primary aim of TARGET was to evaluate the non-inferiority of tirofiban with respect to abciximab, but it concluded in favor of superiority of the standard treatment. The authors of this study point out that a deep consideration regarding a priori available evidence could have avoided to expose 2398 patients randomized to tirofiban to the risk of death or non-fatal myocardial infarction.

Abciximab↗

PubMed2006

[What does "p" mean at conclusion of a test of hypothesis in a randomized controlled clinical trial of superiority?].

The aim of this statistical note, the sixth in the series, is to introduce the rationale of the test of hypothesis suitable for comparing the effect of two treatments in a randomized controlled clinical trial of superiority. The presentation takes advantage of the analogy with a criminal trial debate based upon circumstantial evidence in an Italian Court. The results of three randomized controlled clinical trials: ISIS-1, AIMS and RESTORE are introduced and proper ways for their interpretation are suggested.

Randomized Controlled Trials as Topic↗

PubMed2005

An Italian program of external quality control for quantitative assays based on real-time PCR with Taq-Man probes.

Quantitative real-time PCR techniques are increasingly being used for the measurement of nucleic acids in research applications as well as in the clinical laboratory. It is therefore important that external quality control programs (EQA) are implemented for the evaluation of the analytical aspects common to molecular tests based on quantitative PCR. The aim of this study was the development of an Italian program of external quality control for quantitative assays based on real-time PCR with Taq-Mantrade mark probes to compare the analytical performance of 42 laboratories. Participants were provided with a set of reagents (cDNA for reference curve preparation, primers-probe mix and three unknown samples) and requested to perform a conventional assay using the master mix employed in their laboratories. The quantitative results in unknown samples were analyzed. The results of our study showed clear heterogeneity in performance. Two of the 42 laboratories provided results indicating contamination during the experiment, whereas six did not provide values for at least one of the six standard points. Only 12 laboratories gave results that were both precise and accurate for all the samples tested. Regarding imprecision, 17 laboratories appeared to deviate in at least one result, whereas inaccuracy showed an inverse dose-dependent trend. Finally, 12 laboratories were not able to measure the sample with the lowest concentration. Ten of these laboratories were equipped with the same instruments. The results of this first round of analytical EQA of real-time PCR-based methods seem to indicate high variability among laboratories carrying out the same experimental protocol. These findings could have implications for any assay based on this type of technique. This survey demonstrates the importance of experimental EQAs of methodological proficiency testing. Our approach has proved useful for comparing the analytical aspects shared by all diagnostic laboratories applying quantitative assays for the measurement of nucleic acids based on the use of Taq-Mantrade mark probes and real-time platforms.

Base Sequence↗

PubMed2005

[Statistical notes. Hazard curves of sudden death: their role in the cardiologist's clinical decision].

In long-term studies researchers are mainly concerned with occurrence of death during the follow-up period. This statistical note is focused on survival analysis which is the main tool to process this kind of data. Survival curve, cumulative mortality curve and hazard curve are here introduced together with an appropriate effect indicator: hazard ratio. In particular, the use of the latter is shown by resorting to the randomized controlled clinical trial TARGET.

Cardiology↗

PubMed2005

[Statistical notes. Randomized controlled clinical trials of both superiority and non-inferiority: critical considerations].

The aim of this statistical note, the fourth in the series, is to describe and critically appraise the randomized controlled clinical trial (RCCT) GUSTO V, which combined in a single RCCT both the superiority and non-inferiority hypotheses. In this note we present the logical path that the authors have presumably followed in planning a RCCT of such a kind. The results are reported and possible critical aspects are highlighted and debated upon. Finally the cardiologist reader is stimulated to give his own opinion on this kind of approach.

Algorithms↗

PubMed2004

Soy isoflavones and melatonin for the relief of climacteric symptoms: a multicenter, double-blind, randomized study.

OBJECTIVE: To evaluate the effect of soy isoflavones and melatonin in relieving menopausal symptoms. METHODS: Double-blind, multicenter, randomized trial performed according to a 2 x 2 factorial design. Treatment groups: (1) soy isoflavones+melatonin; (2) soy isoflavones alone; (3) melatonin alone; (4) placebo. 80 mg of soy isoflavones, 3 mg of pure melatonin or placebo were supplemented to participants for 3 months. Severity of menopausal symptoms was recorded at baseline and after 3 months using the Greene Climacteric Scale. RESULTS: 388 consecutive women were screened: not eligible 98, refused informed consent 28. Randomized 262 and analyzed 232; twelve women withdrew because of adverse events. Median percent differences between basal and final scores were 39% in the isoflavones + melatonin group, 38% in the isoflavones alone group, 26% in the melatonin alone group and 38% in the placebo group. Placebo response was much higher than planned, making it meaningless to perform any statistical test. With regard to somatic and vasomotor symptoms, outcome was similar among the four groups, whereas improvement of psychological symptoms was higher in the isoflavones+melatonin group than in the other three. CONCLUSIONS: Present data do not show any advantage of isoflavones or melatonin over placebo for the relief of menopausal symptoms. However, the effect in psychological symptoms in the isoflavones + melatonin group should be further investigated.

Adult↗

PubMed2004

Picotamide, a combined inhibitor of thromboxane A2 synthase and receptor, reduces 2-year mortality in diabetics with peripheral arterial disease: the DAVID study.

AIMS: Patients with diabetes are at excessive risk of mortality and cardiovascular morbidity. Previous studies suggest that aspirin may be less effective in diabetic patients. In this multi-centre, randomized, double blind trial picotamide, a dual inhibitor of thromboxane A2 synthase and receptor, was compared with aspirin for the prevention of mortality and major cardiovascular events in diabetics with peripheral arterial disease (PAD). METHODS AND RESULTS: A total of 1209 adults aged 40-75 years with type 2 diabetes and PAD were randomized to receive picotamide (600 mg bid) or aspirin (320 mg od) for 24 months. The cumulative incidence of the 2 years overall mortality was significantly lower amongst patients who received picotamide (3.0%) than in those who received aspirin (5.5%) with a relative risk ratio for picotamide versus aspirin of 0.55 (95% CI: 0.31-0.98%). Events were reported in 43 patients (7.1%) on picotamide and 53 (8.7%) on aspirin. The combined endpoint of mortality and morbidity had a slightly lower incidence in the picotamide group but this difference did not reach statistical significance. CONCLUSION: Picotamide is significantly more effective than aspirin in reducing overall mortality in type 2 diabetic patients with associated PAD.

Adult↗

PubMed2004

[Studies of equivalence in cardiovascular diseases].

An increasing number of equivalence and non-inferiority trials appeared in recent years among randomized clinical trials, particularly for the evaluation of efficacy of treatments in cardiovascular medicine. These studies are characterized by remarkable methodological issues and important ethical implications. The aim of this review was to underscore some topic methodological problems: setting the equivalence boundary, the special logic used to establish equivalence, and the determinants of sample size. A Medline search was performed in order to identify the main problems in study design and in the interpretation of results of the equivalence and non-inferiority trials in cardiovascular diseases.

Cardiovascular Diseases↗

PubMed2004

[Equivalence studies in cardiovascular diseases].

Cardiovascular Diseases↗

PubMed2004

[Statistical notes. Absolute and relative effect measures].

The aim of these statistical notes was to give the cardiologist the suitable tools for the understanding of the statistical aspects in the reading of papers presenting the results of randomized controlled clinical trials, in the most simple and intuitive way, without any previous knowledge of basic statistics. The fundamentals of the most common tools for the comparison of two experimental treatments, are developed by getting cue from classical cardiological examples and by guiding the reader, step by step, toward the understanding and critical discussion of the proposed examples. In particular, this note focuses the attention on the main "indicators" of absolute and relative effect measures by evidencing their most important differences.

Cardiology↗

PubMed2004

[Statistical notes. From superiority to non-inferiority clinical trials: a leap in the dark?].

In these "statistical notes", equivalence and non-inferiority randomized controlled clinical trials (RCCT) are considered. Equivalence trials are designed to confirm the absence of a meaningful difference between the effect of two treatments. Non-inferiority trials are designed to prove that the new treatment is no less effective than an existing one: it may be more effective or it may have a similar effect. In this note the attention is addressed to suitable criteria for the choice of the tolerance margin epsilon, i.e. the largest difference which is clinically acceptable, so that a difference bigger than that would matter in practice. In particular, the procedures for the determination of the margin epsilon, used by the authors of the non-inferiority RCCT COBALT and INJECT, are presented and discussed in detail. The ethical implications of equivalence and non-inferiority RCCT are here considered and the reader is repeatedly invited to consider the appropriateness of the basic arguments asserted by the supporters of this kind of studies.

Algorithms↗

PubMed2003

Is axillary lymph node dissection necessary in elderly patients with breast carcinoma who have a clinically uninvolved axilla?

BACKGROUND: Axillary dissection in elderly patients with early-stage breast carcinoma who do not have palpable axillary lymph nodes is controversial because of the associated morbidity of the surgery, reduced life expectancy of the patients, and efficacy of hormone therapy in preventing recurrences and axillary events. METHODS: The authors performed a retrospective analysis of 671 consecutive patients with breast carcinoma who were age >or= 70 years and who underwent conservative breast surgery with axillary dissection (172 patients) or without axillary dissection (499 patients). Tamoxifen always was given. The effects of axillary dissection compared with no axillary dissection on breast carcinoma mortality and distant metastasis were analyzed using multiple proportional-hazards regression models. Because the assignment to axillary treatment was nonrandom, covariate adjustments were made for baseline variables that influenced the decision to perform axillary dissection and for prognostic factors. RESULTS: The crude cumulative incidence curves for breast carcinoma mortality and distant metastasis did not appear to differ significantly between the two groups (P = 0.530 and P = 0.840, respectively). The crude cumulative incidences of axillary lymph node occurrence at 5 years and 10 years were 4.4% and 5.9%, respectively (3.1% and 4.1%, respectively, for patients with pT1 tumors). CONCLUSIONS: Elderly patients with breast carcinoma who have no evidence of axillary lymph node involvement may be treated effectively with conservative surgery and tamoxifen. Immediate axillary dissection is not necessary but should be performed in the small percentage of patients who later develop overt axillary lymph node involvement.

Aged↗

PubMed2003

HER2 overexpression and doxorubicin in adjuvant chemotherapy for resectable breast cancer.

PURPOSE: Human epidermal growth factor receptor 2 (HER2) overexpression was found to predict a good response in breast carcinoma patients treated with doxorubicin (Adriamycin [ADM]). Evidence from our recent study indicates that node-positive patients respond to cyclophosphamide, methotrexate, and fluorouracil (CMF) regardless of HER2 status. We address the issue of whether therapy regimens including CMF and ADM versus CMF alone have the same therapeutic effect in patients with HER2+ and HER2- tumors in terms of relapse-free survival (RFS) and overall survival (OS). METHODS: Archival specimens of the primary tumors from 506 patients in a prospective clinical trial were stained with the anti-HER2 monoclonal antibody CB11. Originally, patients were randomly allocated to receive either 12 courses of intravenous CMF or eight courses of the same regimen followed by four cycles of ADM. RFS and OS were analyzed by a Cox model taking into account treatment, HER2 status, and the interaction between treatment and HER2 status, adjusting for the effect of other known clinical and biopathologic factors. RESULTS: Analysis of survival rates indicates a possible differential effect of treatment in the patients grouped according to HER2 status. Improved RFS and OS were observed in the HER2+ subgroup after treatment with CMF plus ADM versus CMF alone. With a median follow-up of 15 years, the hazard ratio (HR) for RFS was 0.83 in HER2+ tumors and 1.22 in HER2- tumors. The effect of treatment was more evident on OS in HER2+ patients (HR = 0.61; CI, 0.32 to 1.16) than in HER2- patients (HR = 1.26). CONCLUSION: Our data indicate that adding ADM to CMF might be beneficial for patients with HER2+ tumors.

Adult↗