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Biomedical subjects

M Loeffler

Publications and source records attributed to M Loeffler.

At least 19 recordsLinked to original sources
PubMed2006

Incidence and risk factors of central nervous system recurrence in aggressive lymphoma--a survey of 1693 patients treated in protocols of the German High-Grade Non-Hodgkin's Lymphoma Study Group (DSHNHL).

BACKGROUND: Central nervous system (CNS) relapse is a devastating and usually fatal complication of aggressive lymphoma. The extent of the disease, the proliferation rate and the sites of extranodal involvement have been discussed as risk factors. We analyzed the patients treated on protocols of the German High-Grade Non-Hodgkin's Lymphoma Study Group (DSHNHL) between 1990 and 2000, evaluated the rate and prognostic factors for CNS recurrence and developed a risk model trying to identify subsets of patients suitable for future prophylactic strategies. PATIENTS AND METHODS: From 1993 to 2000, 1399 patients [ 60 years irrespective of LDH] were randomized to receive six cycles of combination chemotherapy with cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP)-21, CHOP-14 or six cycles of CHOP+etoposide (CHOEP)-21, CHOEP-14 in a 2x2 factorial study design in the NHL-B1/B2 studies. From 1990 to 1997, 312 patients<or=60 years with an elevated LDH were randomized to five cycles CHOEP+involved field (IF) radiotherapy or three cycles CHOEP followed by high-dose BCNU, etoposide, cytarabine and melphalan (BEAM) and autologous stem-cell transplantation (NHL-A study). RESULTS: A total number of 1711 patients were initially eligible for this study, of whom 18 patients had to be excluded due to primary CNS involvement. In the remaining 1693 assessable patients, 37 cases of relapse or progression to the CNS (2.2%) were observed. The protocol asked for an intrathecal (i.th.) prophylaxis in patients with lymphoblastic lymphoma only (n=17), but overall 71 patients (71 of 1693=4.2%) received prophylaxis by decision of the treating physicians. Multivariate Cox regression analysis identified increased LDH (P<0.001) and involvement of more than one extranodal site (P=0.002) as independent predictors of CNS recurrence in the NHL-B1/B2 study population. Treatment with etoposide also evolved as a prognostic factor because the risk of CNS failure was significantly reduced after CHOEP (P=0.017). Elderly patients presenting with both an elevated LDH and lymphoma involvement in liver, bladder or adrenals had an up to 15-fold risk of spread of the disease to the CNS. CONCLUSION: The incidence of CNS relapse in 1693 patients treated for aggressive lymphomas on DSHNHL protocols from 1990 to 2000 was low (2.2%), although CNS prophylaxis was administered to <5% of patients. Thus, a general prophylaxis for all patients is not warranted, the less so since the effectiveness of i.th. prophylaxis itself is judged controversially. Increased LDH and involvement of more than one extranodal site were confirmed as independent risk factors. A cumulative 20% incidence of CNS disease in certain prognostic subgroups of elderly patients may render these candidates for i.th. prophylaxis; however, this approach would imply a potential overtreatment of approximately 80% of these patients deemed at high risk.

Adolescent↗
PubMed2006

The role of radical prostatectomy in patients with clinically localized prostate cancer and a prostate-specific antigen level >20 ng/ml.

OBJECTIVES: To determine the outcome of patients with a serum prostate-specific antigen (PSA) level >20 ng/ml that underwent radical prostatectomy (RP). METHODS: We retrospectively reviewed the medical records of 147 patients who underwent RP for clinically localized prostate cancer with a pre-treatment PSA (PSApt) >20 ng/ml. Fifty-two patients had positive pelvic lymph nodes and were excluded from analysis. Of 95 patients remaining, 15 were lost to follow-up. Therefore, the study group included 80 patients. The end points for this analysis were biochemical relapse-free survival (bRFS), surgical and post-operative complications and urinary continence. PSApt, pathological grade, surgical margin status, age, clinical stage and immediate androgen ablation were evaluated in a multivariate analysis regarding bRFS. RESULTS: Forty-nine resected specimens (61.2%) were pathologically classified as pT3 or pT4. After a mean follow-up of 64 months, the estimated 5-year bRFS rate was 58% for the overall group. Immediate androgen ablation was the only independent prognostic factor for biochemical relapse (P=0.001). Concerning the 21 patients who received an immediate androgen ablation after RP, the estimated 5-year bRFS rate was 92%. Complete urinary continence was achieved in 76.5% of patients. Early complications occurred in 13 patients (16.2%). CONCLUSIONS: Clinically localized prostate cancer with a PSApt >20 ng/ml is considered as having a poor prognosis. However, RP performed in these patients led to an acceptable morbidity and good functional results. Immediate adjuvant hormonal therapy seems mandatory in this setting to improve bRFS.

Carcinoma↗
PubMed2005

AdaptFlow: protocol-based medical treatment using adaptive workflows.

OBJECTIVES: In many medical domains investigator-initiated clinical trials are used to introduce new treatments and hence act as implementations of guideline-based therapies. Trial protocols contain detailed instructions to conduct the therapy and additionally specify reactions to exceptional situations (for instance an infection or a toxicity). To increase quality in health care and raise the number of patients treated according to trial protocols, a consultation system is needed that supports the handling of the complex trial therapy processes efficiently. Our objective was to design and evaluate a consultation system that should 1) observe the status of the therapies currently being applied, 2) offer automatic recognition of exceptional situations and appropriate decision support and 3) provide an automatic adaptation of affected therapy processes to handle exceptional situations. METHODS: We applied a hybrid approach that combines process support for the timely and efficient execution of the therapy processes as offered by workflow management systems with a knowledge and rule base and a mechanism for dynamic workflow adaptation to change running therapy processes if induced by changed patient condition. RESULTS AND CONCLUSIONS: This approach has been implemented in the AdaptFlow prototype. We performed several evaluation studies on the practicability of the approach and the usefulness of the system. These studies show that the AdaptFlow prototype offers adequate support for the execution of real-world investigator-initiated trial protocols and is able to handle a large number of exceptions.

Clinical Protocols↗
PubMed2004

Modelling human granulopoiesis under poly-chemotherapy with G-CSF support.

Cytotoxic drugs administered in polychemotherapy cause a characteristic neutropenic period depending on the schedule of the drugs, which can partly be prevented by G-CSF growth factor support. To quantify these effects and to gain a deeper insight into the dynamics of bone marrow recovery after such suppressing and stimulating disturbances, we construct a biomathematical compartment model of human granulopoiesis under polychemotherapy with G-CSF support. The underlying assumptions and mathematical techniques used to obtain the model are explained in detail. A large variety of biological and clinical data as well as knowledge from a model of murine haematopoiesis are evaluated to construct a physiological model for humans. Particular emphasis is placed on estimating the influence of chemotherapeutic drugs on the granulopoietic system. As a result, we present an innovative method to estimate the bone marrow damage caused by cytotoxic drugs with respect to single identifiable cell stages only on the basis of measured peripheral blood leukocyte dynamics. Conversely, our model can be used in a planning phase of a clinical trial to estimate the haematotoxicity of regimens based on new combinations of drugs already considered and with or without growth factor support.

Animals↗
PubMed2004

Comparison of external radiation therapy vs radical prostatectomy in lymph node positive prostate cancer patients.

INTRODUCTION: Treatment options for lymph node positive prostate cancer are limited. We retrospectively compared patients who underwent external radiotherapy (ERT) to patients treated by radical prostatectomy (RPX). MATERIALS AND METHODS: A total of 102 lymph node positive patients from the RPX series at Ulm University were evaluated. In all, 76 patients received adjuvant androgen withdrawal as part of their primary treatment. In the ERT group, 44 patients were treated at the University of Michigan using a fractionated regimen. Of these, 21 patients received early adjuvant hormonal therapy. Patients with neoadjuvant therapy before RPX or ERT were excluded. RESULTS: In the RPX group, PSA nadir (nadir < or = 0.2 vs > 0.2 ng/ml) showed a strong association with outcome. In the ERT group, pretreatment PSA was an independent predictor of outcome (P = 0.04) and patients with adjuvant hormonal therapy had a significant longer recurrence-free interval compared to patients without adjuvant therapy (P = 0.004). Comparing only patients with adjuvant hormonal treatment after cancer-specific therapy, the ERT-treated patients had a borderline longer PSA recurrence-free survival time compared to the RPX-treated patients (P = 0.05). CONCLUSIONS: In case of positive lymph nodes, RPX and ERT might be considered and need to be explained to the patient. For future treatment decisions, the presented findings and a potential survival benefit need to be evaluated in a larger prospective setting.

Aged↗
PubMed2004

Treatment of advanced Hodgkin's disease with COPP/ABV/IMEP versus COPP/ABVD and consolidating radiotherapy: final results of the German Hodgkin's Lymphoma Study Group HD6 trial.

BACKGROUND: The purpose of this study was to compare the efficacy of the hybrid chemotherapeutic regimen COPP/ABV/IMEP (cyclophosphamide-vincristine-procarbazine-prednisone-doxorubicin-bleomycin-vinblastine-ifosfamide-methotrexate-etoposide) (CAI) with that of the standard regimen COPP/ABVD (COPP/ABV, dacarbacine) (CA) in the treatment of advanced-stage Hodgkin's disease (HD). PATIENTS AND METHODS: Between January 1988 and January 1993, 588 eligible patients with HD in stages IIIB and IV were randomly assigned to a treatment or control group. The treatment group received four cycles of CAI over a complete cycle duration of 43 days. The control group received four cycles of CA over 57 days. Both groups then received consolidating radiotherapy. RESULTS: Five hundred and eighty-four patients were suitable for arm comparison. Patients in each group were similar in age, sex, histological subtype and clinical risk factors. Complete remission rates, overall survival and freedom from treatment failure at 7 years were similar for the two groups: 77% versus 78%, 73% versus 73% and 54% versus 56% for CAI and CA, respectively. Differences in acute chemotherapy-related toxicity were significant, however. Prognostic factor analysis confirmed the relevance of the International Prognostic Index and revealed that stage IVB, low hemoglobin, low lymphocyte count, high age and male gender were associated with a poor prognosis CONCLUSION: The rapidly alternating hybrid CAI did not give superior results when compared with the standard regimen CA in advanced-stage HD.

Adolescent↗
PubMed2004

Standardized terminology for clinical trial protocols based on top-level ontological categories.

This paper describes a new method for the ontologically based standardization of concepts with regard to the quality assurance of clinical trial protocols. We developed a data dictionary for medical and trial-specific terms in which concepts and relations are defined context-dependently. The data dictionary is provided to different medical research networks by means of the software tool Onto-Builder via the internet. The data dictionary is based on domain-specific ontologies and the top-level ontology of GOL. The concepts and relations described in the data dictionary are represented in natural language, semi-formally or formally according to their use.

Clinical Trials as Topic↗
PubMed2003

Low acute hematological toxicity during chemotherapy predicts reduced disease control in advanced Hodgkin's disease.

Chemotherapy-treated patients with advanced Hodgkin's disease (HD) differ considerably in acute hematotoxicity. Hematotoxicity may be indicative of pharmacological and metabolic heterogeneity. We hypothesized that low hematotoxicity might correlate with reduced systemic dose and thus reduced disease control. A total of 266 patients with advanced HD treated with cyclophosphamide, vincristine, procarbazine, prednisone, doxorubicin, bleomycin, vinblastine, and dacarbazine (COPP-ABVD) were analyzed (HD6 trial of the German Hodgkin's Lymphoma Study Group). The reported WHO grade of leukocytopenia was averaged over chemotherapy cycles given and weighted with the reciprocal dose intensity of the corresponding cycle. The low and high toxicity groups were defined in retrospect as having had an averaged WHO grade of leukocytopenia </=2.1 and >2.1, respectively. The independent impact of low hematological toxicity on freedom from treatment failure (FFTF) was assessed multivariately adjusting for the international prognostic score for advanced HD. The results were validated in two independent cohorts [181 patients treated with COPP-ABVD (HD9-trial) and 250 patients treated with COPP-ABV-ifosfamide, methotrexate, etoposide, and prednisone (IMEP) (HD6 trial)]. The 5-year FFTF rates were 68% for patients with high toxicity vs 47% for patients with low toxicity [multivariate relative risk (RR) 2.0, 95% confidence interval (CI) 1.4-3.0, p=0.0002]. Patients with low toxicity received significantly higher nominal dose ( p=0.02) and dose intensity ( p<0.0001). This finding was confirmed in both validation cohorts (multivariate RR 2.1, 95% CI 1.2-3.8, p=0.01 and RR 1.5, 95% CI 1.01-2.26, p=0.04, respectively). Patients with low hematotoxicity have significantly higher failure rates despite higher doses and dose intensity. Hematotoxicity is an independent prognostic factor for treatment outcome. This observation suggests a strategy of individualized dosing adapted to hematotoxicity.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2003

Practicability and acute haematological toxicity of 2- and 3-weekly CHOP and CHOEP chemotherapy for aggressive non-Hodgkin's lymphoma: results from the NHL-B trial of the German High-Grade Non-Hodgkin's Lymphoma Study Group (DSHNHL).

BACKGROUND: There is evidence that intensified variants of the classical 3-weekly CHOP-21 chemotherapy [cyclophosphamide (C), doxorubicin (H), vincristine (O), prednisone (P)] may improve treatment outcome in aggressive lymphoma. Three variants using either an addition of etoposide (CHOEP-21: 100 mg/m(2) on days 1-3), the shortening to 2-week intervals using recombinant human granulocyte colony-stimulating factor (rhG-CSF; CHOP-14) or both (CHOEP-14) are currently compared with CHOP-21 in the NHL-B trial of the German High-Grade Non-Hodgkin's Lymphoma Study Group (DSHNHL). To enable more extensive testing of these schemes we here characterise their practicability regarding schedule adherence, acute haematotoxicity and need for supportive treatment. PATIENTS AND METHODS: The trial included patients with normal lactate dehydrogenase (LDH) aged </=60 years (NHL-B1) and patients aged 61-75 years (NHL-B2). The data are taken from an interim analysis. Data from 959 patients (CHOP-21: 232; CHOP-14: 238; CHOEP-21: 244; CHOEP-14: 245) from 162 institutions with a total of 5331 therapy cycles were evaluated. RESULTS: The dose adherence in the NHL-B1 trial was excellent. The median relative dose (RD; i.e. actually given compared to planned dose) exceeds 98% for the myelosuppressive drugs in all four regimens. Only </=5% of patients received a relative dose <80% (RD <80). The median treatment duration could be shortened as scheduled for both CHOP-14 by 36 days and CHOEP-14 by 35 days. The dose adherence in the NHL-B2 trial was excellent for CHOP-21 and CHOP-14 for the myelosuppressive drugs (median RD >/=98%, RD <80 </=15%). Addition of etoposide, however, was accompanied by more dose erosion (median RD >/=97%, RD <80 </=17% for CHOEP-21 and </=27% for CHOEP-14). The median treatment duration could be shortened by 34 days with CHOP-14 compared with CHOP-21. Less treatment shortening was feasible for CHOEP-14 compared with CHOP-21 (median of 29 days). CHOP-14 and CHOP-21 were similar regarding toxicity profile, rate of infection, use of antibiotics, rate of transfusions and hospitalisation. CHOEP schemes were associated with a higher rate of infections, more transfusion requirements, more antibiotic use and longer hospitalisation than the CHOP schemes, particularly in patients aged >60 years. Haematopoietic recovery was age- and treatment-related. CONCLUSIONS: CHOP-14 with the addition of rhG-CSF is safe and practicable in a large multicentre setting in patients aged 18-75 years. Despite shorter treatment intervals it can be delivered at the same dose as the classical 3-weekly CHOP with a comparable toxicity profile. The addition of etoposide is feasible and safe for patients </=60 years old in both the CHOEP-21 and CHOEP-14 schemes. For patients >60 years of age the addition of etoposide is associated with marked dose erosion due to increased toxicity. In this age group CHOEP should be used with caution.

Acute Disease↗
PubMed2002

Pre-processed caspase-9 contained in mitochondria participates in apoptosis.

As shown here, mitochondria purified from different organs (liver, brain, kidney, spleen and heart) contain both pro-caspase-9 and the processed, mature form of caspase-9. Purified liver mitochondria release mature caspase-9 upon induction of permeability transition in vitro. This is accompanied by a discrete increase in the enzymatic cleavage of pro-caspase-9 substrates. We found that SHEP neuroblastoma cells constitutively contain pre-processed caspase-9 in their mitochondria, using a combination of subcellular fractionation and immunofluorescence with an antibody specific for the processed caspase. This is a cell type-specific phenomenon since HeLa cells mitochondria mainly contain pro-caspase-9 and comparatively little processed caspase-9. Upon introduction of apoptosis, mitochondrial pro-caspase-9 translocates to the cytosol and to the nucleus. This phenomenon is inhibited by transfection with Bcl-2. In synthesis, we report the unexpected finding that mitochondria can contain a pre-processed caspase isoform in non-apoptotic cells. Bcl-2-mediated regulation of mitochondrial membrane permeabilization may contribute to apoptosis control by preventing mitochondrial, pre-processed caspase-9 from interacting with its cytosolic activators.

Apoptosis↗
PubMed2002

Cell kinetic studies in the murine ventral tongue epithelium: thymidine metabolism studies and circadian rhythm determination.

The oral mucosa is a rapidly replacing body tissue that has received relatively little attention in terms of defining its cell kinetics and cellular organization. The tissue is sensitive to the effects of cytotoxic agents, the consequence of which can be stem cell death with the subsequent development of ulcers and the symptoms of oral mucositis. There is considerable interest in designing strategies to protect oral stem cells and, hence, reduce the mucositis side-effects in cancer therapy patients. Here we present details of a new histometric approach designed to investigate the changing patterns in cellularity in the ventral tongue mucosa. This initial paper in a series of four papers presents observations on the changing patterns in the labelling index following tritiated thymidine administration, which suggest a delayed uptake of tritiated thymidine from a long-term intracellular thymidine pool, a phenomenon that will complicate cell kinetic interpretations in a variety of experimental situations. We also provide data on the changing pattern of mitotic activity through a 24-h period (circadian rhythms). Using vincristine-induced stathmokinesis, the data indicate that 54% of the basal cells divide each day and that there is a high degree of synchrony in mitotic activity with a mitotic peak occurring around 13.00 h. The mitotic circadian peak occurs 9-12 h after the circadian peak in DNA synthesis. The data presented here and in the subsequent papers could be interpreted to indicate that basal cells of BDF1 mice have an average turnover time of about 26-44 h with some cells cycling once a day and others with a 2- or 3-day cell cycle time.

Animals↗
PubMed2002

Cell kinetic studies in the murine ventral tongue epithelium: mucositis induced by radiation and its protection by pretreatment with keratinocyte growth factor (KGF).

Radiation kills or reduces reproductive capacity of proliferating cells, including stem cells. In the oral mucosae this can result in a decline in the number of cells in the tissue which, if severe enough, will result in the formation of an ulcer when the cellularity essentially reaches zero. We have used histometric measurements of cellularity following exposure to radiation in mouse ventral tongue epithelium as a model for oral mucositis (ulcer development). Here we provide further measurements of cellularity changes in the basal layer and in the epithelium as a whole at various times following 15, 20 or 25 Gy doses. The protective effects of prior treatment with keratinocyte growth factor (KGF) are also investigated. 20 Gy of 300 kV X-rays has become our standard reference dose and the changes in cellularity seen following this dose are highly reproducible, with minimum values being observed 6 days following irradiation. A higher dose results in a greater reduction of cellularity, although the minimum value also occurs at 6 days. A lower dose (15 Gy) results in a much shallower curve, with a minimum value being observed about 1 day earlier. These changes in cellularity can be related to the less sensitive index of mucositis, namely epithelial thickness. There is also a sharp peak in proliferation about 1 day after the minimum in cellularity, i.e. on day 7. The peak following a lower dose of radiation occurs a little earlier and, following the higher dose, the peak tends to be broader. Previous work and data presented in the preceding paper in this series has shown that KGF, given over a period of 3 days, results in a dramatic increase in epithelial thickness in oral mucosa, including the ventral tongue. As a result of the increased cellularity induced by KGF given before radiation, a delay in the fall in cellularity results, which is the consequence of the increased number of cells in the epithelium at the beginning of the study.

Animals↗
PubMed2002

A continuum model to analyse spatial cell fluxes from positional labelling data applied to cell migration in oral mucosa.

A novel method is presented which allows the estimation of the velocity of migrating cells from positional 3HTdR labelling data in spatially organized epithelial tissues. In a continuum approach, wave-like profiles of labelling index (LI) data, which travel away from the basal layer, are followed and compared with experimental LI profiles. The method yields estimates of migration velocity, cell flow, and turnover time. Results for the ventral tongue mucosa in a group of 55 BDF1 mice that were labelled at the same time of the day and culled at different time points within a 24-h period have been analysed. The results show a strong circadian rhythm in the migration velocity and the related parameters.

Animals↗
PubMed2001

Low-dose radiation is sufficient for the noninvolved extended-field treatment in favorable early-stage Hodgkin's disease: long-term results of a randomized trial of radiotherapy alone.

PURPOSE: To show that radiotherapy (RT) dose to the noninvolved extended field (EF) can be reduced without loss of efficacy in patients with early-stage Hodgkin's disease (HD). PATIENTS AND METHODS: During 1988 to 1994, pathologically staged patients with stage I or II disease who were without risk factors (large mediastinal mass, extranodal lesions, massive splenic disease, elevated erythrocyte sedimentation rate, or three or more involved areas) were recruited from various centers. All patients received 40 Gy total fractionated dose to the involved field areas but were randomly assigned to receive either 40 Gy (arm A) or 30 Gy (arm B) total fractionated dose for the clinically noninvolved EF. No chemotherapy was given. RT films were prospectively reviewed for protocol violations and recurrences retrospectively related to the applied RT. RESULTS: Of 382 recruited patients, 376 were eligible for randomized comparison, 190 in arm A and 186 in arm B. Complete remission was attained in 98% of patients in each arm. With a median follow-up of 86 months, 7-year relapse-free survival (RFS) rates were 78% (arm A) and 83% (arm B) (P =.093). The upper 95% confidence limit for the possible inferiority of arm B in RFS was 4%. Corresponding overall survival rates were 91% (arm A) and 96% (arm B) (P =.16). The most common causes of death (n = 27) were cardiorespiratory disease/pulmonary embolisms (seven), second malignancy (six), and HD (five). Protocol violation was associated with significantly poorer RFS. Nonirradiated nodes were involved in 42 of 52 reviewed relapses, infield areas in 18, marginal areas in 17, and extranodal sites in 16. CONCLUSION: EF-RT alone attains good survival rates in favorable early-stage HD. The 30-Gy dose is adequate for clinically noninvolved areas. Protocol violation worsens the subsequent prognosis. Relapse patterns suggest that systemic therapy can reduce the 20% long-term relapse rate.

Adolescent↗
PubMed2001

Control of mitochondrial membrane permeabilization by adenine nucleotide translocator interacting with HIV-1 viral protein rR and Bcl-2.

Viral protein R (Vpr), an apoptogenic accessory protein encoded by HIV-1, induces mitochondrial membrane permeabilization (MMP) via a specific interaction with the permeability transition pore complex, which comprises the voltage-dependent anion channel (VDAC) in the outer membrane (OM) and the adenine nucleotide translocator (ANT) in the inner membrane. Here, we demonstrate that a synthetic Vpr-derived peptide (Vpr52-96) specifically binds to the intermembrane face of the ANT with an affinity in the nanomolar range. Taking advantage of this specific interaction, we determined the role of ANT in the control of MMP. In planar lipid bilayers, Vpr52-96 and purified ANT cooperatively form large conductance channels. This cooperative channel formation relies on a direct protein-protein interaction since it is abolished by the addition of a peptide corresponding to the Vpr binding site of ANT. When added to isolated mitochondria, Vpr52-96 uncouples the respiratory chain and induces a rapid inner MMP to protons and NADH. This inner MMP precedes outer MMP to cytochrome c. Vpr52-96-induced matrix swelling and inner MMP both are prevented by preincubation of purified mitochondria with recombinant Bcl-2 protein. In contrast to König's polyanion (PA10), a specific inhibitor of the VDAC, Bcl-2 fails to prevent Vpr52-96 from crossing the mitochondrial OM. Rather, Bcl-2 reduces the ANT-Vpr interaction, as determined by affinity purification and plasmon resonance studies. Concomitantly, Bcl-2 suppresses channel formation by the ANT-Vpr complex in synthetic membranes. In conclusion, both Vpr and Bcl-2 modulate MMP through a direct interaction with ANT.

Amino Acid Sequence↗
PubMed2001

Five theses concerning the clinical consequences of pathology and prognostic factors.

We discuss possible justifications to split study populations from a biometrical point of view. The existence of prognostic differences between subgroups are neither a sufficient nor a necessary reason to justify a splitting decision. There are essentially two separate types of relevant arguments to justify a split of patient study populations: a) Different toxicity/benefit trade-offs concerning the acceptability of a particularly aggressive treatment, b) Evidence for strong treatment by subgroup interactions, i.e. Treatment differences differ markedly by biologically defined subgroups. The latter is what the research ideal of biologically specific treatment asks for. Subgroup analysis is notoriously difficult. Formal statistical analysis must be complemented by specific evidence from basic sciences. Meta-subgroup analyses may be an option if a biologically specific hypothesis on which treatment component interacts with what biological feature allows to operationally identify all those randomised trials in which the effect should be present. In this conceptual and methodological paper we defend five theses concerning the clinical consequences of pathological and biological differences from a somewhat unorthodox biometrical point of view.

Biometry↗
PubMed2001

Consolidation radiotherapy to bulky disease in aggressive NHL. First results of the NHL B-94 trial of the DSHNHL.

The impact of radiotherapy in aggressive NHL is not well defined. In the NHL B-94 trial of the DSHNHL, an irradiation of bulky disease areas was done after completing 6 cycles of CHOP/CHOEP chemotherapy. In the entire patient group, including those patients with extranodal disease and those who did not receive the complete chemotherapy, bulky disease was a significant independent prognostic factor concerning recurrence-free survival (66.1% (no bulk) vs. 53.3% (bulk), p=0.0001). Out of 366 patients with nodal disease only and 6 cycles of chemotherapy according to the protocol, 84 of 91 patients with bulky disease were irradiated with 36 Gy. In this group of patients the prognostic impact of bulky disease could not be shown any longer (recurrence-free survival 77.3% (no bulk) vs. 74.1% (bulk). Localized radiotherapy of bulky disease areas may therefore have contributed to an improvement in outcome in this high-risk group.

Antineoplastic Combined Chemotherapy Protocols↗