Biomedical subjects

P Broët

Publications and source records attributed to P Broët.

At least 19 recordsLinked to original sources

PubMed2004

Correlations between molecular profile and radiologic pattern in oligodendroglial tumors.

OBJECTIVE: To investigate possible correlations between tumor location and genetic alterations in a series of oligodendrogliomas. METHODS: A series of 158 consecutive oligodendrogliomas were retrospectively reviewed. In each case, the radiologic picture and the chromosome 1p (chr 1p) status of the tumor detected by the loss of heterozygosity technique were analyzed. Correlation between tumor location and molecular profile was made by chi2 tests. RESULTS: Eighty-eight of the 158 patients had low-grade oligodendrogliomas, and 70 had anaplastic oligodendrogliomas. Overall, oligodendrogliomas with chr 1p loss were located preferentially in the anterior part of the brain, whereas tumors with intact chr 1p affected mainly the posterior part of the brain (p = 0.0038). In terms of lobar involvement, a preferential location of oligodendrogliomas with chr 1p loss was found in the frontal lobes as compared with the temporal, parietal, and occipital tumors (p < 0.01). CONCLUSION: There is a significant correlation between loss of heterozygosity on chromosome 1p and tumor location in oligodendrogliomas, suggesting that subtypes of oligodendrogliomas could derive from site-specific precursors.

Adult↗

PubMed2004

Lack of relationship between EGFR-1 immunohistochemical expression and prognosis in a multicentre clinical trial of 93 patients with advanced primary ovarian epithelial cancer (GINECO group).

Epidermal growth factor receptor 1 (EGFR-1) overexpression is usually described as linked with a worse prognosis in a variety of tumours of epithelial origin. However, its role in ovarian cancer is still controversial. The aim of the present study was to analyse the prognostic impact of EGFR-1 in a retrospective series of 93 stage III-IV primary ovarian epithelial tumours. All patients, enrolled in a multicentre GINECO prospective clinical trial, were treated with the same platinum-based combination chemotherapy, and were followed up with a median of 69 months. Epidermal growth factor receptor 1 plasma membrane expression, assessed by immunohistochemistry on paraffin-embedded tissues, was correlated with clinical parameters as well as immunohistochemical expression results of HER-2 (c-erbB-2), BAX, BCL-2, p53 and anti-Ki-67, previously studied in the same series of patients. Positive immunostaining for EGFR-1 was seen in 31 of the 93 analysed cases (33%). No correlation was found between EGFR-1 expression and clinical parameters. No correlation was found between EGFR-1 expression and other biological markers, except for HER-2, which was limit for significance. Indeed, among the EGFR-1-negative cases, 10.3% expressed HER-2, whereas the HER-2-expressing tumours accounted for 27.6% of EGFR-1-positive cases (P=0.06). Epidermal growth factor receptor 1 overexpression had no prognostic impact on both overall and progression-free survival through univariate and multivariate analyses. The potential effect of EGFR-1 and HER-2 co-expression on targeted therapy against EGFR-1 and/or HER-2 molecules has to be further analysed.

Adult↗

PubMed2004

Temozolomide as initial treatment for adults with low-grade oligodendrogliomas or oligoastrocytomas and correlation with chromosome 1p deletions.

PURPOSE: To determine the response rate of low-grade oligodendroglial tumors (LGOT) to temozolomide (TMZ) as initial treatment and to evaluate the predictive value of chromosome 1p deletion on the radiologic response. PATIENTS AND METHODS: Adult patients with pathologically proven LGOT with progressive disease on magnetic resonance imaging (MRI) were eligible for the study. TMZ was administered at the starting dose of 200 mg/m2/d for 5 days, repeated every 28 days. Response was evaluated clinically and by central review of MRIs. Chromosome 1p and 19q deletions were detected by the loss of heterozygosity technique. RESULTS: Sixty consecutive patients were included in the study. At the time of analysis, the median number of TMZ cycles delivered was 11. Clinically, 51% of patients improved, particularly those with uncontrolled epilepsy. The objective radiologic response rate was 31% (17% partial response and 14% minor response), whereas 61% of patients had stable disease and 8% experienced disease progression. The median time to maximum tumor response was 12 months (range, 5 to 20 months). Myelosuppression was the most frequent side effect, with grade 3 to 4 toxicity in 8% of patients. Loss of chromosome 1p was associated with objective tumor response (P < .004). CONCLUSION: TMZ is well tolerated and provides a substantial rate of response in LGOT. Chromosome 1p loss is correlated with radiographic response and could be a helpful marker for guiding therapeutic decision making in LGOT.

Adult↗

PubMed2004

[Multiple comparison procedures: principles, limits. Applications to microarray phenotype-genotype analysis].

BACKGROUND: When analysing data which simultaneously implicate a large number of statistical tests, one of the main problems is to take into account the multiplicity of these tests. The huge amount of comparisons done in studies of which the aim is to detect, using microarray, genes whose transcriptional changes are related to a biological or clinical outcome leads to a renewed interest for the multiple comparisons problem. However, this problem concerns many other fields such as psychometry, epidemiology, genetics. RESULTS: First, we introduce the multiple comparison framework. Then, we present the main procedures based on a global error rate called the "Family Wise Error Rate" (FWER) and those based on a false discovery rate expectancy (the "False Discovery Rate" (FDR) and the "positive False Discovery Rate" (pFDR)). Next, we apply the different procedures on a real dataset from a breast carcinoma study. Finally, we discuss the main results and we present guidelines for the use of these procedures.

False Positive Reactions↗

PubMed2003

A score test for establishing non-inferiority with respect to short-term survival in two-sample comparisons with identical proportions of long-term survivors.

In recent years randomized trials designed to establish non-inferiority of a new treatment as compared to a standard one have been more widely used. Two-sample statistics have been proposed for this equivalence testing problem. However, they are not suited to situations where a long-term survivor fraction is expected. In this paper we propose a score test designed for establishing non-inferiority for the new treatment as compared to the standard one while assuming identical long-term survivor rates. Simulations results show that the proposed statistic has satisfactory size and power as long as certain restricting conditions are verified. A breast cancer trial is analysed as an example.

Breast Neoplasms↗

PubMed2001

Molecular heterogeneity of oligodendrogliomas suggests alternative pathways in tumor progression.

OBJECTIVE: To identify different genetic molecular profiles in oligodendrogliomas and to evaluate their prognostic significance. METHODS: The main genetic alterations reported in glial tumors were investigated in 26 oligodendrogliomas (10 World Health Organization grade II and 16 World Health Organization grade III). Correlation between identified molecular changes and pathologic grade or clinical course was subsequently analyzed using univariate and multivariate statistical analyses. RESULTS: Loss of heterozygosity (LOH) on chromosome 1p, 19q, and 10; P16/CDKN2A homozygous deletion; EGFR (epidermal growth factor receptor) amplification; and TP53 and PTEN mutations were observed in 14 (54%), 15 (58%), 9 (35%), 7 (27%), 5 (19%), 1 (4%), and 0 cases. LOH 1p and 19q were tightly associated (p < 0.0001). A mutual exclusion was found between LOH 1p/19q and EGFR amplification (p = 0.01), P16/CDKN2A deletions (p = 0.001), or LOH on 10q (p = 0.03), suggesting the existence of distinct genetic subsets in oligodendrogliomas. On univariate analysis, age <50 years (p = 0.002) and LOH 1p (p = 0.01) were associated with a longer progression-free survival (PFS) whereas LOH 10q (p = 0.03) and EGFR amplification (p = 0.007) were associated with a worse PFS. In multivariate analyses, age <50 years (p = 0.001) and LOH 1p (p = 0.006) remained independent predictive factors for PFS. CONCLUSION: These results provide evidence for two alternative molecular pathways of progression in oligodendrogliomas. The first one is associated with loss of 1p and 19q and the second one with P16/CDKN2A deletion, 10q loss, and EGFR amplification. The findings confirm the value of loss of 1p as predictor of longer progression-free survival; in addition, the study demonstrates the unfavorable impact of 10q loss and EGFR amplification on the prognosis.

Adult↗

PubMed2001

Thymidine kinase as a proliferative marker: clinical relevance in 1,692 primary breast cancer patients.

PURPOSE: To assess the prognostic value of thymidine kinase (TK), an enzyme involved in the DNA synthesis salvage pathway, relative to other prognostic factors in primary breast cancer. PATIENTS AND METHODS: This retrospective study involved 1,692 patients with operable breast cancer treated in six institutions (median follow-up, 82 months). Among the 857 node-negative patients, 135 received adjuvant chemotherapy (fluorouracil, doxorubicin, cyclophosphamide [FAC] or fluorouracil, etoposide, and cisplatin [FEC]). TK was assayed in cytosol with a quantitative radioenzymatic technique. Disease-specific survival (DSS), local recurrence-free interval (LRI), and distant-relapse-free interval (DRI) were investigated. RESULTS: High TK levels were associated with large tumor size, high histologic grade, and steroid hormone receptor negativity. Univariate analysis of the entire data set showed that high TK levels were related to shorter DSS (P < 10(-5)), LRI (P < 10(-3)), and DRI (P < 10(-5)). In time-dependent Cox models, high TK levels remained an independent predictor of the three outcomes, both in the overall population and in node-negative patients, although its prognostic value decreased over time. In node-negative patients, the introduction of an interaction term in multivariate analysis suggested that chemotherapy was more efficacious for patients who had tumors with high TK contents. In node-positive patients, high TK levels were related only to an increased risk of LRI. CONCLUSION: High TK values are an important risk factor in node-negative patients and seem to be associated with a beneficial effect of adjuvant FAC or FEC in patients who received adjuvant chemotherapy. The rationale of chemotherapy for patients with slowly proliferating tumors has to be discussed from a risk-benefit point of view.

Adult↗

PubMed2001

Cytotoxic synergism of methioninase in combination with 5-fluorouracil and folinic acid.

Potentiation of the cytotoxic activity of 5-fluorouracil (FUra) by folinic acid (5-HCO-H4folate) is due to elevation of the methylene tetrahydrofolate (CH2-H4folate) level, which increases the stability of the ternary complex of thymidylate synthase (TS), fluorodeoxyuridine monophosphate, and CH2-H4folate that inactivates the TS. Methionine deprivation results in the production of tetrahydrofolate (H4folate) and, subsequently, CH2-H4folate from methyl tetrahydrofolate, as a consequence of the induction of methionine synthesis. We hypothesized that the efficacy of FUra could be augmented by the combination of high-concentration 5-HCO-H4folate and recombinant methioninase (rMETase), a methionine-cleaving enzyme. Studies in vitro were performed with the cell line CCRF-CEM. Cytotoxic synergism of FUra + rMETase and FUra + 5-HCO-H4folate + rMETase was demonstrated with the combination index throughout a broad concentration range of FUra and rMETase. A subcytotoxic concentration of rMETase reduced the IC50 of FUra by a factor of 3.6, and by a factor of 7.5, in the absence and in the presence of 5-HCO-H4folate, respectively. 5-HCO-H4folate increased the intracellular concentrations of CH2-H4folate and H4folate from their baseline levels. Concentrations of folates were not changed by exposure to rMETase. Levels of free TS in cells treated with FUra + 5-HCO-H4folate and with FUra + rMETase were lower than those in cells exposed to FUra alone. The decrease of TS was still more pronounced in cells treated with FUra + 5-HCO-H4folate + rMETase. The synergism described in this study will be a basis for further exploration of combinations of fluoropyrimidines, folates, and rMETase.

Antimetabolites, Antineoplastic↗

PubMed2001

A semiparametric approach for the two-sample comparison of survival times with long-term survivors.

In the two-sample comparison of survival times with long-term survivors, the overall difference between the two distributions reflects differences occurring in early follow-up for susceptible subjects and in long-term follow-up for nonsusceptible subjects. In this setting, we propose statistics for testing (i) no overall, (ii) no short-term, and (iii) no long-term difference between the two distributions to be compared. The statistics are derived as follows. A semiparametric model is defined that characterizes a short-term effect and a long-term effect. By approximating this model about no difference in early survival, a time-dependent proportional hazards model is obtained. The statistics are obtained from this working model. The asymptotic distributions of the statistics for testing no overall or no short-term effects are ascertained, while that of the statistic for testing no long-term effect is valid only when the short-term effect is small. Simulation studies investigate the power properties of the proposed tests for different configurations. The results show the interesting behavior of the proposed tests for situations where a short-term effect is expected. An example investigating the impact of progesterone receptors status on local tumor relapse for patients with early breast cancer illustrates the use of the proposed tests.

Biometry↗

PubMed2000

Second line chemotherapy with docetaxel in patients with recurrent malignant glioma: a phase II study.

The objective of the study was to assess the efficacy of docetaxel in recurrent supratentorial malignant gliomas. The sample size of the study was determined by the Gehan's method for a response rate of 20% and a beta error of 5%. In the first step 14 patients (age 27-69, median 50; Karnofsky index 50-90, median 75) with recurrent malignant glioma after surgery, radiotherapy and nitrosourea, were enrolled (12 glioblastomas, 2 anaplastic astrocytomas). Docetaxel at the initial dose of 80 mg/m2 was administered every 3 weeks until progression or unacceptable toxicity. A total of 41 cycles was administered. Patients received a median of two cycles (range 1-6). No complete or partial response was observed. Therefore, according to the design of the study, no additional patients were enrolled and the trial was terminated. Two stabilizations were observed (14 and 15 weeks). Median TTP was 7 weeks (44 days). Median overall survival from recurrence was 26.5 weeks (6.4 months). Grade 3-4 neutropenia was observed in 8 patients (57%) but no life-threatening toxicity was observed. Other toxicities were uncommon and mild. Dose reduction was performed in 5 patients. This study suggests that docetaxel displayed no significant activity in patients with malignant recurrent gliomas.

Adult↗

PubMed1999

Clinical outcome of patients with anti-Hu-associated encephalomyelitis after treatment of the tumor.

OBJECTIVE: To evaluate 1) the effect of the tumor treatment on the clinical course of paraneoplastic encephalomyelitis (PEM) with anti-Hu antibodies, 2) the impact of immunotherapy on the tumor evolution, and 3) the outcome of the small cell lung cancer (SCLC) of PEM patients compared with that of patients without PEM. METHODS: The authors retrospectively analyzed 51 PEM patients (42 with SCLC, 9 with other tumors) who received antineoplastic treatment with (25 patients) or without (26) concomitant immunotherapy. Tumor response was assessed at the end of the antineoplastic treatment. Progression of PEM was defined as a change of at least 1 point in the Rankin scale measured at the onset and at the end of the tumor treatment. To evaluate the outcome of SCLC, 27 PEM patients with SCLC were matched one-to-one with SCLC patients without PEM for age, performance status, tumor stage, and type of antineoplastic treatment. RESULTS: Thirty-six (70%) patients were neurologically stable at the end of the tumor treatment. In a logistic regression analysis, tumor complete response was the only predictor of PEM stabilization (OR 7.07; 95% CI 1.68 to 29.76; p = 0.006). Immunotherapy did not modify the outcome of the tumor and PEM. Median survival was similar in SCLC patients with and without PEM, but the probability of survival at 30 months was higher in PEM patients with SCLC (OR 5.26; 95% CI 1.0004 to 27.6902; p = 0.03). CONCLUSIONS: Complete response of the tumor seems to have a favorable influence on the course of paraneoplastic encephalomyelitis (PEM). Concomitant immunotherapy does not adversely affect the tumor outcome. The small cell lung cancer of PEM patients may have a slightly better evolution than that of patients without PEM.

Adult↗

PubMed1999

Unobserved covariates in the two-sample comparison of survival times: a maximum efficiency robust test.

In analysing a clinical trial with the logrank test, the hazards between the two groups are usually assumed to be proportional. Nevertheless, this hypothesis is no longer valid with unobserved covariates. As a consequence, there is a loss of power of the logrank test for testing the null hypothesis H(0) of no treatment effect. We propose a test suited for taking into account unobserved covariates. The proposed approach is based on a proportional hazard frailty model whereby the omitted covariates are considered as an unobserved frailty variable. The procedure is as follows. In a first step, the weighted logrank test optimal for testing H(0) against a general proportional hazard frailty model is obtained and its specialization for a gamma frailty variable is derived. In a second step, the proposed test is obtained by combining the maximin efficiency robustness principle and the gamma frailty distribution properties. Simulation studies investigate the power properties of the test for different frailty distributions. A breast cancer clinical trial is analysed as an example. The proposed test might be recommended rather than the logrank for practical situations in which one expects heterogeneity related to omitted covariates.

Breast Neoplasms↗

PubMed1999

Analyzing prognostic factors in breast cancer using a multistate model.

In breast cancer clinical research, an important goal is to analyze how factors are seen to affect the disease process. Meanwhile, the disease progression is not fully modelled using standard analysis since transitions between intermediate events such as local-regional recurrences (LRR) or metachronous contralateral breast cancer (MCBC) are not considered. In the present study, the progression of disease was modelled using a multistate model. By this approach, we assessed transitions during the course of the disease and studied prognostic factors for each transition. The model was applied to 6,185 patients with unilateral ductal invasive breast cancer, clinical stage I through III, treated between 1981 and 1988 at the Curie Institute. At first diagnosis, high clinical stage, high histological grade, positive lymph nodes, and age less than 40 years were associated with increased risks of LRR, metastases, or death. Except age, the same factors remained predictive for metastases or death following LRR. Chemotherapy for the first cancer was associated with a decreased risk for developing MCBC. As the time interval from diagnosis of the primary tumor to that of a local or contralateral recurrence increased, the risk of metastases or death decreased. Nodal status for the first tumor and clinical stage for the contralateral tumor increased the risk of metastases or death following MCBC. Conversely, the risk decreased for patients who received adjuvant hormone therapy following MCBC. In conclusion, the multistate model offers us a much more appropriate way to study prognostic factors for each transition in breast cancer disease.

Adult↗

PubMed1999

Short and long-term effects on survival in breast cancer patients treated by primary chemotherapy: an updated analysis of a randomized trial.

A potential advantage of primary over adjuvant chemotherapy in breast cancer survival had been proposed on theoretical grounds. In 1994, early results of the S6-trial comparing primary chemotherapy vs. adjuvant chemotherapy for operable breast cancer in 390 premenopausal patients had shown significant improvement in survival of the primary chemotherapy arm (p = 0.04). An updated analysis conducted in 1995 showed the disappearance of this difference between the two arms (p = 0.18). In the present analysis, we investigated the potential short and long-term benefits attributable to primary chemotherapy by applying weighted logrank tests designed to assess specifically these effects. Results were compared to those obtained with the classical logrank test. At a median follow-up of 105 months, a significant short-term survival benefit (p = 0.02) in favor of the primary chemotherapy has been shown. However, no long-term survival benefit (p = 0.36) could be documented. The classical logrank test had revealed no significant difference (p = 0.24) between the two groups but the proportional hazard assumption being rejected (p = 0.04), the efficiency of this test can be questioned. Results using the present analysis suggested that primary chemotherapy delayed early death rates, without significantly modifying long-term event rates. It emphasizes that a short-term effect which is not necessarily associated with a long-term benefit may be seen at an early evaluation and disappear later on.

Antineoplastic Agents↗

PubMed1999

Treatment of supratentorial glioblastoma multiforme with radiotherapy and a combination of BCNU and tamoxifen: a phase II study.

From May 1990 to November 1994, 70 consecutive patients suffering from glioblastoma multiforme were treated following surgery with conventional radiotherapy and adjuvant IV BCNU administered alone or in combination with tamoxifen. Twenty-five patients received BCNU alone (control group A) while 24 patients also received 40 mg of tamoxifen (TMX) PO daily (group B) and 21 received 100 mg of TMX PO daily (group C). There were no significant differences between the 3 groups concerning age, type of resection and median post-operative Karnofsky performance status (KPS). Blood toxicity over grade II occurred in 33.5% of patients receiving TMX versus 12% of patients treated with BCNU alone (p < 0.05). Deep venous thrombosis complications were observed in 4 patients of each TMX group, whereas they were not observed in the control group (p < 0.04). Median time to tumor progression (MTTP) was 35 weeks in the control group and 27 weeks in both TMX groups B and C. Median survival time (MST) was 56, 66 and 51 weeks, respectively. These results suggest that the addition of TMX to standard treatment of glioblastomas does not affect the time to tumor progression and overall survival but may increase the risk of deep venous thrombosis or nitrosourea-induced blood toxicity.

Adult↗

PubMed1999

Prognostic value of uPA and p53 accumulation measured by quantitative biochemical assays in 1245 primary breast cancer patients: a multicentre study.

The purpose of this retrospective multicentre study was to assess the prognostic value of urokinase plasminogen activator (uPA) and p53 levels in a large series of primary breast cancer, using an automatic quantitative luminometric method. Samples of 1245 operable breast tumours were collected from seven French institutions and patients were followed for a median of 75 months. The median uPA and p53 levels assayed in cytosols by means of the immunoluminometric technique (LIA) were 0.31 and 0.20 ng mg(-1) of protein respectively. In univariate analysis, high levels of uPA and p53 were associated with shorter disease-specific survival, disease-free interval, and distant recurrence-free interval. The 5-year survival rates were 95.5% among patients with uPA values below the 20th percentile, and 77.5% in those with values above the 80th percentile. The 5-year survival rates were 91.0% in patients with p53 values below the 20th percentile, and 77.6% in those with values above the 80th percentile. In multivariate analysis, the risk of disease-related death increased with uPA levels after adjustment for tumour size, histological grade, lymph node involvement, and estrogen receptor status. A high level of uPA was also related to a shorter disease-free interval and distant recurrence-free interval. In node-negative patients, a high level of uPA remained strongly related to the three outcomes. When adjusted for other prognostic factors, p53 was no longer significantly related to the outcomes. Given its rapidity and simple application to routinely prepared cytosols, this LIA may be useful for evaluating the prognostic impact of uPA in primary breast cancer, particularly in node-negative patients. According to our results, the prognostic value of p53 accumulation is limited when uPA is included in multivariate analysis.

Adult↗

PubMed1998

Primary central nervous system lymphomas in 72 immunocompetent patients: pathologic findings and clinical correlations. Groupe Ouest Est d'étude des Leucénies et Autres Maladies du Sang (GOELAMS)

We reviewed 72 primary central nervous system lymphomas occurring in immunocompetent patients. The cases were reviewed for clinical data, histology, immunophenotype, bcl-2 and p53 expression, and Epstein-Barr virus association. Follow-up was available for 40 patients included in the Groupe Ouest Est d'étude des Leucénies et Autres Maladies du Sang (GOELAMS) lymphomes cérébraux primitifs (LCP 88) trial. Each diagnosis, requiring a consensus among at least 3 pathologists, was performed according to the recent Revised European-American Lymphoma classification and equivalents in the updated Kiel classification. Tumors were predominantly classified as diffuse large B-cell lymphomas. There were 3 T-cell lymphomas and 1 Hodgkin lymphoma. The proteins bcl-2 and p53 were expressed in 35% and 16% of the tested cases, respectively. Epstein-Barr virus was not found by in situ hybridization except in the case classfied as a cerebral localization of Hodgkin disease. No significant association was found between subtypes, bcl-2 or p53 expression, and patient survival. From the standpoint of their biologic characteristics, primary central nervous system lymphomas are very similar to systemic diffuse large B-cell lymphomas. In contrast to AIDS-related primary central nervous system lymphomas, primary central nervous system lymphomas are rarely associated with Epstein-Barr virus and in immunocompetent patients they express bcl-2 at a relatively low rate.

Adult↗

PubMed1998

[Long-term prognostic role of steroid receptors in cancer of the breast].

We screened for the prognostic value of estrogen receptor (ER) and progesterone receptor (PR) through a multicentric study of 2,257 operable breast cancer patients who did not received adjuvant therapy. Three hundred and seven local-regional recurrences, 105 metachronous contralateral breast cancer, 589 metastases and 537 deaths from cancer had been diagnosed with a median follow-up of 8.5 years. A total of 69% of the tumors were ER positive and 54% PR positive. For statistical analysis, 1,665 patients were studied because of complete clinical and biological data. In univariate analysis, ER and PR status were of prognostic value for the metastases-free interval (MFI) and the overall survival (OS). In multivariate analysis (Cox proportional hazard model), only the ER status showed a significant difference between positive and negative groups regarding the MFI and OS. By using Cox regression model with time-dependent covariates, we show that the predictive value of ER status of the primary tumor decreases by approximately 20% per year, losing its significance after 8 years of follow-up. These results show that ER and PR status have a relatively limited predictive value and their major interest remain in the domain of therapeutic decision.

Adult↗