Dataset Information

Obesity and risk of recurrence or death after adjuvant endocrine therapy with letrozole or tamoxifen in the breast international group 1-98 trial.

ABSTRACT:

Purpose

To examine the association of baseline body mass index (BMI) with the risk of recurrence or death in postmenopausal women with early-stage breast cancer receiving adjuvant tamoxifen or letrozole in the Breast International Group (BIG) 1-98 trial at 8.7 years of median follow-up.

Patients and methods

This report analyzes 4,760 patients with breast cancer randomly assigned to 5 years of monotherapy with letrozole or tamoxifen in the BIG 1-98 trial with available information on BMI at randomization. Multivariable Cox modeling assessed the association of BMI with disease-free survival, overall survival (OS), breast cancer-free interval, and distant recurrence-free interval and tested for treatment-by-BMI interaction. Median follow-up was 8.7 years.

Results

Seventeen percent of patients have died. Obese patients (BMI ≥ 30 kg/m(2)) had slightly poorer OS (hazard ratio [HR] = 1.19; 95% CI, 0.99 to 1.44) than patients with normal BMI (< 25 kg/m(2)), whereas no trend in OS was observed in overweight (BMI 25 to < 30 kg/m(2)) versus normal-weight patients (HR = 1.02; 95% CI, 0.86 to 1.20). Treatment-by-BMI interactions were not statistically significant. The HRs for OS comparing obese versus normal BMI were HR = 1.22 (95% CI, 0.93 to 1.60) and HR = 1.18 (95% CI, 0.91 to 1.52) in the letrozole and tamoxifen groups, respectively.

Conclusion

There was no evidence that the benefit of letrozole over tamoxifen differed according to patients' BMI.

SUBMITTER: Ewertz M

PROVIDER: S-EPMC3488270 | biostudies-literature | 2012 Nov

REPOSITORIES: biostudies-literature

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Publications

Obesity and risk of recurrence or death after adjuvant endocrine therapy with letrozole or tamoxifen in the breast international group 1-98 trial.

Ewertz Marianne M Gray Kathryn P KP Regan Meredith M MM Ejlertsen Bent B Price Karen N KN Thürlimann Beat B Bonnefoi Hervé H Forbes John F JF Paridaens Robert J RJ Rabaglio Manuela M Gelber Richard D RD Colleoni Marco M Láng István I Smith Ian E IE Coates Alan S AS Goldhirsch Aron A Mouridsen Henning T HT

Journal of clinical oncology : official journal of the American Society of Clinical Oncology 20121008 32

<h4>Purpose</h4>To examine the association of baseline body mass index (BMI) with the risk of recurrence or death in postmenopausal women with early-stage breast cancer receiving adjuvant tamoxifen or letrozole in the Breast International Group (BIG) 1-98 trial at 8.7 years of median follow-up.<h4>Patients and methods</h4>This report analyzes 4,760 patients with breast cancer randomly assigned to 5 years of monotherapy with letrozole or tamoxifen in the BIG 1-98 trial with available information ...[more]

PMID: 23045588

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Project description:BackgroundAdjuvant tamoxifen therapy is effective for postmenopausal women with endocrine-responsive breast cancer. Cytochrome P450 2D6 (CYP2D6) enzyme metabolizes tamoxifen to clinically active metabolites, and CYP2D6 polymorphisms may adversely affect tamoxifen efficacy. In this study, we investigated the clinical relevance of CYP2D6 polymorphisms.MethodsWe obtained tumor tissues and isolated DNA from 4861 of 8010 postmenopausal women with hormone receptor-positive breast cancer who enrolled in the randomized, phase III double-blind Breast International Group (BIG) 1-98 trial between March 1998 and May 2003 and received tamoxifen and/or letrozole treatment. Extracted DNA was used for genotyping nine CYP2D6 single-nucleotide polymorphisms using polymerase chain reaction-based methods. Genotype combinations were used to categorize CYP2D6 metabolism phenotypes as poor, intermediate, and extensive metabolizers (PM, IM, and EM, respectively; n = 4393 patients). Associations of CYP2D6 metabolism phenotypes with breast cancer-free interval (referred to as recurrence) and treatment-induced hot flushes according to randomized endocrine treatment and previous chemotherapy were assessed. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). All statistical tests were two-sided.ResultsNo association between CYP2D6 metabolism phenotypes and breast cancer-free interval was observed among patients who received tamoxifen monotherapy without previous chemotherapy (P = .35). PM or IM phenotype had a non-statistically significantly reduced risk of breast cancer recurrence compared with EM phenotype (PM or IM vs EM, HR of recurrence = 0.86, 95% CI = 0.60 to 1.24). CYP2D6 metabolism phenotype was associated with tamoxifen-induced hot flushes (P = .020). Both PM and IM phenotypes had an increased risk of tamoxifen-induced hot flushes compared with EM phenotype (PM vs EM, HR of hot flushes = 1.24, 95% CI = 0.96 to 1.59; IM vs EM, HR of hot flushes = 1.23, 95% CI = 1.05 to 1.43).ConclusionsCYP2D6 phenotypes of reduced enzyme activity were not associated with worse disease control but were associated with increased hot flushes, contrary to the hypothesis. The results of this study do not support using the presence or absence of hot flushes or the pharmacogenetic testing of CYP2D6 to determine whether to treat postmenopausal breast cancer patients with tamoxifen.

Project description:BackgroundEarlyR gene signature in estrogen receptor-positive (ER+) breast cancer is computed from the expression values of ESPL1, SPAG5, MKI67, PLK1, and PGR. EarlyR has been validated in multiple cohorts profiled using microarrays. This study sought to verify the prognostic features of EarlyR in a case-cohort sample from BIG 1-98, a randomized clinical trial of ER+ postmenopausal breast cancer patients treated with adjuvant endocrine therapy (letrozole or tamoxifen).MethodsExpression of EarlyR gene signature was estimated by Illumina cDNA-mediated Annealing, Selection, and Ligation assay of RNA from formalin-fixed, paraffin-embedded primary breast cancer tissues in a case-cohort subset of ER+ women (N = 1174; 216 cases of recurrence within 8 years) from BIG 1-98. EarlyR score and prespecified risk strata (≤25 = low, 26-75 = intermediate, >75 = high) were "blindly" computed. Analysis endpoints included distant recurrence-free interval and breast cancer-free interval at 8 years after randomization. Hazard ratios (HRs) and test statistics were estimated with weighted analysis methods.ResultsThe distribution of the EarlyR risk groups was 67% low, 19% intermediate, and 14% high risk in this ER+ cohort. EarlyR was prognostic for distant recurrence-free interval; EarlyR high-risk patients had statistically increased risk of distant recurrence within 8 years (HR = 1.73, 95% confidence interval = 1.14 to 2.64) compared with EarlyR low-risk patients. EarlyR was also prognostic of breast cancer-free interval (HR = 1.74, 95% confidence interval = 1.21 to 2.62).ConclusionsThis study confirmed the prognostic significance of EarlyR using RNA from formalin-fixed, paraffin-embedded tissues from a case-cohort sample of BIG 1-98. EarlyR identifies a set of high-risk patients with relatively poor prognosis who may be considered for additional treatment. Further studies will focus on analyzing the predictive value of EarlyR signature.

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Dataset Information

Obesity and risk of recurrence or death after adjuvant endocrine therapy with letrozole or tamoxifen in the breast international group 1-98 trial.

Purpose

Patients and methods

Results

Conclusion

Publications

Obesity and risk of recurrence or death after adjuvant endocrine therapy with letrozole or tamoxifen in the breast international group 1-98 trial.

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