Purpose: Experimental data suggest a complex cross-talk between HER-2 and estrogen receptor, and it has been hypothesized that HER-2-positive tumors may be less responsive to certain endocrine treatments. Clinical data, however, have been conflicting. We have conducted a metaanalysis on the interaction between the response to endocrine treatment and the overexpression of HER-2 in metastatic breast cancer. Experimental Design: Studies have been identified by searching the Medline, Embase, and American Society of Clinical Oncology abstract databases. Selection criteria were (a) metastatic breast cancer, (b) endocrine therapy (any line of treatment), and (c) evaluation of HER-2 expression (any method). For each study, the relative risk for treatment failure for HER-2-positive over HER-2-negative patients with 95% confidence interval was calculated as an estimate of the predictive effect of HER-2. Pooled estimates of the relative risk were computed by the MantelHaenszel method. Results: Twelve studies (n = 2,379 patients) were included in the meta-analysis. The overall relative risk was 1.42 (95% confidence interval, 1.32-1.52; P < 0.00001; test for heterogeneity = 0.380). For studies involving tamoxifen, the pooled relative risk was 1.33 (95% confidence interval, 1.20-1.48; P < 0.00001; test for heterogeneity = 0.97); for studies involving other hormonal drugs, a pooled relative risk of 1.49 (95% confidence interval, 1.36-1.64; P < 0.00001; test for heterogeneity = 0.08) was estimated. A second meta-analysis limited to tumors that were either estrogen receptor positive, estrogen receptor unknown, or estrogen receptor negative/progesterone receptor positive yielded comparable results. Conclusions: HER-2-positive metastatic breast cancer is less responsive to any type of endocrine treatment. This effect holds in the subgroup of patients with positive or unknown steroid receptors.
BackgroundAt the time of the initial analysis of overall survival (OS) for the Comparison of Faslodex in Recurrent or Metastatic Breast Cancer (CONFIRM) randomized, double-blind, phase III trial, approximately 50% of patients had died. A final analysis of OS was subsequently planned for when 75% of patients had died.MethodsPatients were randomly assigned 1:1 to fulvestrant 500 mg administered as two 5-mL intramuscular injections on days 0, 14, and 28 and every 28 (±3) days thereafter or fulvestrant 250 mg administered as two 5-mL intramuscular injections (one fulvestrant and one placebo [identical in appearance to study drug]) on days 0, 14 (two placebo injections only), and 28 and every 28 (±3) days thereafter. OS was analyzed using an unadjusted log-rank test. No adjustments were made for multiplicity. Serious adverse events (SAEs) and best response to subsequent therapy were also reported. All statistical tests were two-sided.ResultsIn total, 736 women (median age = 61.0 years) were randomly assigned to fulvestrant 500mg (n = 362) or 250mg (n = 374). At the final survival analysis, 554 of 736 (75.3%) patients had died. Median OS was 26.4 months for fulvestrant 500mg and 22.3 months for 250mg (hazard ratio = 0.81; 95% confidence interval = 0.69–0.96; nominal P = .02). There were no clinically important differences in SAE profiles between the treatment groups; no clustering of SAEs could be detected in either treatment group. Type of first subsequent therapy and objective responses to first subsequent therapy were well balanced between the two treatment groups.ConclusionsIn patients with locally advanced or metastatic estrogen receptor–positive breast cancer, fulvestrant 500mg is associated with a 19% reduction in risk of death and a 4.1-month difference in median OS compared with fulvestrant 250mg. Fulvestrant 500mg was well tolerated, and no new safety concerns were identified.
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