As reported in the Journal of Clinical Oncology by Wapnir et al, the final analysis of the phase III CALOR trial showed benefit of adjuvant chemotherapy in estrogen receptor (ER)–negative but not ER-positive isolated locoregional recurrence of breast cancer.
In this open-label trial, patients with isolated locoregional recurrence of breast cancer were randomized between August 2003 and January 2010 to receive chemotherapy (selected by the investigator, multidrug for at least 3 months recommended) or no chemotherapy. Patients with hormone receptor–positive disease received adjuvant endocrine therapy. Radiation therapy was mandatory for patients with microscopically involved margins. Anti-HER2 therapy was optional.
At median follow up of 5 years, a significant benefit in disease-free survival was found for chemotherapy for ER-negative disease, with additional follow up required for ER-positive disease. The current report presents results at median follow-up of 9 years, focusing on ER status cohorts.
Outcome by ER Status
Among evaluable patients in the current analysis, 29 patients with ER-negative disease and 56 with ER-positive disease received chemotherapy, and 29 with ER-negative disease and 48 with ER-positive disease received no chemotherapy.
At median follow-up of 9 years, chemotherapy was associated with significant improvement in disease-free survival vs no chemotherapy among patients with ER-negative isolated locoregional recurrence (10-year rates = 70% vs 34%, hazard ratio [HR] = 0.29, 95% confidence interval [CI] = 0.13–0.67), but not among patients with ER-positive isolated locoregional recurrence (10-year rates = 50% vs 59%, HR = 1.07, 95% CI = 0.57–2.00). Breast cancer–free interval was also pronged by chemotherapy in patients with ER-negative isolated locoregional recurrence (breast cancer free at 10 years = 70% vs 34%, HR = 0.29, 95% CI = 0.13–0.67) but not in patients with ER-positive isolated locoregional recurrence (58% vs 62%, HR = 0.94, 95% CI = 0.47–1.85). Overall survival at 10 years was 73% vs 53% with vs without chemotherapy among patients with ER-negative isolated locoregional recurrence (HR = 0.48, 95% CI = 0.19–1.20) and 76% vs 66% among those with ER-positive isolated locoregional recurrence (HR = 0.70, 95% CI = 0.32–1.55). Interaction tests comparing chemotherapy effect for ER-positive isolated locoregional recurrence vs ER-negative isolated locoregional recurrence were P = .013 for interaction for disease-free survival, P = .034 for interaction for breast cancer–free interval, and P = .53 for interaction for overall survival.
The investigators concluded, “The final analysis of CALOR confirms that [chemotherapy] benefits patients with resected ER-negative [isolated locoregional recurrence of breast cancer] and does not support the use of [chemotherapy] for ER-positive [isolated locoregional recurrence].”
The CALOR trial was supported in part by Public Service Grants from the National Cancer Institute.
Stefan Aebi, MD, of Lucerne Cantonal Hospital, is the corresponding author of the Journal of Clinical Oncology article.
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