Adjuvant chemotherapy does not reduce the number of disease-free survival events among patients with ER-positive breast cancer after isolated locoregional recurrence (ILRR), according to a study published in the Journal of Clinical Oncology.1

ILRR occurs at a relatively low rate but is strongly associated with mortality. The randomized phase 3 CALOR trial (Chemotherapy as Adjuvant for LOcally Recurrent Breast Cancer; ClinicalTrials.gov Identifier: NCT00074152) showed that patients with ER-negative disease may benefit from adjuvant chemotherapy after ILRR. It was unknown, however, whether patients with ER-positive disease would benefit from this strategy.

For the present report, researchers published the 9-month follow-up data from CALOR. Patients were stratified by ER status: of 58 patients with ER-negative disease, 29 were assigned each to chemotherapy and to no chemotherapy; of 104 patients with ER-positive disease, 56 were assigned to chemotherapy and 48 to no chemotherapy.

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Patients in the ER-negative cohort had a median time to ILRR from primary cancer of 3.6 years. Patients in the ER-positive cohort, however, had a median time to ILRR of 6.8 years. All but 6% of patients in the ER-positive cohort previously received endocrine therapy.

Disease-free survival (DFS) events occurred at the highest rate among patients with ER-negative disease who did not receive chemotherapy (19 events, 66%), and at the lowest rate among those with ER-negative disease who received chemotherapy (8 events, 28%).

Chemotherapy did not, however, reduce the likelihood of a DFS event among patients with ER-positive disease (22 events, 39% vs 18 events with no chemotherapy, 38%). In the ER-positive cohort, the 10-year DFS rates were 50% with chemotherapy and 59% without.

The 10-year overall survival rate was improved in ER-negative patients who received chemotherapy (73% vs 53% without; hazard ratio, 0.48). The 10-year overall survival rates in the ER-positive group were 76% with chemotherapy vs 66% without (hazard ratio, 0.70).

The authors concluded that “[chemotherapy] offers the best prospect of prolonged DFS in patients with ER-negative first ILRR, whereas adding CT to endocrine therapy seems to offer no benefit to patients with ER-positive ILRR.”

Reference

  1. Wapnir IL, Price KN, Anderson SJ, et al. Efficacy of chemotherapy for ER-negative and ER-positive isolated locoregional recurrence of breast cancer: final analysis of the CALOR trial. J Clin Oncol. 2018 Feb 14. doi: 10.1200/JCO.2017.76.5719 [Epub ahead of print]