Survival, progression, and HRQOL
At a median follow-up of 53 months, the median overall survival was 54 months in each arm. There was no significant difference in survival between the study arms, with superimposable survival curves (hazard ratio, 1.09; P = .63).
An analysis of overall survival by tumor type showed that, for the 20 women with triple-negative disease, survival was worse with early local therapy (HR, 3.50). There were no differences in survival either for the 79 patients with HER2-positive disease or for the 137 patients with hormone receptor–positive/HER2-negative disease.
Locoregional progression occurred in 25.6% of patients assigned to continued systemic therapy, compared with 10.2% assigned to early local therapy. However, progression-free survival was virtually identical between the study arms (P = .40).
At most time points, there were no significant between-arm differences in HRQOL. The exception was at 18 months of follow-up, when the HRQOL was significantly lower among patients who had undergone early local therapy (P = .001).
“Based on available data, locoregional therapy for the primary tumor should not be offered to women with stage IV breast cancer with the expectation of a survival benefit. When systemic disease is well controlled with systemic therapy but the primary site is progressing, as does happen occasionally, locoregional treatment can be considered,” Dr. Khan concluded.
She noted there is an ongoing trial of similar design in Japan (JCOG-1017), with results expected in 2022.
The current trial was supported by the National Cancer Institute and Canadian Cancer Society. Dr. Khan reported no conflicts of interest. Dr. White reported institutional research funding from Intraop Medical.
SOURCE: Khan SA et al. ASCO 2020, Abstract LBA2.