Researchers examined data from 1,110 patients at two major medical centers who had stage IIIC locally advanced breast cancer or de novo oligometastatic disease. Many of these patients also had contralateral axillary metastasis, meaning cancer spread to the armpit on the side opposite the original tumor. The team compared outcomes for those receiving curative-intent local therapy, such as surgery or radiotherapy, against those managed with a systemic therapy-focused approach.
The analysis showed that patients receiving local therapy had a significantly lower adjusted mortality risk compared to those with de novo oligometastatic disease. In a specific matched analysis, local therapy was associated with a 51% reduction in mortality risk. Additionally, the five-year rate of locoregional recurrence was lower in the treatment group, dropping from 31.4% to 12.1%.
While the results are consistent across different statistical methods, this study has important limitations. It is a retrospective cohort study, meaning the data was reviewed after the fact rather than from a planned experiment. This design makes it difficult to rule out other factors that might have influenced survival. Readers should understand that this evidence supports re-evaluating how we treat these specific metastases but does not yet prove local therapy is a standard solution for everyone.