- Adjuvant chemotherapy is associated with up to 42% survival benefit vs no chemotherapy in patients aged ≤70 years with node-negative breast cancer who have the high end of intermediate 21-gene recurrence scores (RS) of 26-30, according to an analysis of the Surveillance Epidemiology and End Results (SEER) database.
- Chemotherapy has greatest benefit for younger patients or those with grade III tumors.
Why this matters
- This is the first study of chemotherapy in patients with this subset of intermediate RS.
- Prior studies of the lower end of intermediate RS (16-25) found no chemotherapy benefits.
- Retrospective cohort of 29,137 US patients with RS 26-30 (2004-2015) in SEER database.
- Funding: None.
- Mean follow-up was 32 months.
- Patients with RS 26-30 (vs patients with RS 18-25) had higher breast cancer-specific mortality (HR, 1.81; 95% CI, 1.46-2.26) and higher mortality (HR, 1.37; 95% CI, 1.19-1.58) after adjusting for treatments and other confounders.
- Receipt of adjuvant chemotherapy by patients with RS 26-30 (vs no chemotherapy) was associated with 32% lower breast cancer-specific mortality (HR, 0.68; 95% CI, 0.47-0.99) and 42% lower mortality (HR, 0.58; 95% CI, 0.44-0.76).
- Subgroup analysis found higher chemotherapy benefits for younger patients ≤56 years (log-rank P=.046) or those with grade III tumors (log-rank P=.003).
- Retrospective observational design.