women with low-risk tumors. In a multivariable Cox proportional hazards
model, chemotherapy use was not associated with improved
cancer-specific (HR = 1.62; 95% CI, 0.74–3.56) or overall (HR = 0.93;
95% CI, 0.65–1.33) survival (Table 4). Among high-risk patients, the administration
of chemotherapy was associated with improved overall
survival (HR=0.70; 95% CI, 0.53–0.91) but not cancer-specific survival
(HR=0.89; 95% CI, 0.59–1.35). Fig. 2A displays a Kaplan–Meier analysis
of overall survival for high-risk patients stratified by the receipt of chemotherapy
(log-rank P b 0.001).
When the duration of chemotherapy was analyzed among high-risk
patients, we noted that 215 (44.2%) women received ≤3 months of
treatment while 271 (55.8%) received 4–8 months of chemotherapy.
Advanced stage was the strongest predictor of extended duration chemotherapy.
Women with stage IC tumors were more likely to receive