Results. We identified 1394 patients. Among low-risk patients, 32.9% received adjuvant chemotherapy and
the use of chemotherapy increased with time. Among high-risk patients, 71.9% received adjuvant chemotherapy;
44.2% had ≤3 months of treatment, and 55.8% had N3 months of treatment. Older patients were less likely to receive
chemotherapy, while those with higher stage and grade were more likely to receive chemotherapy
(P b 0.05 for all). Among high-risk patients, the duration of chemotherapy did not impact overall (HR = 0.93,
95% CI, 0.67–1.27) or cancer specific (HR = 0.93; 95% CI, 0.61–1.42) survival.