Abstract
Most new cases and the highest mortality rates of breast cancer occur among middle-aged and old women. The recurrence rate of early-stage invasive ductal carcinoma (IDC) among women aged ≥ 50 years and receiving different treatments remains unclear. Therefore, this study was conducted to determine these rates. We used Surveillance, Epidemiology, and End Results (SEER) data for this nationwide population-based cohort study. All women aged ≥ 50 years and diagnosed with early-stage IDC between 2000 and 2015 were identified and divided into three treatment groups, namely, breast conservation therapy (BCT), mastectomy alone (MAS), and mastectomy with radiation therapy (MAS + RT). The recurrence rates of IDC among these groups were then compared. The BCT group had a lower short-term recurrence risk than the MAS and MAS + RT groups (hazard ratio [HR]: 1.00 vs. 2.90 [95% CI 1.36-2.66] vs. 2.07 [95% CI 0.97-4.44]); however, the BCT group also had a higher long-term recurrence risk than MAS and MAS + RT groups (HR 1.00 vs. 0.30 [95% CI 0.26-0.35] vs. 0.43 [95% CI 0.30-0.63]). The high long-term recurrence rate of the BCT group was especially prominent at the 10- and 15-year follow-ups. The results provide valuable evidence of the most reliable treatment strategy for this population. Further studies including more variables and validation in other countries are warranted to confirm our findings.