Adjuvant Radiotherapy is Associated with an Increase of Survival of Old (Aged Over 80 Years) and Very Old (Aged Over 90 Years) Women with Breast Cancer Receiving Breast-Conserving Surgery

BACKGROUND: To date,no data on the effect of adjuvant whole-breast radiotherapy (WBRT) on oncologic outcomes, such as all-cause death, locoregional recurrence (LRR), and distant metastasis (DM), are available forold (aged ≥80 years) and very old (≥90 years) women with breast invasive ductal carcinoma (IDC) receiving breast-conserving conservative surgery (BCS).PATIENTS AND METHODS: We enrolled old (≥80 yearsold) and very old (≥90 yearsold) women with breast IDC who had received BCS followed by adjuvant WBRT or no adjuvant WBRT. We groupedthem based on adjuvant WBRT status and compared their overall survival (OS), LRR, and DM outcomes. To reduce the effects of potential confounders when comparing all-cause mortality between the groups, propensity score matching was performed.RESULTS:Overall, 752 older women with IDC received BCS followed by adjuvant WBRT, and 752 with IDC received BCS with no adjuvant WBRT.In multivariable Cox regression analysis, the adjusted hazard ratio (aHR) and 95% confidence interval (95% CI) of all-cause death for adjuvant WBRT compared with no adjuvant WBRT in older women with IDC receiving BCS was 0.56 (0.44-0.70). The aHRs (95% CIs) of LRR and DM foradjuvant WBRT were 0.29 (0.19-0.45) and 0.45 (0.32-0.62), respectively, compared with no adjuvant WBRT.CONCLUSION: Adjuvant WBRT was associated with decreases in all-cause death, LRR, and DM in old (aged ≥80 years) and very old (aged ≥90 years) women with IDC compared with no adjuvant WBRT.Condensed Abstract: This study is the first to examine the effect of adjuvant whole-breast radiotherapy (WBRT) on oncologic outcomes such as all-cause death, locoregional recurrence (LRR), and distant metastasis (DM) in old (aged ≥80 years) and very old (aged ≥90 years) women with breast invasive ductal carcinoma (IDC) receiving breast-conserving surgery. After propensity score matching, adjuvant WBRT was associated with decreases in all-cause death, LRR, and DM in old and very old women with IDC compared with no use of adjuvant WBRT.