Abstract
BACKGROUND/AIM: This study aimed to assess the time advantages of delivering adjuvant hypofractionated radiotherapy (AH-RT) before third-generation adjuvant chemotherapy (A-CT), compared to the standard sequence (A-CT before AH-RT), in node-positive breast cancer (BC). PATIENTS AND METHODS: A total of 45 patients with node-positive BC treated with AH-RT before third-generation A-CT at our institution between 2022 and 2023 (EXP group) were retrospectively enrolled and matched with a control group of 45 patients treated with standard sequencing (CTRL group). The primary endpoints were as follows: gain in time to RT initiation and overall treatment time, RT delay, RT interruptions, which were compared between the two groups. Propensity score matching was performed. Univariate and multivariate Cox-proportional hazards models were generated. Data from the multivariate analysis were confirmed by Pearson's covariance test, assuming p<0.001. RESULTS: A significant reduction in the time to AH-RT initiation and overall adjuvant treatment time was recorded in the EXP group. In the EXP group, the mean duration of the entire adjuvant treatment was 35 (29-40) weeks after surgery vs. 42 (39-50) weeks for the CTRL group (p=0.032). Hematological G2-G3 toxicity was responsible for RT delay (p=0.022) in the CTRL group. Multivariate analysis confirmed that acute skin toxicity was significantly associated with RT delay and interruption in the AH-RT15 CTRL arm (p=0.033) in the CTRL group. Pearson's covariance test confirmed these effects for the CTRL group (p<0.001). CONCLUSION: Treatment with AH-RT before third-generation A-CT was found to be safe with a low acute toxicity profile in node-positive breast cancer, providing an advantage in shortening the time from surgery to AH-RT initiation as well as the overall adjuvant treatment time.