Comparative retrospective analysis of locoregional recurrence in unselected breast cancer patients treated with conventional versus hypofractionated radiotherapy at a tertiary cancer center?

ABSTRACT

BACKGROUND: Role of hypofractionated radiotherapy (HFRT) in early breast cancer is established; comparatively, there are limited data for HFRT in locally advanced breast cancer (LABC). We report the impact of HFRT in unselected breast cancer patients in comparison with historically treated patients with conventional fractionated radiotherapy (CFRT). PATIENTS AND METHODS: Records of 463 breast cancer patients treated between January 09 and July 13 with CFRT (50 Gy/25 fr) or HFRT (42.4 Gy in 16 fractions or 40 Gy in 15 fractions) in two sequential periods were retrospectively reviewed. The analysis was done in August 2018. The primary endpoint was to compare the differences in locoregional recurrence rate. RESULTS: Of the 463 patients, 209 received CFRT and 254 received HFRT. The median age was 48 years (interquartile range 40-56), premenopausal (CFRT 23% vs. HFRT 39%, P = 0.005). The most common pathology was infiltrating ductal carcinoma (81%) with Grade III tumors (45%), estrogen receptor (+) was seen in 44%, triple-negative breast cancer in 34%, and Her2Neu (3+) were seen in 27%. Two hundred and fifty-four patients (54.5%) had undergone breast-conserving surgery (BCS) and 209 patients (45%) modified radical mastectomy (MRM). Nodal radiotherapy was delivered in 76% versus 64% in patients receiving CFRT versus HFRT, respectively (P = 0.005). With a median follow-up of 46 months in CFRT and 57 months in HFRT, 9/209 (4.3%) patients in CFRT and 7/254 (2.7%) in HFRT had locoregional relapse (LRR). The 4 years#39; actuarial local recurrence-free survival (LRFS) in CFRT versus HFRT was 95% versus 97% (P = 0.37). The mean estimated LRFS (local relapse-free survival) for CFRT is 113.4 months and for HFRT 94.2 months (P = 0.3). CONCLUSIONS: The risk of local recurrence among patients of breast cancer treated with HFRT after BCS or MRM was not worse when compared to CFRT.