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The aim of this study was to assess early outcomes and safety of hypofractionated radiotherapy in non-metastatic locally advanced stage T4 breast cancer.

Fifty patients irradiated between 2017 and 2020 for non-metastatic locally advanced stage T4 breast cancer (BC) were retrospectively evaluated. All patients underwent 3D conformal hypofractionated radiotherapy: 40 Gy delivered in 15 daily fractions of 2.67 Gy +/- additional boost of 13.35 Gy. Disease free survival, metastasis free survival, acute and late radiation induced toxicity were evaluated.

The mean age at diagnosis was 53 (33-77) years. Thirteen (26%) patients had inflammatory BC and 37 had stage T4b BC. All patients underwent chemotherapy which was neo-adjuvant in 76% of cases. Mastectomy was performed for 96% of patients, whereas two patients had conservative surgery. Regional lymph nodes irradiation was performed for 47 (94%) of patients. Additional boost to the thoracic wall/tumor bed was delivered in 40% of cases. Eighty percent of patients experienced acute skin toxicity with 66% of grade 1 radiation dermatitis and 14% of grade 2 radiation dermatitis. No grade 3-4 radiation dermatitis was reported. Sixteen patients reported dysphagia which was well managed with non-steroidal anti-inflammatory drugs. The median follow-up was 20 (2-40) months. Late skin toxicity was observed in 48% of patients with 36% of skin colour change and 12% of radiation induced fibrosis. Twenty-six (52%) did not report any late cutaneous toxicity. Local recurrence was observed in 4 women. The mean time to local failure was 13 months. Nine patients (18%) had distant metastatic failure. Disease free survival at 36 months was 87.8% whereas metastasis free survival was 82.8%.

Early outcomes of hypofractionated radiotherapy for stage T4 breast cancer seemed comparable to conventional breast cancer radiotherapy. Considering the important socio-economic impact, this may encourage its use in low middle income countries. Nonetheless, safety and efficacy of hypofractionated radiotherapy in locally advanced breast cancer need to be further studied in larger cohort.