Post-operative loco-regional (LR) hypofractionated radiotherapy (Hypo-RT) is an attractive approach in locally advanced breast cancer (LABC).

The present is a single arm phase II study assessing toxicity levels after 34 Gy/10 fxs/2 wks to the whole breast/chest wall and to the draining lymph nodes; an optional single fraction 8 Gy boost was administered with electrons to the tumor bed in patients who had undergone conservative surgery. Both acute (CTCAE v4.0) and late (LENT/SOMA) toxicity were collected. All pts but those who underwent mastectomy without reconstruction or with temporary expander were also asked to rate their cosmetic outcome according to the Harvard. Toxicity was assessed weekly during RT and then at each follow-up examination (1, 3, 6 months and then yearly).

Inclusion Criteria:

• Patients affected by invasive breast cancer who underwent conservative breast surgery or mastectomy and axillary dissection, followed by post operative radiotherapy at the level of the breast/chest wall, and of the supraclavicular, third axillary level +/- internal mammary chain nodes.
• pT1-3 disease pN1-2, cT1-3 disease if neoadjuvant chemotherapy , cN + cytologically and/or histologically assessed;
• ECOG Performance status ≤2;
• histologically negative surgical margins
• no distant metastases
• no prior chest radiotherapy
• life expectancy ≥ 5 years
• no prior cancer

Exclusion Criteria:

• Non-epithelial breast cancer (sarcoma, lymphoma etc.)
• Metastases at the level of the internal chain mammary and / or supra-clavicular lymph nodes histologically assessed
• pT4 neoplasms or inflammatory breast carcinoma
• Distant metastasis
• Concomitant chemotherapy
• history of prior controlateral breast tumor

The study population included breast cancer patients with nodal involvement who underwent conservative surgery or mastectomy, followed by post operative locoregional radiotherapy after conservative surgery or mastectomy.