Session Item

Adjuvant radiation therapy for locally advanced breast cancer is part of the standard treatment to reduce local recurrence and death rates. Acute radiodermatitis is one of the most common side effects and bolus is a known predictive factor of it. In clinical practice many centers are hesitating to use bolus with hypofractionation. The purpose of this study is to show the effect of bolus in acute radiodermatitis in breast cancer patients treated with moderately hypofractionated radiation therapy.

In our prospective study we enrolled all T4 breast cancer patients treated with moderately hypofractionated radiation therapy (40Gy/15 fractions) after mastectomy. From 2016 to 2021 a total of 168 patients were irradiated at our Oncology Service. Standard 3D-CRT technique was used and a bolus of 5mm was applied daily. Chemotherapy was administered to all patients. Acute toxicity was evaluated using the RTOG scale. We monitored patients during radiation therapy, at the end of treatment, two weeks, one month, and two months after radiation therapy.

The median age of the series was 54 years (range 31-83). Histology was invasive ductal carcinoma (90%), invasive lobular carcinoma (6%), and mixt (4%). The rates of acute grade 1, grade 2, and grade 3 radiodermatitis was 28% (n=47), 7% (n=12), and 4% (n=7), respectively. No treatment interruption was recorded. We did not find any significant correlation between chemotherapy regimen, endocrine therapy, nodal irradiation, higher BMI, or any other patient comorbidity, and higher grade of radiodermatitis.

In our experience the use of bolus in patients with locally advanced breast cancer receiving moderately hypofractionated radiation therapy was overall safe, well tolerated, and associated with mild toxicity.