Acute radiation dermatitis and pneumonitis in Japanese breast cancer patients with whole breast hypofractionated radiotherapy compared to conventional radiotherapy.

Objective: To evaluate acute morbidity, radiation dermatitis and pneumonitis, of Japanese patients treated with whole breast hypofractionated radiotherapy (RT) after breast-conserving surgery (BCS), compared to conventional RT.

Methods: Japanese patients who received whole breast RT after BCS between October 2003 and September 2006 were retrospectively reviewed. Patients who had selected the conventional or hypofractionated schedule received whole breast irradiation of 50 Gy in 25 fractions plus boost or 40 Gy in 16 fractions plus boost. Radiation dermatitis and symptomatic pneumonitis were graded according to the Common Terminology Criteria for Adverse Events version 3.0.

Results: Of 443 consecutive patients, 377 (85%) received the conventional schedule and 66 (15%) received the hypofractionated schedule. Of patients treated with the conventional schedule, Grade 0, 1, 2 and 3 radiation dermatitis were observed in 16 (4%), 278 (74%), 77 (20%) and 6 (2%), respectively. Of patients treated with the hypofractionated schedule, Grade 0, 1, 2 and 3 dermatitis were observed in 11 (17%), 49 (74%), 5 (8%) and 1 (1%), respectively. Grade 2-3 dermatitis by the hypofractionated schedule (9%) was observed less frequently than that by the conventional schedule (22%) (chi-square test; P = 0.016). Moreover, of patients treated with the conventional schedule, 4 (1%) had Grade 2 radiation pneumonitis. No patient treated with the hypofractionated schedule had symptomatic pneumonitis.

Conclusions: Radiation dermatitis and pneumonitis in Japanese patients treated with the hypofractionated schedule is acceptable. Especially, radiation dermatitis by the hypofractionated schedule is milder than that by the conventional schedule.