-
Views
-
Cite
Cite
Miwako Nozaki, Yoshikazu Kagami, Taro Shibata, Kenichi Nakamura, Yoshinori Ito, Yasumasa Nishimura, Yoshifumi Kawaguchi, Yoshihiro Saito, Yasushi Nagata, Yasuo Matsumoto, Tetsuo Akimoto, Masahiro Hiraoka, Radiation Therapy Study Group, Japan Clinical Oncology Group, A primary analysis of a multicenter, prospective, single-arm, confirmatory trial of hypofractionated whole breast irradiation after breast-conserving surgery in Japan: JCOG0906, Japanese Journal of Clinical Oncology, Volume 49, Issue 1, January 2019, Pages 57–62, https://doi.org/10.1093/jjco/hyy160
Close - Share Icon Share
Abstract
To evaluate the safety of hypofractionated whole breast irradiation in Japanese women after breast-conserving surgery.
Japanese women who had invasive breast cancer with a clinical tumor size ≤3 cm, pN0-1c and a negative inked margin were enrolled. Hypofractionated whole breast irradiation (42.56 Gy/16 fractions) was delivered, adding boost irradiation (10.64 Gy/4 fractions) when the surgical margin was ≤5 mm. The treatment course was meant to be completed within 29 days or 33 days (plus boost irradiation). The primary endpoint was the proportion of grade ≥2 of pre-specified late adverse reactions, including telangiectasia, ulceration, fibrosis, fracture, pneumonitis, cardiac ischemia/infarction, pericardial effusion and breast pain, within 3 years. A sample size of 310 patients was set, with one-sided alpha of 0.05, beta of 0.1, threshold value of 8% and expected value of 4%. Secondary endpoints included the proportion of treatment completion within the recommended period and early adverse events within 90 days. Adverse events/adverse reactions were evaluated using CTCAE-3.0.
Between 2010 and 2012, 312 women were enrolled; 306 received hypofractionated whole breast irradiation, but 6 chose conventional fractionated WBI, with 301 patients (96.5%) treated within the recommended period. Grade 2 early adverse events were found in 38 patients (12.4%); none had grade 3/4. Among the 303 evaluable patients, 13 (4.3%; 90% CI 2.6–6.7) had grade 2/3 late adverse reactions, including one with grade 3 pneumonitis, which was under the threshold value.
Hypofractionated whole breast irradiation is considered to be safe and one of the standard treatments for Japanese women with margin-negative invasive breast cancer after breast-conserving surgery.
