Miwako Nozaki1, Yoshikazu Kagami2, Taro Shibata3, Kenichi Nakamura3, Yoshinori Ito2,4, Yasumasa Nishimura5, Yoshifumi Kawaguchi6, Yoshihiro Saito7, Yasushi Nagata8, Yasuo Matsumoto9, Tetsuo Akimoto10, Masahiro Hiraoka11,12. 1. Saitama Medical Center, Dokkyo Medical University, Saitama, Japan. 2. School of Medicine, Showa University Tokyo, Japan. 3. National Cancer Center Hospital, JCOG Data Center/Operation Office Tokyo, Japan. 4. National Cancer Center Hospital Tokyo, Japan. 5. Faculty of Medicine, Kindai University Osaka, Japan. 6. Osaka International Cancer Institute Osaka, Japan. 7. Saitama Cancer Center Saitama, Japan. 8. Graduate School of Biomedical Science, Hiroshima University Hiroshima, Japan. 9. Niigata Cancer Center Hospital Niigata, Japan. 10. National Cancer Center Hospital East Chiba, Japan. 11. Graduate School of Medicine, Kyoto University Kyoto, Japan. 12. Japanese Red Cross Wakayama Medical Center, Wakayama, Japan.
Abstract
OBJECTIVE: To evaluate the safety of hypofractionated whole breast irradiation in Japanese women after breast-conserving surgery. METHODS: 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. RESULTS: 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. CONCLUSION: 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.
OBJECTIVE: To evaluate the safety of hypofractionated whole breast irradiation in Japanese women after breast-conserving surgery. METHODS: 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. RESULTS: 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. CONCLUSION: 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.