Background and purpose: The risk of arm lymphedema in locally advanced breast cancer patients treated with neoadjuvant chemotherapy and local treatment (e.g.

surgical procedure and radiation therapy) has not been fully clarified so far. This study was conducted to retrospectively investigate the incidence of lymphedema and associated risk factors in patients treated with neo-adjuvant chemotherapy. Methods: A total of 103 breast cancer patients who underwent neo-adjuvant chemotherapy followed by surgery with axillary lymph node (ALN) dissection from Jan. 2007 to Dec. 2012 were retrospectively analyzed. All patients received postoperative breast/chest wall and supraclavicular field radiation therapy. The determination of lymphedema was based on arm circumference measurement. Results: At a median follow-up time of 4.5 years

41 patients developed lymphedema. The overall 4.5-year cumulative incidence of lymphedema was 39.8%. According to the analysis result

the number of dissected ALN15 ［hazard ratio (HR)=2.455; P=0.006］ and having full course of neo-adjuvant chemotherapy (HR=2.199; P=0.014) were independent risk factors for lymphedema. Conclusions: More than 1/3 of the patients in our setting developed lymphedema. Those who have the number of dissected ALN15 and full course of neo-adjuvant chemotherapy are more likely to develop lymphedema. Thus

more frequent surveillance are necessary for them to detect and treat lymphedema at an early stage.