BACKGROUND: Although chronic postsurgical pain (CPSP) after breast cancer surgery is a common and prevalent postsurgical adverse event, the need for CPSP treatment has not been investigated. This study examined the proportion of patients who needed treatment for CPSP and associated predictors. METHODS: We conducted a cross-sectional study with female patients who underwent breast cancer surgery at our institution. Participants were aged ≤ 65 years at the time of this study and were at least 1 year post surgery. The questionnaire examined the presence of and need for treatment for CPSP and included the Japanese version of the Concerns about Recurrence Scale (CARS-J). Multivariate analyses were used to identify independent predictors of needing treatment for CPSP. RESULTS: In total, 305 patients completed the questionnaire. The mean time since surgery was 67.1 months; 156 (51%) patients developed CPSP after breast cancer surgery and 61 (39%) needed treatment for CPSP. Among patients that developed CPSP, the fear of breast cancer recurrence as assessed by the CARS-J (odds ratio [OR] 2.59, 95% confidence interval [CI] 1.14-6.28, P = 0.028) and ≥ 2 postsurgical pain regions (OR 2.52, 95% CI 1.16-5.57, P = 0.020) were independent predictors of needing treatment for CPSP. CONCLUSIONS: This study is the first to identify the proportion and predictors of patients who need treatment for CPSP. Fear of breast cancer recurrence and ≥ 2 postsurgical pain regions may predict the need for CPSP treatment among patients following breast cancer surgery.