Chronic pain after major breast surgery

BACKGROUND Breast surgery is a cornerstone in the treatment of breast cancer but can cause persistent or worsening pain lasting beyond 3 months. Perioperative risk factors for chronic pain remain an area of ongoing research. OBJECTIVE To assess the incidence of chronic pain following breast surgery and identify its associated factors. DESIGN A retrospective cohort study. SETTING A single high-volume tertiary medical centre. PATIENTS Women undergoing first-time unilateral breast surgery as part of breast cancer treatment, without pre-existing chronic pain, between January 2020 and September 2022. MAIN OUTCOME MEASURES The incidence of chronic postoperative pain at 3 and 6 months, pain scores, perioperative and in-hospital analgesic use, and predictive factors related to anaesthetic and treatment modalities. METHODS Univariable and multivariable analysis of peri-operative data associated with chronic postoperative pain at 3 and 6 months. A multivariable model was constructed by stepwise selection of data. RESULTS Chronic pain was reported in 32% (95% confidence interval (CI), 28.8 to 35.4%) of patients at 3 months and in 39% (95% CI, 35.9 to 42.2%) at 6 months postoperatively. During postanaesthetic care, 31% of patients recorded a pain score above four on the numeric rating scale (NRS), while 3% reported a score above seven. On subsequent days, the mean pain score fell below one. The use of sufentanil and propofol during general anaesthesia was strongly associated with a lower incidence of pain at 3 months, odds ratio (OR) 0.548 (95% CI 0.381 to 0.788) P = 0.0012, as well as sentinel node biopsy, OR 0.520 (95% CI 0.274 to 0.988) P = 0.0459. Adjuvant radiotherapy, OR 3.294 (95% CI 1.610 to 6.741) P = 0.0011, and the presence of chronic pain at 3 months, OR 10.706 (95% CI 7.399 to 15.489) P < 0.0001, were the strongest predictors of persistent pain at 6 months. Mastectomy, OR 0.610 (95% CI 0.456 to 0.817) P = 0.0009, and age, OR 0.983 (95% CI 0.972 to 0.995) P = 0.0051, were significantly associated after model construction. CONCLUSIONS Multiple factors are associated with chronic pain following breast surgery. While perioperative factors play a role, long-term treatment modalities also significantly influence its occurrence.