Background or objectives: Breast cancer is the most frequent cancer in women. Chronic pain following mastectomy remains a significant problem. This study aimed to evaluate risk factors associated with postoperative chronic pain.

Methods: Medical records were analyzed retrospectively for 147 consecutive patients with breast cancer who underwent mastectomy between July 2016 and February 2018 with one-year follow-up. All patients received a paravertebral block pre-operatively and then general anesthesia for the surgery.

Results: The median postoperative pain score was 1.3 on the verbal analgesic score. The average total dose of opioids administered postoperatively was 10.4 mg, expressed in morphine milligram equivalents. The incidence of chronic pain after mastectomy was 16.7% at 6 months and 13.3% at 1 year. The satisfaction rate for anesthesia and surgery was 95.7%.

Conclusions: The data suggested that preoperative paravertebral nerve blocks, appropriate adjuvants, and a balanced general anesthetic may contribute to better postoperative pain control and decreased the incidence of chronic pain. A history of preoperative use of opioids and/or a history of alcohol consumption were both associated with significant increased levels of postoperative pain, and this subgroup warrants attention to diminish the risk of developing chronic pain.

Keywords: breast cancer; chronic pain; paravertebral nerve block; postoperative pain; postoperative pain management.