Introduction: Chronic post-mastectomy pain is a common and disabling survivorship problem, and growing evidence suggests that early postoperative inflammation may contribute to its development. C-reactive protein is an accessible biomarker of surgical inflammatory response. This study aimed to evaluate whether first-postoperative-day C-reactive protein levels are associated with subsequent chronic post-mastectomy pain.

Material and methods: This descriptive cross-sectional study was conducted at Tabriz University of Medical Sciences in 2022 on 50 women undergoing mastectomy, selected by convenience sampling. Sample size was estimated using the Cochran single-group formula. The main variables included first-postoperative-day serum C-reactive protein level and chronic post-mastectomy pain at follow-up, alongside demographic, clinical, surgical, oncologic, and postoperative variables potentially related to pain development.

Results: Among 50 women undergoing mastectomy, 19 (38.0%) developed chronic post-mastectomy pain. Mean first-postoperative-day CRP was significantly higher in patients with chronic pain than in those without pain (36.2 ± 11.6 vs 23.9 ± 8.7 mg/L, P < 0.001). Axillary lymph node dissection (84.2% vs 54.8%, P = 0.034), longer operative time (127.9 ± 25.1 vs 109.8 ± 21.6 minutes, P = 0.011), and early postoperative complications (36.8% vs 12.9%, P = 0.046) were also associated with pain development.

Conclusion: Elevated first-postoperative-day CRP was independently associated with chronic post-mastectomy pain, suggesting that an intensified early postoperative inflammatory response may play an important role in pain chronification after breast cancer surgery.