Eurasian Journal of Chemical, Medicinal and Petroleum Research 2980-9347 5 4 2026 10 17 Association of First-Postoperative-Day C-Reactive Protein Levels with Early Postoperative Inflammatory Response After Mastectomy 314 322 247294 10.5281/zenodo.21432798 EN Seyed Vahid Seyed Hoseini Assistant Professor of Surgery, Department of General Surgery, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran 0009-0002-1365-3038 Mansour Rezaei Associate Professor of Anesthesiology, Department of Anesthesiology, School of Medicine, Tabriz, Iran. 0000-0002-3196-000X Journal Article 2026 04 20 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.<br><br>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.<br><br>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.<br><br>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. https://www.ejcmpr.com/article_247294_60343a7320549aa13bf9a10c468c2ada.pdf