391: Psychophysiological Predictors of Acute and Long-Term Pain Following Gender Affirming Top Surgery

Topic: Clinical Science
Subtopic: Pain category (ICD-11), Acute postsurgical pain, Gender/sex differences, Quantitative Sensory testing (static and dynamic, e.g., HPT, PPT, CPM, TSP, offset analgesia), Pain in special populations (e.g. neonates, children, teens, elderly, neurodegenerative diseases)

Background and Aims: Gender-affirming top surgery aligns chest aesthetics with gender identity and significantly improves quality of life. However, post-operative pain outcomes are understudied in gender diverse populations. Broader literature suggests that 20–30% of ciswomen undergoing prophylactic mastectomy develop chronic post-mastectomy pain. Established predictors of worse post-surgical pain include pre-operative anxiety, pain catastrophizing, and depression, as well as quantitative sensory tests (QST) such as conditioned pain modulation (CPM), temporal summation (TS), and pressure pain thresholds (PPTh). Here, we explored whether acute and chronic top surgery pain outcomes can be predicted by established psychological factors and QST.

Methods: Nineteen nonbinary and binary transmen consented to procedures approved by local ethics committees. Participants attended three visits: one week before (baseline), 1 week after (acute), and 6 months after surgery (follow-up). Primary patient reported outcome measures were pain severity and pain interference measured at each timepoint Bayesian correlations assessed associations between psychological measures (anxiety, pain catastrophizing, and depression) and pain outcomes at the acute and follow-up session; as well as QST measurements at baseline and follow up with these same pain outcome measures. Bayes Factor (BF) > 3 indicated meaningful evidence.

Results: Patients did not report clinically significant pain severity (>= 3/10) acutely (M = 1.95, SD = 1.21), or at follow-up (M = 1.82 , SD = 1.6). Baseline psychological predictors showed anecdotal evidence (BF10 < 3) for correlations with outcome measures. Acute pain severity was correlated with baseline CPM with strong evidence (BF10 = 25.01, Spearman’s rho = 0.66). At follow-up, baseline depression was correlated with pain interference with strong evidence (BF10 = 33.83, Spearman’s rho = 0.68). Baseline PPTh and TS showed anecdotal evidence for no correlation with pain outcome measures (BF10 = 1/3-1). Baseline CPM showed anecdotal evidence (BF10 = 1-3) for a correlation with pain outcome measures.

Conclusions: This study addresses a critical gap in understanding post-operative pain severity following gender-affirming top surgery. We found that baseline CPM—a reliable, and efficient way to characterize endogenous pain modulation—was strongly associated acute post-operative pain. Additionally, baseline depression correlated with long-term pain interference at follow-up. These findings suggest that pre-operative CPM testing may help identify patients at higher risk for more severe acute pain, while screening for depression could inform strategies to reduce long-term pain interference. Although preliminary given our sample size (n=19), this work identifies two potentially modifiable targets for improving pain outcomes in gender-affirming top surgery patients.

References: 1. Cooney, E. E. et al. Provision of gender-affirming care for trans and gender-diverse adults: a systematic review of health and quality of life outcomes, values and preferences, and costs. eClinicalMedicine 88, 103458 (2025).
2. Swan, J. et al. Mental health and quality of life outcomes of gender-affirming surgery: A systematic literature review. J. Gay Lesbian Ment. Health 27, 2–45 (2023).
3. Raner, G. A., Shapiro, J. S., Tse, T., Armstrong, K. & Potter, E. Binary and Nonbinary Transgender Patient Experiences Accessing Gender-affirming Top Surgery. Plast. Reconstr. Surg. - Glob. Open 12, e6198 (2024).
4. Anger, J. T. et al. Pain mechanisms in the transgender individual: a review. Front. Pain Res. 5, 1241015 (2024).
5. Kehlet, H., Jensen, T. S. & Woolf, C. J. Persistent postsurgical pain: risk factors and prevention. The Lancet 367, 1618–1625 (2006).
6. Weissman-Fogel, I., Sprecher, E. & Pud, D. Effects of catastrophizing on pain perception and pain modulation. Exp. Brain Res. 186, 79–85 (2008).
7. Katz, J. et al. Risk factors for acute pain and its persistence following breast cancer surgery. Pain 119, 16–25 (2005).
8. Tasmuth, T., Von Smitten, K. & Kalso, E. Pain and other symptoms during the first year after radical and conservative surgery for breast cancer. Br. J. Cancer 74, 2024–2031 (1996).
9. Schreiber, K. L. et al. Persistent pain in postmastectomy patients: Comparison of psychophysical, medical, surgical, and psychosocial characteristics between patients with and without pain. Pain 154, 660–668 (2013).
10. Edwards, R. R. et al. Alteration in Pain Modulation in Women With Persistent Pain After Lumpectomy: Influence of Catastrophizing. J. Pain Symptom Manage. 46, 30–42 (2013).
11. Fernández-Lao, C. et al. Widespread Mechanical Pain Hypersensitivity as a Sign of Central Sensitization after Breast Cancer Surgery: Comparison between Mastectomy and Lumpectomy. Pain Med. 12, 72–78 (2011).

Presenting Author: Batu Kaya
Submitting Author: Batu Kaya

Senior Author: Massieh Moayedi

IASP 2026 Global Year theme of Neuropathic Pain: No

• Emery Potter: NP-PHC - Women's College Hospital
• Kathleen Armstrong: MD, MSc FRCSC - Women's College Hospital