The incidence, impact, and risk factors for moderate to severe persistent pain after breast cancer surgery: a prospective cohort study.

BACKGROUND: Few Australasian studies have evaluated persistent pain after breast cancer surgery. OBJECTIVE: To evaluate the incidence, impact, and risk factors of moderate to severe persistent pain after breast cancer surgery in a New Zealand cohort. DESIGN: Prospective cohort study. METHODS: Consented patients were reviewed at 3 timepoints (preoperative, 2 weeks and 6 months postoperative). Pain incidence and interference, psychological distress and upper limb disability were assessed perioperatively. Clinical, demographic, psychological, cancer treatment-related variables, quantitative sensory testing, and patient genotype (COMT, OPRM1, GCH1, ESR1, and KCNJ6) were assessed as risk factors using multiple logistic regression. RESULTS: Of the 173 patients recruited, 140 completed the 6-month follow-up. Overall, 15.0% (n = 21, 95% CI: 9.5%-22.0%) of patients reported moderate to severe persistent pain after breast cancer surgery with 42.9% (n = 9, 95% CI: 21.9%-66.0%) reporting likely neuropathic pain. Pain interference, upper limb dysfunction and psychological distress were significantly higher in patients with moderate to severe pain (P < .004). Moderate to severe preoperative pain (OR= 3.60, 95% CI: 1.13-11.44, P = .03), COMT rs6269 GA genotype (OR = 5.03, 95% CI: 1.49-17.04, P = .009) and psychological distress at postoperative day 14 (OR= 1.08, 95% CI: 1.02-1.16, P = .02) were identified as risk factors. Total intravenous anesthesia (OR= 0.31, 95% CI: 0.10 - 0.99, P = .048) was identified as protective. CONCLUSION: The incidence of moderate to severe persistent pain after breast cancer surgery is high with associated pain interference, physical disability, and psychological distress. Important modifiable risk factors were identified to reduce this important condition.

The Prevalence, Impact, and Risk Factors for Persistent Pain After Breast Cancer Surgery in a New Zealand Population.

OBJECTIVE: Few Australasian studies have assessed persistent pain after breast cancer surgery. This study aims to evaluate the prevalence, impact, and risk factors of moderate to severe persistent pain after breast cancer surgery in a New Zealand population. METHODS: Retrospective cross-sectional study of patients who underwent breast cancer surgery between six and 48 months previously. Validated questionnaires were used to assess pain prevalence and impact, psychological distress, and upper limb function. Patients' clinical records were assessed for potential risk factors. RESULTS: Of the 375 patients who were sent questionnaires, 201 were included in the study. More than half of the patients (N = 111, 55%) reported breast surgery related-persistent pain, with 46 (23%) rating the pain as moderate to severe. Neuropathic pain was reported by 21 (46%) patients with moderate to severe pain. Pain interference, upper limb dysfunction, and psychological distress were significantly higher in patients with moderate to severe pain (P < 0.001). Non-European ethnicity (odds ratio [OR] = 5.02, 95% confidence interval [CI] = 2.05-12.25, P < 0.001), reconstruction surgery (OR = 4.10, 95% CI = 1.30-13.00, P = 0.02), and axillary node dissection (OR = 4.33, 95% CI = 1.19-15.73, P < 0.03) were identified as risk factors for moderate to severe pain by multivariate logistic regression analysis. CONCLUSIONS: Moderate to severe persistent pain after breast cancer surgery affects many New Zealand patients, and is associated with impaired daily life activities, physical disability, and psychological distress. Large numbers of patients undergo breast cancer surgery annually. This study emphasizes the importance of identification and management of these patients perioperatively.