Background: Risk factors associated with persistent pain after breast cancer treatment are needed to develop prevention and treatment strategies to improve the quality of life for patients with breast cancer.
Objectives: To identify factors associated with persistent pain in women undergoing breast cancer treatments.
Study design: Retrospective study.
Setting: Regional hospital in the Netherlands.
Methods: The primary outcome was pain associated with surgery at more than 6 months postoperatively and patients were stratified based on the associated visual analog" scale score they reported: reporting no pain as "no pain," pain 1 - 29 mm as "mild pain," and pain 30 - 100 mm as "moderate/severe pain." Secondary outcomes were function, symptom, and total quality of life scores. Predefined risk factors analyzed for association with outcomes included: age, smoking status, diabetes, body mass index (BMI), disease stage, surgery type, axillary lymph node dissection, reoperation, chemotherapy, radiotherapy, and hormone therapy.
Results: Of the 718 patients who were approached, 492 were included (follow-up 2.5 ± 1.8 years). Thirty-five percent of patients developed persistent pain (n = 122 "mild pain," n = 53 "moderate/severe pain'"). Age, BMI, surgery type, axillary lymph node dissection, disease stage, reoperation, chemotherapy, and radiotherapy were identified as potential risk factors in univariate ordinal regression analyses (P < 0.10). Age (P < 0.01) and BMI (P = 0.04) remained independently predictive in the multivariate model. BMI and age were associated with odds ratios (ORs) of 1.04 (95% confidence intervals (CI): 1.00 - 1.08) and 0.97 (95% CI: 0.95 - 0.99), respectively per point and year increase. BMI was associated with a higher symptom score (r = 0.14, P < 0.01), a lower level of function (r = -0.11, P = 0.01), and lower total quality of life scores (r = -0.13, P < 0.01).
Limitations: The retrospective nature of this study makes it prone to response and misclassification bias.
Conclusions: BMI and age may be risk factors for persistent postoperative pain after breast cancer treatment.
Key words: Persistent postsurgical pain, breast cancer treatment, BMI, age, chronic postoperative pain, breast cancer surgery.