Identification of distinct subgroups of patients with arm pain following breast cancer surgery

Pain at the site of injury is a common symptom in women who undergo breast cancer surgery. Pain often involves the axilla and arm ipsilateral to the affected breast. Persistent post-surgical pain in the arm is estimated to occur in 20% to25% of patients following breast cancer surgery. However, detailed phenotypic characterization of persistent arm pain is lacking. The study purposes were to determine the prevalence of persistent pain in the arm; characterize distinct persistent pain classes using growth mixture modeling (GMM), and evaluate for differences among these pain classes in demographic, preoperative, intraoperative, and postoperative characteristics. In addition, differences in the severity of common symptoms and quality of life outcomes measured prior to surgery, were evaluated among the pain classes. Patients (n=398) were recruited prior to surgery and followed monthly for six months. Based on 0 to 10 ratings of worst pain, patients were classified into “No” (41.6%), “Mild” (23.6%), and “Severe” (34.8%) pain groups using GMM. Differences were identified in a number of demographic (i.e., age, ethnicity, body mass index, functional status, number of comorbidities), preoperative (i.e., number of breast biopsies, neoadjuvant chemotherapy, stage of disease, breast pain), intraoperative (i.e., number of lymph nodes removed, type of surgery, axillary lymph node dissection, intercostobrachial nerve sacrificed), and postoperative (number of postoperative complications, severity of average and worst postoperative pain, placement of a surgical drain, received biological therapy or physical therapy during the 6 months) characteristics among the pain classes (all p<.05). In addition, patients in the Severe Pain class reported higher preoperative levels of depression (p<0.05), fatigue (p<0.001), sleep disturbance (p<0.001) and quality of life (p<0.001) than the No Pain class. Findings suggest that approximately 35% of women experience significant and persistent levels of breast pain in the first six months following breast cancer surgery.