Identification of patient subgroups and risk factors for persistent arm/shoulder pain following breast cancer surgery

Abstract

Purpose

In this prospective, longitudinal study, we extend our findings on persistent breast pain in patients (n = 398) following breast cancer surgery and evaluate the prevalence and characteristics of persistent pain in the arm/shoulder. In addition, differences in the severity of common symptoms and quality of life outcomes measured prior to surgery, among the arm pain classes, were evaluated.

Methods and sample

Patients were recruited from Breast Care Centers located in a Comprehensive Cancer Center, two public hospitals, and four community practices. Patients were assessed prior to and monthly for six months following breast cancer surgery.

Results

Using growth mixture modeling, patients were classified into no (41.6%), mild (23.6%), and moderate (34.8%) arm pain classes based on ratings of worst arm/shoulder pain. Compared to the no pain class, patients in the moderate pain class were significantly younger, had a higher body mass index, and were more likely to report preoperative breast pain and swelling in the affected breast. In addition, patients in the moderate pain class reported higher levels of depression, anxiety, and sleep disturbance than the no pain class.

Conclusions

Findings suggest that approximately 35% of women experience persistent levels of moderate arm/shoulder pain in the first six months following breast cancer surgery. Moderate arm/shoulder pain is associated with clinically meaningful decrements in functional status and quality of life.

Introduction

Persistent pain following breast cancer surgery occurs in 25% to 60% of patients (Gartner et al., 2009). This pain problem is associated with mood disturbance, decrements in functional status, and decreases in quality of life (QOL) (Belfer et al., 2013, Stevens et al., 1995). However, in their recent review of persistent pain following breast cancer treatment, Andersen and Kehlet (2011) identified numerous limitations in the research studies done to date on this significant clinical problem. In addition to inconsistencies in the measurement of pain, only a limited number of studies have assessed for persistent pain in both the breast and shoulder/arm following breast cancer surgery.

In one of the earliest studies that compared occurrence rates based on anatomic site (Tasmuth et al., 1996), 10% of patients who underwent either mastectomy or breast conserving surgery reported pain in the ipsilateral arm. At one year, 39% of these patients reported persistent ipsilateral arm pain. Other studies have compared the prevalence of pain within the larger context of “arm and shoulder morbidities” in patients who had breast conserving surgery versus mastectomy (Carpenter et al., 1999, Nesvold et al., 2008, Vilholm et al., 2008); sentinel lymph node biopsy (SNLB) versus an axillary lymph node dissection (ALND) (Andersen et al., 2013, Brar et al., 2011, Haid et al., 2002, Langer et al., 2007, Ronka et al., 2005, Vilholm et al., 2008); and following receipt of radiation therapy (RT) (Deutsch and Flickinger, 2001, Hopwood et al., 2010, Vilholm et al., 2008). As noted by Andersen and Kehlet (2011), while the majority of studies reported no differences in arm pain between breast conserving surgery and mastectomy, these findings need to be interpreted with caution because the nociceptive effect of RT was not evaluated. In terms of SLNB versus ALND dissection, while inconsistent findings are noted in the literature, Andersen and Kehlet concluded that ALND is a risk factor for the development of persistent pain following breast cancer surgery.

Recently, our research group identified four subgroups of patients with distinct trajectories of persistent breast pain following breast cancer surgery (i.e., no (31.7%), mild (43.4%), moderate (13.3%), and severe (11.6%) pain) (Miaskowski et al., 2012). These subgroups differed on a number of demographic, preoperative, intraoperative, and postoperative characteristics. As part of our longitudinal study, separate assessments of arm/shoulder pain were done monthly for six months following surgery. These separate assessments of arm/shoulder versus breast pain were purposely designed to be comparable so that differences in persistent pain between the two distinct anatomic sites (e.g., different types of tissue at each site, different patterns of neural innervation) could be evaluated. Given that no studies were identified that evaluated for distinct subgroups and risk factors for persistent arm/shoulder pain following breast cancer surgery, the purposes of this prospective, longitudinal study, that recruited 398 women prior to surgery for breast cancer were to determine the prevalence of persistent pain in the arm/shoulder; characterize distinct persistent pain phenotype(s) 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 QOL outcomes measured prior to surgery, among the identified pain classes, were evaluated.