The Relationship Between Sensory Loss and Persistent Pain 1 Year After Breast Cancer Surgery

Moderate to severe persistent pain after breast cancer surgery (PPBCS) affects 10 to 20% of the patients. Sensory dysfunction is often concomitantly present suggesting a neuropathic pain state. The relationship between various postoperative pain states and sensory dysfunction has been examined using quantitative sensory testing (QST), but only 2 smaller studies have examined PPBCS and sensory dysfunction in the surgical area. The purpose of this prospective study was to assess the relative importance of sensory function and PPBCS. QST consisted of sensory mapping, tactile detection threshold, mechanical pain threshold, and thermal thresholds. Two hundred ninety patients were enrolled and results showed that 38 (13%) had moderate to severe pain and 246 (85%) had hypoesthesia in the surgical area 1 year after surgery. Increased hypoesthesia areas were associated with pain at rest as well as during movement (P = .0001). Pain during movement was associated with a side-to-side difference of 140% (P = .001) for tactile detection threshold and 40% (P = .01) for mechanical pain threshold as well as increased thermal thresholds in the axilla (P > .001). Logistic regression models controlling for confounders showed larger areas of hypoesthesia as a significant risk factor, odds ratio 1.85 per 100 cm(2) for pain at rest and odds ratio 1.36 per 100 cm(2) for pain during movement. Perspective: PPBCS is associated with increasing areas of hypoesthesia as well as intraoperative nerve preservation. Thus, we hypothesize that PPBCS is associated with an interaction between a peripheral nociceptive drive in macroscopically preserved nerves and the central nervous system causing PPBCS as well as hypoesthesia. QST may identify patients suitable for intervention. (C) 2017 by the American Pain Society