PMPS: A Common Late Effect of Surgery and Radiation for Breast Cancer
Postmastectomy pain syndrome is a debilitating late effect of surgery and radiation therapy for breast cancer.
Breast cancer surgery and adjuvant radiotherapy can damage nerves and cause postmastectomy pain syndrome (PMPS), with important implications for patients' quality of life and survivorship care. Oncology nurses play a crucial role in spotting patients at high risk for PMPS, educating them about symptoms, and monitoring (and documenting the need for monitoring) for PMPS during recovery and survivorship.
Postmastectomy pain syndrome is a chronic, potentially progressive, and debilitating neuropathic sequela of breast cancer treatment that persists beyond 3 months.1,2
Affecting up to half of women who undergo breast cancer surgery, postmastectomy pain syndrome typically involves aching, tingling, itching, electric shock-like, or burning pain in the chest wall, underarm (armpit, or upper arm).1-3 Some patients have only one such symptom, but others experience combinations of these painful sensations; one woman described the intense throbbing and itching she felt as “poison ivy lit by a blowtorch.”4
Shoulder movement sometimes causes acute exacerbations of symptoms. PMPS symptoms can persist for many years, and pain intensity can vary over time.
Postmastectomy pain syndrome can have profound impacts on cancer survivors' quality of life, social and sexual functioning, and ability to work. Sleep disturbance and anxiety are common among women with PMPS and may affect pain severity.1,3,5 Yet PMPS is not always discussed with patients before they undergo surgery and adjuvant radiotherapy.4
Despite its name, postmastectomy pain syndrome also has been reported by women who underwent breast-conserving surgery (BCS), and the adverse effect is no more common following mastectomy than BCS.3 Perhaps surprisingly, postsurgical complications such as lymphedema or cellulitis do not appear to predict postmastectomy pain syndrome, despite shared risk factors such as axillary lymphadenectomy.6 With declining rates of full axillary lymphadenectomy, PMPS incidence may be declining.1
Postmastectomy pain syndrome is believed to arise from tissue and nerve damage associated with resection. Resection of tissue in the breast's upper outer quadrant or axillary lymph nodes appears to increase the risk of symptoms.1,3,7
Women undergoing breast cancer surgery routinely receive adjuvant regional radiotherapy to kill residual tumor cells and micrometastases. Several studies have found that adjuvant radiotherapy following mastectomy or BCS is associated with a higher risk for PMPS than surgery without radiotherapy.3,8,9 A 2009 study of PMPS found that the odds ratio (OR) for adjuvant radiotherapy was 1.5 (95% CI, 1.08-2.07; P =.03), meaning that women who underwent adjuvant radiotherapy faced a 50% higher risk for PMPS compared with women who underwent breast cancer surgery without radiotherapy.3
Other risk factors have also been identified. Chief among these is patient age (eg, younger than 35 years at diagnosis).7,10 Younger women are more likely to experience PMPS, but whether this is related to different psychosocial stressors and anxiety or age-related nerve tissue responses to surgery and radiotherapy is not clear.1,3
Some studies suggest that presurgical breast pain and acute pain immediately following breast surgery might increase the risk for PMPS.3 A prior history of headache is also predictive of PMPS.7 Frequent headache has been linked to central sensitization — hypersensitivity that, over time, leaves a person prone to chronic pain.7 Frequent headache is a risk factor for other regional pain syndromes, in addition to PMPS.7 The neurologic processes involved in PMPS are poorly understood and likely involve aberrations in the peripheral nervous system that, over time, contribute to central nervous system problems.11