"A critical weekly review of important new research findings for health-conscious readers..."
By, Robert A. Wascher, MD, FACS
The information in this column is intended for informational purposes only, and does not constitute medical advice or recommendations by the author. Please consult with your physician before making any lifestyle or medication changes, or if you have any other concerns regarding your health.
BREAST CANCER TREATMENT & CHRONIC PAIN
Chronic pain following breast cancer treatment is, unfortunately, relatively common, and is a subject that I have previously extensively studied and written about. Most of the clinical data that has been published, thus far, about chronic pain following breast cancer therapy is from the “mastectomy era,” when every patient with breast cancer routinely underwent complete dissection (removal) of the breast and armpit lymph nodes (also known as modified radical mastectomy).
Chronic pain following breast cancer treatment has been estimated to occur, on average, in approximately 25 to 30 percent of patients undergoing axillary (armpit) lymph node dissection, with or without mastectomy, and appears to correlate with the extent of axillary lymph node surgery. Important additional non-surgery factors that have been linked to breast cancer treatment-associated chronic pain syndromes include neuropathic pain caused by chemotherapy and radiation therapy, both of which may be additive to the neurological impairments associated with surgery. As occurs with many other types of chronic pain syndromes, affected breast cancer patients frequently experience some degree of disability that interferes with their ability to lead productive and comfortable lives. Moreover, the added overlay of the emotional stress and anxiety that commonly follows the diagnosis of breast cancer further adds to the impact of chronic pain on the daily lives of patients who have undergone breast cancer treatment.
A newly published public health study of chronic pain following breast cancer treatment appears in this week’s Journal of the American Medical Association. In this large Danish epidemiological study, a nationwide cohort of 3,253 breast cancer survivors, ages 18 to 70 years, was extensively surveyed regarding their breast cancer treatment history and outcomes two to three years following completion of their breast cancer treatment. (It is important to note that all of the women who participated in this study underwent current standard-of-care breast cancer surgery in 2005 or 2006.) The results of this large nationwide Danish breast cancer study were very instructive.
Among these more than 3,000 patients, nearly half (47 percent) reported ongoing pain issues two to three years after completing their breast cancer therapy. Among these 1,543 patients with chronic pain symptoms, 13 percent reported severe pain (or, about 6 percent of all patients participating in this study). Another 39 percent of these 1,543 patients reported moderate pain (18 percent of all study patients). Finally, 48 percent of these 1,543 patients reported mild chronic pain symptoms (23 percent of all study patients). Among this group of patients with chronic pain following completion of breast cancer therapy, 20 percent were sufficiently bothered by their symptoms to seek out medical evaluation and treatment.
Following statistical analysis of the data, several important clinical factors were found to be significantly associated with chronic pain following breast cancer treatment, some of which have also been confirmed by previous studies. Young age was a particularly important risk factor for chronic pain following breast cancer treatment. Patients between the ages of 18 and 39 in this study were almost four times more likely to report chronic post-treatment pain than older women. Radiation therapy was also a significant risk factor (nearly all women who undergo breast-conserving “lumpectomy” will be advised to undergo radiation therapy to reduce the risk of local recurrence of their breast cancer). Women who underwent radiation therapy following breast cancer surgery were almost twice as likely to report chronic pain when compared to the women who did not receive radiation treatment. (Chemotherapy, on the other hand, did not appear to be associated with chronic pain in this large group of breast cancer survivors.) The extent of axillary lymph node surgery was also a predictive factor for chronic pain, as has been shown by previous research (including my own research). Women who had undergone complete removal of their axillary lymph nodes were nearly twice as likely to report chronic pain when compared to patients who had undergone the more limited sentinel lymph node biopsy of their axillary lymph nodes.
A separate risk factor for chronic pain following breast cancer treatment was the presence of chronic pain in other areas of the body prior to undergoing breast cancer treatment, suggesting that women who have preexisting chronic pain symptoms are more likely to develop a new chronic pain syndrome following breast cancer treatment.
In addition to chronic pain, decreased or abnormal sensation of the skin of the chest wall, axilla, and upper arm are well known side effects of breast cancer treatment. In this study, abnormal sensation was also more common among younger patients (5 times more likely than for older women), and following complete axillary lymph node dissection (5 times more likely than for women who did not undergo complete axillary lymph node dissection).
This study adds to an important and growing body of clinical research regarding the prolonged effects modern breast cancer therapy on patients. When contrasted to the rather high incidence of chronic pain syndromes associated with modified radical mastectomy, the recent data on chronic pain and sensory abnormalities in the “modern era” of breast-conserving surgery is much more favorable, although, clearly, there is still a substantial proportion of women who will go on to experience significant long-term symptoms following completion of their breast-conserving treatment.
The links below provide additional information for patients who are interested in this important topic: