Persistent pain following breast cancer treatments remains a significant clinical problem despite improved treatment strategies. Data on factors associated with persistent pain are needed to develop prevention and treatment strategies and to improve the quality of life for breast cancer patients.
A prospective study has examined the prevalence and severity of and the factors associated with chronic pain after breast cancer surgery and adjuvant treatments.
Consecutive patients younger than 75 years with unilateral nonmetastasized breast cancer treated at the Helsinki University Central Hospital in 2006-2010 with either breast-conserving surgery or mastectomy with axillary surgery were eligible.
Patients receiving neoadjuvant treatment or immediate or delayed breast reconstruction or who had no breast cancer in the final histology were excluded.
Preoperatively, medical history, demographic data, Beck Depression Inventory, and Spielberger State-Trait Anxiety Inventory were obtained.
Preoperative pain in the operative area ( breast, axilla, arm ) during the previous week was assessed with a numerical rating scale of 0 to 10 ( 0 = no pain; 1-3 = mild; 4-6 = moderate; greater than or equal to 7 = severe ).
Perioperative analgesia was standardized. All patients received Acetaminophen ( Paracetamol ) and patient-controlled analgesia with intravenous Oxycodone.
Postoperatively, data were acquired on tumor and lymph node characteristics, complications of surgery, reoperations, and the prognostic risk category.
Adjuvant treatments were given according to international guidelines.
A questionnaire was sent to patients 12 months after surgery, with identical assessments of presence and intensity of pain.
Of 1536 eligible women, 387 were not recruited due to logistic reasons ( no research nurse available if operation started late ), 126 declined, and 23 were excluded after recruitment ( eg, because of change of type of operation ).
Thirty patients were later excluded because final histology indicated no cancer.
Of the remaining 970 patients, 860 ( 88.7% ) responded at 12 months to the questionnaire.
The mean age of the patients was 57.3 years; 24% had a chronic pain condition ( eg, fibromyalgia, low back pain ), the mean maximum pain intensity in the operative area was 1.3, 73% received radiotherapy, and 57% received chemotherapy.
At 12 months after surgery, 34.5% of the patients reported no pain, 49.7% mild pain, 12.1% moderate pain, and 3.7% severe pain.
The factors significantly associated with pain at 12 months were chronic preoperative pain, preoperative pain in the area to be operated, preoperative depression, axillary lymph node dissection, chemotherapy, and radiotherapy.
This prospective study found that 50% of patients had mild pain and 16% had moderate to severe pain 1 year after breast cancer surgery and identified factors associated with persistent pain.
Chronic preoperative pain, axillary lymph node dissection, radiotherapy, and adjuvant chemotherapy have been associated with persistent pain in previous, mainly retrospective studies, which have been inconclusive regarding the effect of preoperative psychological factors.
These findings may be useful in developing strategies for preventing persistent pain following breast cancer treatment. To identify patients who would benefit from preventive interventions, a risk assessment tool is needed. ( Xagena )
Meretoja TJ et al, JAMA 2014;311:90-92