RISK FACTORS OF PAIN IN BREAST CANCER SURVIVORS: A SYSTEMATIC REVIEW AND META-ANALYSES

Leysen L.¹, Adriaenssens N.¹, Nijs J.¹, Pas R.¹, Bilterys T.¹, Vermeir S.¹, Beckwee D.¹

¹Vriije Universiteit Brussel, Physical Therapy, Brussels, Belgium

Background: Breast cancer remains the number one lethal malignancy in women. With the rising incidence numbers and decreased mortality rate due to the improved screening and treatments, the number of breast cancer survivors has increased. Consequently, sequelae and complications, such as pain, after breast cancer are becoming more important. The identification of risk factors for the development of pain in breast cancer survivors can be helpful for the improvement of prevention and treatment strategies.

Purpose: The aim of this review is to identify risk factors of pain in breast cancer survivors in a systematic, transparent and reproducible way with strict eligibility criteria and to conduct meta-analyses.

Methods: A systematic search of literature, based on the PRISMA guidelines, was conducted in databases PubMed and Web of Science to identify relevant publications during the period 1990 to 2015, regarding pain in cancer survivors. Studies were included if they provided the data to determine risk factors and if the subjects were cancer survivors, at least six months post-treatment (with exception of hormone therapy) and without recurrence or metastasis. Data were extracted by 3 authors using a self-created extraction form. Meta-analyses were carried out for the risk factors described in more than one article. Heterogeneity in effect estimates across studies was examined and a sensitivity analysis was performed in case of high heterogeneity.

Results: 12 studies were found eligible and over 40 factors were examined. A meta-analysis was performed for 13 factors. A significant difference for the chance of developing chronic pain was found for the following factors: age (overall OR: 0.61, 95% CI 0.44-0.86, p = 0.004), BMI (overall OR: 1.42, 95% CI 1.13-1.77, p = 0.002), education (overall OR: 1.27, 95% CI 1.10-1.47, p = 0.001), lymphedema (overall OR: 2.58, 95% CI 1.93-3.46, p 0.00001), axillary dissection (overall OR: 1.27, 95% CI 1.10-1.47, p = 0.001), chemotherapy (overall OR: 1.54, 95% CI 1.15-2.06, p = 0.004), hormone therapy (overall OR: 1.35, 95% CI 1.17-1.56, p 0.0001), and radiotherapy (overall OR: 1.39, 95% CI 1.12 - 1.72, p = 0.003). A sensitivity analysis was performed for the following factors: age, BMI, radiotherapy and mastectomy VS breast conserving surgery. Afterwards, age ( 50-55), BMI (> 30), and radiotherapy remained significant risk factors.

Conclusion(s): Age 50-55, BMI > 30, education 12-13 years, lymphedema, axillary dissection, chemotherapy, hormone therapy, and radiotherapy demonstrated to be significantly associated with an elevated chance for the development of chronic pain in breast cancer survivors, with lymphedema being the biggest risk factor.

Implications: Since an important portion of the cancer survivors face pain long after treatment ends, one should be aware of the possible risk factors for the development of this chronic pain in order to provide the best possible care and screening into survivorship.

Funding acknowledgements: This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.

Topic: Oncology, HIV & palliative care

Ethics approval: No ethics approval was needed to perform this systematic review.

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