By Jane Lewis
Younger age, radiotherapy, axillary lymph node dissection and greater acute postoperative pain are all associated with persistent pain after breast cancer surgery, reports a meta-analysis published online in the Canadian Medical Association Journal. Only axillary lymph node dissection provides a ‘high-yield target’ for a modifiable risk factor, the authors reported.
‘This study is a timely reminder to all those involved in treating patients with early breast cancer that persistent pain is both real and common,’ Professor Bruce Mann, Director of the Breast Tumour Stream, Victorian Comprehensive Cancer Centre, Melbourne, told Pain Management Today. ‘It is important that doctors reassure patients that this pain is rarely a sign that the cancer has returned, but a consequence of treatment, and then look for ways to manage the problem.’
The systematic review and meta-analysis, which included 30 observational studies (19,813 patients) reporting on 77 independent variables, found high-quality evidence for increased odds of persistent pain with younger age (odds ratio [OR] for every 10-year decrement, 1.36), radiotherapy (OR, 1.35), axillary lymph node dissection (OR, 2.41) and greater acute postoperative pain (OR for every 1 cm on a 10-cm visual analogue scale, 1.16). Moderate-quality evidence suggested an association with preoperative pain (OR, 1.29).
The strongest of the associations was with axillary lymph node dissection, which had an absolute increase in risk of persistent pain of 21%. Body mass index, type of breast surgery, chemotherapy and endocrine therapy were not associated with persistent pain.
According to Professor Mann, although more extensive treatment – axillary lymph node dissection as opposed to sentinel node biopsy, and adjuvant radiotherapy after breast conserving surgery – is associated with more pain, these ‘are important parts of breast cancer treatment, so usually this is something that must be accepted.’ However, tailoring the use of these treatments is the focus of current clinical trials.
‘The POSNOC trial, which is being run by the ANZ Breast Cancer Trials Group and is open at 10 centres around Australia and New Zealand, soon to be 20, is testing whether patients with limited disease in the sentinel node can safely be spared axillary node dissection,’ he said. ‘The current meta-analysis, which shows the strong association of axillary node dissection with persistent pain, highlights the importance of this trial.’
‘Trials are also open or opening to investigate whether selected patients with early breast cancer can be safely spared adjuvant radiotherapy,’ he added.
CMAJ 2016; doi: 10.1503/cmaj.151276.
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