Improvement of survival with postmastectomy radiotherapy in patients with 1-3 positive axillary lymph nodes: A systematic review and meta-analysis of the current literature

In breast cancer with >4 positive axillary lymph nodes, it is common practice to deliver radiotherapy to the affected site following mastectomy. However, less is known regarding the benefits this may confer on women with 1-3 positive lymph nodes. In this meta-analysis, we aimed to assess whether post-mastectomy radiotherapy (PMRT) was beneficial for such patients. A literature review was conducted using the PubMed and Ovid databases. Selected studies were analysed and data regarding overall survival (OS) and locoregional recurrence (LRR) rates were extracted. Statistical analysis was then conducted in order to develop a combined risk ratio (RR) for both OS and LRR in the setting of PMRT in women with breast cancer with 1-3 positive lymph nodes. PMRT in women with 1-3 positive lymph nodes significantly reduced the risk of LRR, with a RR of 0.3 [95% confidence interval (CI): 0.23-0.38] and also showed a minor benefit in terms of OS (RR=1.03, 95% CI: 1.00-1.07). Therefore, in breast cancer patients with 1-3 positive lymph nodes, PMRT significantly reduced the risk of LRR and was associated with a minor OS benefit. Until the results of ongoing randomised controlled trials are published, PMRT should be recommended in this group of patients following a careful multidisciplinary discussion.