Post mastectomy radiotherapy (PMRT) improves both locoregional control and overall survival in patients with locally advanced breast cancer. This has been demonstrated in both pre and postmenopausal women.
The evidence supporting this protocol is provided by a meta-analysis of 8135 women with early breast cancer enrolled in 22 trials of post-mastectomy chest wall and regional nodal irradiation.r There were 1314 women with 1-3 positive axillary nodes in the analysis. PMRT reduced the locoregional recurrence rate (2p<0.00001), overall recurrence rate (RR 0.68, 2p<0.00006), breast cancer mortality (RR 0.80, 2p = 0.01). Of those 1314 women, 1133 also had systemic therapy with CMF chemotherapy or Tamoxifen.
There were 1772 women with 4 or more nodes positive in the analysis. PMRT reduced the locoregional recurrence rate (2p=0.00001), overall recurrence rate (RR 0.79, 2P= 0.0003), breast cancer mortality (R=0.87, 2p=0.04). Any death 20 year gain=7.6% (RR=0.89, 2p=0.05). Median follow up time for the group was 9.4 years. For every 1.5 recurrences (either locoregional or distant) prevented during the first 10 years, 1 breast cancer death was prevented at 20 years.
ER (oestrogen receptor), PR (progesterone receptor) and HER2 (human epidermal growth factor receptor 2) “Triple negative” receptor breast cancer patients
For women with triple-negative early stage breast cancer, the use of adjuvant radiation therapy has been found to be favourable.rr
Wang et alr randomised 681 patients with triple negative, stage I-II breast cancer after mastectomy to receive adjuvant chemotherapy +/- adjuvant radiotherapy. After a median follow up of 86.5 months, five-year recurrence free survival rates were 88.3% for adjuvant chemotherapy plus radiation and 74.6% for adjuvant chemotherapy alone with a significant difference between the two groups (HR 0.77 [95% CI 0.72, 0.98]; P = 0.02). Five year overall survival significantly improved in adjuvant chemotherapy plus radiation group compared with chemotherapy alone (90.4% and 78.7%) (HR 0.79 [95% CI 0.74, 0.97]; P = 0.03) with no significant toxicity reported.
Fig 3. Effect of radiotherapy (RT) after mastectomy and axillary dissection (Mast+AD) on 10-year risks of locoregional and overall recurrence and on 20-year risk of breast cancer mortality in 1314 women with one to three pathologically positive nodes (pN1–3) and in 1772 women with four or more pathologically positive nodes (pN4+).