A new study has reported that breast conserving treatment is not associated with increased likelihood of locoregional recurrence (recurrence in the breast, chest wall, or lymph nodes) compared to mastectomy in triple negative breast cancer patients. Triple negative disease is a subtype of breast cancer that is estrogen receptor negative (ER-), progesterone receptor negative (PR-), and human epidermal growth factor receptor 2 negative (HER2-).

The study was designed to investigate whether women with triple negative breast cancer who undergo breast conserving treatment (typically, radiotherapy) are more likely to develop a locoregional recurrence than triple negative patients who undergo mastectomy. Triple negative disease is an aggressive breast cancer subtype known to have a relatively high risk of locoregional recurrence. The study included 1,325 women with triple negative breast cancer who underwent either breast conserving therapy or mastectomy at the M.D. Anderson Cancer Center in Houston, Texas between 1980 and 2010. A total of 651 (49%) of the women received breast conserving treatment and the other 674 (51%) had mastectomies. The women were followed for a median of 62 months.

The women who underwent mastectomy had larger tumors, a higher incidence of lymphovascular invasion (invasion of the cancer cells into the blood vessels or lymphatic channels), and greater lymph node involvement than the women who received breast conserving treatment. In other words, women in the mastectomy group had worse prognostic indicators (however, the authors took this into account when performing the lumpectomy vs. mastectomy comparison). Locoregional recurrence occurred less frequently in the breast conserving group during follow up (170 (26%) of the breast conserving group compared to 203 (30%) of the mastectomy group). Five-year locoregional recurrence-free survival rates were also higher in the breast conserving group (76% compared to 71%), as was distant metastasis-free survival (68% compared to 54%) and overall survival (74% compared to 63%). Higher tumor stage, higher tumor grade, the presence of lymphovascular invasion, close or positive surgical margins, and use of non-anthracycline/taxane-based adjuvant chemotherapy each increased the risk of locoregional recurrence. On the other hand, age over 50 years was associated with lower risk. Type of surgery was not found to be associated with risk of locoregional recurrence. The authors conclude that triple negative breast cancer should not be considered a contraindication for breast conservation.

Please see our article on the latest research concerning triple negative prognosis for more information.