Is Radiotherapy Unnecessary for Some Breast Cancer Patients?

The ability of radiotherapy (RT) to lower risk for local breast cancer recurrence (LR) after breast-conserving surgery is indisputable. But for some subgroups, the benefit could be so small that RT might be avoided. For example, prior reports have suggested that patients with luminal A molecular subtype tumors — defined as estrogen receptor (ER)-positive, progesterone receptor (PR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, low proliferative rate, and low-to-intermediate nuclear grade — may have such a low baseline risk for LR that RT is unnecessary.

To examine this issue further, investigators conducted a reanalysis of the Toronto–British Columbia (TBC) trial (N Engl J Med 2004; 351:963) involving 769 women aged ≥50…