Can we identify patients with invasive breast cancer adequately treated with breast-conserving surgery alone?

The results of prospective randomized clinical trials demonstrated that the combination of conservative surgery and radiation therapy produced survival rates equivalent to those obtained with mastectomy for patients with Stage I and II invasive breast cancer. The identification, however, of a subset of patients who can be safely spared radiation therapy after breast-conserving surgery is an important goal. Randomized trials comparing conservative surgery alone with conservative surgery and radiation therapy consistently demonstrated a large reduction in the risk of local recurrence with the addition of radiation. Although no significant differences in survival were observed between these two groups, the available studies cannot exclude the possibility of a small survival advantage for patients treated with radiation therapy. Analyses of patient subsets within the randomized trials and within other prospective and retrospective studies failed to identify with consistence a subgroup of patients who did not benefit from radiation therapy. At present, radiation therapy should remain a part of breast-conserving treatment for patients with invasive breast cancer.