Radiotherapy Benefit Confirmed in Patients Undergoing Breast Conservation

William J. Gradishar, MD

Long-term follow-up data show that recurrence was less common after adjuvant radiotherapy, primarily during the first 5 years.

The standard of care for patients with early-stage breast cancer undergoing breast conservation surgery is to receive postoperative radiotherapy (XRT), a standard established after the findings of multiple randomized clinical trials. The Uppsala/Orebro study with 10 years of follow-up (J Clin Oncol 1999; 17:2326) was one of the first randomized clinical trials to demonstrate the benefit of adjuvant XRT to the breast. Now, investigators report results of the trial after 20 years of follow-up.

A total of 381 women with stage 1 (pT1N0) breast cancer were randomized to sector resection — which is more extensive than standard lumpectomy but less so than quadrantectomy — with XRT (54 Gy in 27 fractions) or without XRT.

Results were as follows:

• The cumulative probability of a first breast cancer event was 30.9% with XRT and 45.1% without XRT (hazard ratio, 0.58); this benefit of XRT was achieved within the first 5 years.
• Overall mortality was 50.4% with XRT and 54.0% without XRT (HR, 0.09).
• The cumulative probability of contralateral cancer or death from cancer other than breast cancer was 27.1% with XRT and 24.9% without XRT (HR, 1.17).
• In low-risk women (older than 55 without comedo-type or lobular carcinomas), the cumulative incidence of first breast cancer of any type was 24.8% with XRT and 36.1% without XRT (HR, 0.61).

Citation(s):

Wickberg A et al. Sector resection with or without postoperative radiotherapy for stage I breast cancer: 20-year results of a randomized trial. J Clin Oncol 2014 Feb 3; [e-pub ahead of print].