Role of radiotherapy following total mastectomy in patients with early breast cancer. The Closed Trials Working Party of the CRC Breast Cancer Trials Group.

Between June 1970 and April 1975 the CRC (King's/Cambridge) Trial for early breast cancer randomized 2800 patients following mastectomy to immediate prophylactic radiotherapy (DXT group, n = 1376) or control (WP group, n = 1424). Although no difference in overall survival has been demonstrated, there is an increase in mortality in the irradiated patients from nonbreast cancer causes beyond 5 years. It is because of an increase in the number of deaths due to new nonbreast malignancies [RR V 1.89 (1.18-3.05)] and to cardiac-related disease [RR = 1.52 (1.01-2.29)]. This increased cardiac death rate may be related to the use of orthovoltage, which has greater scatter. There was a significant increase in risk for those with left-sided rather than right-sided tumors in this subgroup [chi 2 (int) = 5.08; p = 0.02]. Local relapse was significantly reduced in those patients randomized to radiotherapy [RR = 0.44 (0.39-0.51)]. Median survival following local relapse was 1.35 years in the DXT group and 2.66 years in the WP group (logrank p < 0.001). Patients with the first relapse in the supraclavicular nodes had a particularly poor prognosis (median survival: DXT 0.69 years; WP 1.37 years). Almost 50% of patients who have had a recurrence on the chest wall or in the axilla and subsequently died have had disease at the same site at death, regardless of whether they had radiotherapy immediately following surgery. However, the actual number of patients dying with persistent disease is halved by the use of prophylactic radiotherapy (DXT 66; WP 143). Classic pathological features such as tumor size, tumor grade, and nodal involvement help define those patients at high risk of local failure who should be recommended for immediate radiotherapy.

RCT Entities:   Population Interventions Outcomes