Twenty-five year results of the national cancer institute randomized breast conservation trial

Abstract

Breast conservation therapy (BCT) consisting of lumpectomy and postoperative radiation has become an accepted alternative to mastectomy (MRM) for the treatment of early stage breast cancer. We currently report the 25 year outcomes of a single institution, prospective, randomized clinical trial at the National Cancer Institute. 237 women with pathologically confirmed invasive breast tumors 5 cm or less were accrued between 1979 and 1987 and randomized to receive either BCT or MRM. Overall survival was the primary endpoint. Patients with node positive disease were included and treated with doxorubicin and cyclophosphamide. Both arms received axillary dissection. BCT patients had radiation to the whole breast followed by a boost. At a median follow-up of 25.7 years, overall survival was 43.8% for the MRM group and 37.9% for BCT (P = 0.38). Although the cumulative incidence of a disease-free survival event was higher in BCT patients (29.0% MRM vs. 56.4% BCT, P = 0.0017), the additional treatment failures were primarily isolated ipsilateral breast tumor recurrences (IBTR's) requiring salvage mastectomy. 22.3% of BCT patients experienced an IBTR. Distant disease and second cancers were similar in both arms. After 25 years, long term survival between BCT and MRM continues to be similar in patients treated for early stage breast cancer. Patients receiving BCT may be at risk for additional treatment-related morbidity, which may occur as a late event. Further studies are required to delineate patients at higher risk for these events, and prolonged follow up should be encouraged after treatment for all women.

Fig. 1

Study flow. MRM indicates modified radical mastectomy and BCT indicates breast conservation therapy

Fig. 2

Kaplan–Meier estimates of overall survival and cumulative incidence of disease-free survival between the MRM group compared with the BCT group. (MRM indicates modified radical mastectomy and BCT indicates breast conservation therapy)

Fig. 3

Risk of mortality and ipsilateral breast cancer by age for the BCT treatment group. Age was grouped into 10 years intervals, and Cox proportional hazards model was used to estimate the relative risk of death and ipsilateral breast tumor recurrence (IBTR) in each age group for patients in the BCT treatment group. The reference age group was (30, 40). The smoothed version of these relative hazards was performed by cubine spline interpolation