Breast conservation therapy for early stage breast carcinoma with outstanding 10-year locoregional control rates: a case for aggressive therapy to the tumor bearing quadrant.

Abstract

Between 1982 and 1988 233 American Joint Committee on Cancer Stage I and II invasive breast carcinomas were prospectively treated in 225 women with conservative tumor excision, careful assessment of histopathological margins, and dose-adjusted irradiation to maximum doses of 70 Gy to the tumor bearing quadrant of the breast. The pathological stages at presentation were T1N0 and T1N1 in 57% and 13% and T2N0 and T2N1 in 19% and 10% of the patients, respectively. All patients were irradiated according to a policy that, beyond the 50 Gy to the whole breast and draining lymphatics, the tumor-bearing quadrant was boosted in adjustment to the histopathological margin. Normal tissue margins of < 2 mm were considered positive, margins 2-5 mm close, and margins > 5 mm negative and were boosted with 20, 15, and 10 Gy, respectively. Patients in whom the margin could not be assessed were re-excised or boosted to 20 Gy. Re-excisions with no residual carcinoma were not boosted. Most patients boosted to 20 Gy to the tumor-bearing quadrant received interstitial 192-Ir implantations. The actuarial local control rates in the treated breast were 97.5% at 10 years with three recurrences having occurred at a median of 4.5 years after completion of radiotherapy. An additional two patients failed regionally outside the irradiation portals. The overall and disease-free survival of the whole group is 87.5% and 77%, respectively. The approach to breast conservation therapy followed in this study has resulted in outstanding local control rates and suggests that there may be a subset of patients that could be irradiated to the tumor bearing quadrant only.