INITIAL BRACHYTHERAPY IN THE BREAST-CONSERVATION APPROACH TO BREAST-CANCER

The outcome of 100 consecutive newly diagnosed breast cancer patients treated between 1975 and 1985 within a protocol of planned segmental m astectomy and radiation therapy that included an initial brachytherapy boost is reported. Margins were not routinely inked in this study and the tumor bed was determined with the operating surgeon at the time o f brachy therapy. There were 30 T1 tumors, 61 T2, and 9 T3. Segmental mastectomy was followed 2 weeks later by an interstitial implant with iridium-192 sources given as initial boost dose to the tumor bed, at t he time of axillary dissection. All patients received at least 20 Gy a s boost dose followed by external beam radiation to a total dose of 45 -50 Gy to the breast and regional nodes delivered over a period of 4-5 weeks. With a median follow-up of 7 years a total of 3 (3%) breast re currences were detected (1/30 in T1 tumors, 2/61 in T2 tumors). Only o ne of the three recurrences was at the initial tumor bed. None of the nine T3 patients included in this series recurred locally. There were 4 severe complications (2 soft tissue necroses and 2 osteonecroses) oc curring in 2/ 30 T1 and in 2/61 T2. Cosmetic results were good to exce llent in 77% of the cases and fair to poor in 23%. The actuarial local control and survival probability rate were, respectively, 95% and 85% at 5 years and 93% and 73% at 10 years. Initial brachytherapy boost t o a target volume accurately determined with the operating surgeon fol lowed by subsequent external beam radiotherapy achieved excellent loca l control in the breast even for lesions larger than 2 cm (70% of the reported cases).