Iridium 192 plesiocurietherapy using silicone elastomer plates for extensive locally recurrent breast cancer following chest wall irradiation.

Abstract

From July 1985 to October 1988, 11 patients with prior treatment for breast cancer, and presenting an isolated superficial widespread inoperable chest wall recurrence, underwent plesiocurietherapy for salvage. Most patients (91%) had had a mastectomy. The recurrences developed in tissue that had previously been irradiated to 45-55 Gy in three patients and 65 Gy in eight patients. Salvage was attempted using two or three courses of plesiocurietherapy at monthly intervals to decrease treatment complications. The position of the active sources was maintained parallel but slightly shifted at each application. A total dose of 60 Gy was delivered to a Reference Isodose (R.I.) located 2 to 4 mm under the skin surface. The guide system consisted of plastic tubes inserted at 1.5 cm intervals into flexible silicone plates that were applied to the skin surface to maintain the actives lines 0.5 cm above the skin surface. The high dose sleeves surrounding the actives lines (dose greater than 2 x R.I.) were contained within the thickness of the silicone plate. The mean surface treated was 480 cm2 (range 30-1030 cm2). Two patients had continued progression of the lesions within the treated volume during and after curietherapy and died rapidly of metastatic disease. Nine (89%) patients showed complete regression of treated lesions. But two patients developed a new recurrence outside the treated volume. Complications were acceptable: five patients experienced regressive moderate to severe radiation dermatitis and one had skin necrosis that healed in 2 months. These preliminary results have shown that even when tumor extension and previous treatment theorically counter-indicate further local therapy for locally recurrent breast cancer, it is possible to obtain immediate and, at times, lasting control of local disease using two or three courses of plesiocurietherapy with a source shift.