Caesium(137) implant as sole radiation therapy for operable breast cancer: a phase II trial

Clinical trials have indicated the need for irradiation of the tumour-bearing quadrant in patients with operable breast cancer treated by conservation therapy even under circumstances where there has been complete pathologic clearance. The aim of this phase II trial was to replace whole breast irradiation with brachytherapy to the tumour bed.

A series of 50 patients with operable breast cancers measuring <==4 cm diameter were treated by combination therapy comprising tumour excision axillary clearance and synoperative insertion of a rigid implant to the tumour bed. The implant was after-loaded with medium dose rate Cs(137) sources giving a dose of 45 Gy in daily four fractions of about 6 h duration. No external beam radiotherapy was given.

After a median follow-up of 6.3 years, of the 49 evaluable patients, 80% were alive without relapse. Of the 9 patients (18%) who developed a breast relapse, the site of recurrence was in the index quadrant in 7 cases (78%). Of the series, 26 (81%) gave a subjective rating of cosmetic outcome which was excellent or good. Objectively the treated breast was deemed to be normal in 11 (42%) and abnormal in 15 (58%).

This phase II study suggests that in a selected group of patients with early breast cancer, external whole breast radiotherapy can be replaced by interstitial irradiation to the tumour bed without compromising local disease control and giving an excellent or good cosmetic outcome in the majority of cases.