A preliminary report of intraoperative radiotherapy (IORT) in limited-stage breast cancers that are conservatively treated

Local recurrences after breast conserving surgery occur mostly in the quadr ant harbouring the primary carcinoma. The main objective of postoperative r adiotherapy should be the sterilisation of residual cancer cells in the ope rative area, while irradiation of the whole breast may be avoided. We have developed a new technique of intra-operative radiotherapy (TORT) of a breas t quadrant after the removal of the primary carcinoma. A mobile linear acce lerator (linac) with a robotic arm is utilised delivering electron beams ab le to produce energies from 3 to 9 MeV. Through a perspex applicator, the r adiation is delivered directly to the mammary gland and to spare the skin f rom the radiation, the skin margins are stretched out of the radiation fiel d. To protect the thoracic wall, an aluminium-lead disc is placed between t he gland and the pectoralis muscle. Different dose levels were tested from 10 to 21 Gy without important side-effects. We estimated that a single frac tion of 21 Gy is equivalent to 60 Gy delivered in 30 fractions at 2 GY/frac tion. Seventeen patients received a dose of TORT of 10 to 15 Gy as an antic ipated boost to external radiotherapy, while 86 patients received a dose of 17-19-21 Gy intra-operatively as their whole treatment. The follow-up time Of the 101 patients varied from 1 to 17 months (mean follow-up time was 8 months). The IORT treatment was very well accepted by all of our patients, either due to the rapidity of the radiation course in cases where TORT was given as the whole treatment or to the shortening of the subsequent externa l radiotherapy in cases where TORT was given as an anticipated boost. We be lieve that single dose TORT after breast resection for small mammary carcin omas may be an excellent alternative to the traditional postoperative radio therapy. However, a longer follow-up is needed for a better evaluation of t he possible late side-effects. (C) 2001 Published by Elsevier Science Ltd. All rights reserved.