[Peroperative irradiation: the Massachusetts General Hospital technic and current experience]

Intra-operative radiotherapy (IORT) is a technique developed since the early 60s mainly in Japan and in the U.S.A. It usually consists of a single fraction of electrons given intra-operatively. Doses range from 10 to 35 Gy and may be combined with external beam irradiation. The salient advantages are: 1) a better target volume definition with the surgeon; 2) the possibility of removing normal structures (such as the small bowel) from the beam and of so delivering a much higher tumor dose. The disadvantages are: 1) theoretically, a lesser effect on hypoxic cells compared with a fractionated regimen; 2) a requirement for perfect cooperation between surgeon and radiotherapist; 3) a cumbersome apparatus. From pilot studies conducted so far, it appears that advanced poorly or unresectable rectal carcinomas, retroperitoneal soft tissue sarcomas and gastric carcinomas may benefit from such an approach while resected or unresectable pancreatic carcinomas, in spite of extensive evaluation, do not. The management of prostatic, bladder, cerebral, intrathoracic and gynecologic malignancies with IORT is undergoing active prospective studies in some 60 Japanese, American (and, in 1986, 7 French) centers. The major technical issues and drawbacks of this technique will also be discussed.