[Intraoperative radiotherapy of locally advanced and recurrent rectal cancer]

Abstract

Intraoperative radiotherapy (IORT) offers a technique to increase radiation dose to the residual tumor or tumor bed while sparing neighboring radiosensitive organs. Beyond the mostly employed dedicated electron beam facilities, the afterloading--'flab'-technique was also used. In first prospective studies IORT was performed in patients with not completely resected locally advanced (T4) or recurrent tumors after complete external beam radiotherapy (50.4 Gy) as an additional boost dose, using small field sizes. This locally restricted dose escalation yielded higher local control and an increased prognosis. Nerves and ureters were dose limited. In our series IORT was performed for rectal carcinomas stages II and III. After an external beam radio- or radio-chemotherapy with 41.4 Gy, shrinking field boost irradiation was done intraoperatively with moderate doses and larger IORT field sizes. Compared to a historical control with high-dose external beam radiotherapy alone local control rate was increased. Radiogenic neuropathy or stenosis of the ureter was not observed. The impact on prognosis must awaited. Randomized studies are required to clearly describe the role of IORT in rectal carcinoma.