INTRAOPERATIVE RADIOTHERAPY OF RECTAL-CAR CINOMA

Intraoperative radiotherapy (IORT) offers a technique to increase radi ation dose to the residual tumor or tumor bed while sparing neighborin g 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 com pletely resected locally advanced (T4) or recurrent tumors after compl ete external beam radiotherapy (50.4 Gy) as an additional boost dose, using small field sizes. This locally restricted dose escalation yield ed higher local control and an increased prognosis. Nerves and ureters were dose limited. In our series IORT was performed for rectal carcin omas stages' II and III. After an external beam radio- or radio-chemot herapy with 41.4 Gy, shrinking field boost irradiation was done intrao peratively with moderate doses and larger IORT field sizes. Compared t o a historical control with high-dose external beam radiotherapy alone local control rate was increased. Radiogenic neuropathy or stenosis o f the ureter was not observed. The impact on prognosis must awaited. R andomized studies are required to clearly describe the role of IORT in rectal carcinoma.