Pathological tissue changes following intraoperative radiotherapy.

Ninety patients with a variety of advanced-stage malignancies were treated with surgical resection, when feasible, and with intraoperative radiotherapy. Certain patients received additional external beam radiotherapy. During clinical follow-up, 45 patients died. Twenty-two patients (49% of deaths) underwent detailed autopsies between 1 and 18 months after treatment, with special attention directed towards assessing radiation damage to various tissues. Histological changes related to radiation were generally manifested as fibrosis. Mild fibrotic changes in retroperitoneal soft tissues and mild hypocellularity in vertebral bone marrow were consistently present in patients treated for pancreatic carcinoma, gastric carcinoma, and retroperitoneal or pelvic sarcomas. Fibrosis of the soft tissues of the porta hepatis without narrowing of the bile duct was present in patients treated for pancreatic or gastric cancer. perineural fibrosis was present in retroperitoneal and pelvic nerve trunks in patients treated for abdominal or pelvic sarcomas and in patients treated for unresectable carcinoma of the pancreas. Significant radiation-related changes were generally not observed in major blood vessels, intestine, or ureter. Intact irradiated primary tumors consistently displayed necrosis.