High dose, external beam and intraoperative radiotherapy in the treatment of resectable and unresectable pancreatic cancer.

Ninety patients with pancreatic cancer were treated by external beam radiotherapy (EBRT) and/or intraoperative radiotherapy (IORT) with or without surgical resection of the tumor, and the results were compared with those of a historical control comprising 112 patients treated by surgery alone. At an early stage of this study, postoperative EBRT (50-60 Gy) or IORT (25-33 Gy) was given alone, but recently the two modalities have been combined. The combination of high doses of EBRT and IORT was well tolerated provided that the gastrointestinal tract was not irradiated during IORT. Although EBRT plus IORT appeared to yield better results than either EBRT or IORT alone, the difference was not significant on multivariate analysis, and patients receiving EBRT, IORT, or EBRT + IORT were grouped together. Patients receiving radiotherapy in addition to macroscopically curative surgery had a slightly longer median survival time (14 months) than those receiving curative surgery alone (10 months), but the 3-year survival rate was similar (21% vs. 19%). In patients who underwent noncurative resection, the median survival time was significantly longer for the irradiated group (12 months) than for the control group (6.5 months). Also, in patients with unresectable lesions but no distant metastases, irradiation prolonged the median survival time significantly (8 vs. 3.5 months). In this group, there was one 5-year survivor, who received EBRT of 55 Gy plus IORT of 30 Gy to his unresectable pancreatic body lesion. Patients with metastases were also treated for palliation of symptoms, but it was found that irradiation prolonged the median survival time even in such cases (4.5 vs. 2.5 months). Based on these results, we plan to use EBRT plus IORT in all pancreatic cancer patients with no metastases.