Intraoperative radiotherapy and hyperthermia for unresectable pancreatic cancer.

Intraoperative radiotherapy (IORT) is a safe and efficient method of delivering a high single dose of radiation to a target. IORT has a significant effect on abdominal pain and back pain in patients with unresectable pancreatic cancer, but IORT alone is not so effective in improving the prognosis. The combination of IORT with external beam radiotherapy (EBRT) can achieve a higher local control rate than EBRT alone, although most previous studies have not necessarily indicated any improvement in survival. We recently found that high-dose IORT (30 Gy) + EBRT (40-60 Gy) was more effective than EBRT alone in patients with a CA 19-9 level < 1000 U/ml. Thus, IORT plus EBRT can be recommended for unresectable but localized pancreatic cancer associated with low tumor marker levels. Hyperthermia combined with radiation or chemotherapy is another possible treatment strategy, but no effective method of delivering external regional hyperthermia has yet been established. Thermometry is another problem with external hyperthermia. At present, intraoperative hyperthermia given in combination with IORT seems to be the best method of heating a pancreatic tumor adequately, but its efficacy is still unclear.