PATTERNS OF DISEASE RECURRENCE FOLLOWING DEFINITIVE THERAPY OF ADENOCARCINOMA OF THE PANCREAS USING SURGERY AND ADJUVANT RADIOTHERAPY - CORRELATIONS OF A CLINICAL-TRIAL

Purpose: Between 1980 and 1984, 26 patients with resectable adenocarcinoma of the pancreatic head were enrolled in a National Cancer Institute protocol evaluating intraoperative radiotherapy vs. standard therapy. Methods and Materials: After complete excision of their lesions, patients were observed (Stage I), or randomized to intraoperative radiotherapy vs. external beam radiotherapy (Stages II-IV). The intraoperative dose was 20 Gy in a single fraction using 9-20 MeV electrons. The external beam radiotherapy schema involved daily 150-180 cGy fractions to 45-55 Gy in 5-6 weeks. Chemotherapy was not used for primary disease but was administered off protocol for recurrent disease. Median potential followup for the trial was > 9 years, with a median patient survival of 18 months. Perioperative mortality was 27% (7 patients). Of the remaining 19 patients, one remains alive and without evidence of disease 9 years post-therapy. Twelve patients underwent autopsy and 2 required antemortem laparotomy; histopathologic evidence of disease recurrence was analyzed. Results: Of 15 patients evaluable for intra-abdominal control, 7 (47%) suffered local recurrences and 7 (47%) failed regionally, with 5 patients (35%) failing in both areas. Five patients (35%) developed peritoneal seeding. Of 13 patients evaluable for systemic disease, 8 (62%) suffered distant failure. There were no differences in outcome between intraoperative or external beam radiotherapy or observation in this subset of patients. Conclusion: This report is among the most rigorous descriptions of patterns of failure after resection of pancreatic cancer. It appears clear that advances in local control of this disease are unlikely to translate into increased survival in the absence of improved systemic therapy.