Intensified adjuvant therapy for pancreatic and periampullary adenocarcinoma: survival results and observations regarding patterns of failure, radiotherapy dose and CA19-9 levels.

Purpose: Primary endpoints were 1. To determine if, in the context of postoperative adjuvant therapy of pancreatic and nonpancreatic periampullary adenocarcinoma, continuous infusion (C.I.) 5-fluorouracil (5-FU) and leucovorin (Lv), combined with continuous-course external-beam radiotherapy (EBRT) to liver (23.4-27.0 Gy), regional lymph nodes (50.4-54.0 Gy) and tumor bed (50.4-57.6 Gy), followed by 4 months of C.I. 5-FU/Lv without EBRT could be given with acceptable toxicity. 2. To determine an estimate of disease-free and overall survival (DFS, OS) with this treatment in this context. Secondary endpoints were 1. To observe the effects of therapy at two different dose levels of irradiation, and 2. To observe for correlations among DFS, OS and CA 19-9 levels during therapy.

Methods: Patients received C.I. 5-FU 200 mg/m2 and Lv 5 mg/m2 Monday through Friday during EBRT, and 4 cycles of the same chemotherapy without EBRT were planned for each 2 weeks of 4, beginning 1 month following the completion of EBRT. Therapy was to begin within 10 weeks of surgery and patients were monitored for disease recurrence, toxicity, and CA 19-9 levels before the start of EBRT/5-FU/Lv, before each cycle of C.I. 5-FU/Lv, and periodically after the completion of therapy. There were two EBRT dosage groups: Low EBRT, 23.4 Gy to the whole liver, 50.4 Gy to regional nodes and 50.4 Gy to the tumor bed; High EBRT, 27.0 Gy to the whole liver, 54.0 Gy to regional nodes, and 57.6 Gy to the tumor bed.

Results: 29 patients were enrolled and treated (23 with pancreatic cancer, and 6 with nonpancreatic periampullary cancer). Of these, 18 had tumor sizes > or = 3 cm and 23 had at least one histologically involved lymph node; 6 had histologically positive resection margins. Mean time to start of EBRT/5-FU/Lv was 53 +/- 2 days following surgery. The first 18 patients were in the Low EBRT Group and the last 11 in the High EBRT Group. Toxicity was moderate and manageable, including a possible case of late radiation hepatitis. Median DFS was 8.3 months (pancreatic cancer patients 8.5 months) and OS was 14.1 months (pancreatic cancer patients 15.9 months). Among patients with pancreatic cancer, results were similar for the Low and High EBRT Groups (DFS: 8.3 vs. 8.6 months; OS: 14.4 vs. 16.9 months, respectively). With a mean follow up of 2.6 +/- 0.3 years for the surviving patients and a minimal follow-up of 2.5 years, 27 of 29 pts have relapsed and 25 pts have died. A rise in CA 19-9 levels preceded clinical relapse by 9.1 +/- 1.5 months. Time to first relapse by site showed inverse correlation with dose of radiotherapy to that site: peritoneal (5 +/- 1 month), hepatic (7 +/- 0.9 months), regional nodes/tumor bed (9.6 +/- 1.8 months). Mean postresection CA 19-9 level was 63.3 +/- 16.2 U/ml. Postresection CA 19-9 values did not correlate with survival, margin status, or with the identification of metastatic carcinoma in resected lymph nodes. However, among patients with histologically involved nodes in the resected specimen, postresection CA 19-9 values did correlate with the number of positive nodes identified (p = 0.05).

Conclusions: Although toxicity was acceptable, survival results were not improved over those seen with standard adjuvant treatment. Most patients relapsed before the planned chemotherapy cycles were completed, or within 100 days thereof, suggesting disease resistance to C.I. 5-FU/Lv as used in this study. Although this regimen is not recommended for further study, the doses of EBRT utilized may be suitable for evaluation with other chemotherapy combinations. Postoperative CA 19-9 levels did not correlate with survival, but did correlate with the number of histologically involved lymph nodes found in the resected specimen among node-positive patients. Moreover, rising CA 19-9 levels anticipated ultimate clinical failure by 9 months.