5-fluorouracil-based chemoradiation in unresectable pancreatic carcinoma: Phase I-II dose-escalation study.

PURPOSE: A Phase I-II dose-escalation study was performed to evaluate the possible impact of the dose on response, toxicity, pain relief, and outcome in patients with unresectable pancreatic carcinoma.

METHODS AND MATERIALS: A total of 50 patients entered the study. The external beam radiotherapy (RT) dose was 39.6 Gy in the first 15 patients, 50.4 Gy in the next 15 patients, and 59.4 Gy in the remaining 20 patients, at five 1.8-Gy fractions weekly. During external beam RT, patients received concurrent continuous infusion of 5-fluorouracil (1000 mg/m(2) on Days 1-4 and 21-24). Patients were evaluated for toxic reactions, local disease control, survival, and pain relief.

RESULTS

No treatment-related deaths occurred from acute toxicity. Four patients required a temporary treatment interruption because of acute hematologic (2 patients) or GI (2 patients) toxicity, not correlated with the delivered RT dose. Three patients (6%) developed late toxicity (duodenal ulcer in 2 and duodenal stenosis in 1). All patients who developed late toxicity had received a dose of 59.4 Gy. At univariate analysis, only the RT dose correlated significantly with the incidence of late toxicity (at 2 years, 39.6-50.4 Gy resulted in 0% and 59.4 Gy resulted in 58.2%; p = 0.023). At multivariate analysis, the RT dose also showed a trend with the incidence of late side effects (p = 0.052). Overall, 6 patients had a partial response (12%) and 44 (88%) had no change. The overall response rate was 8.0% (95% confidence interval, 1.5-20.5%). The rate of response was not different in the three groups. In-field locoregional disease progression was seen in 7 patients (14.0%). Distant relapse was documented in 34 patients (68.0%). None of analyzed variables, in particular, the RT dose delivered, showed a statistically significant correlation with objective response, local control, incidence of metastasis, disease-free survival, or overall incidence of pain symptoms after therapy. The whole group median survival was 9 months. The actuarial survival rate at 1, 2, and 3 years was 31.3%, 2.8%, and 0.0%, respectively. None of analyzed parameters correlated significantly with survival at univariate or multivariate analysis.

CONCLUSION

In a Phase I-II study, the association of high RT doses with the incidence of severe toxicity in the treatment of unresectable pancreatic carcinoma was confirmed. Furthermore, this dose-escalation study did not document a clearcut correlation, using 5-fluorouracil-based chemoradiation, between the radiation dose and clinical outcome.