282 Background: Ampullary cancer outcomes have been reported to compare favorably with pancreatic and biliary malignancies. Consensus guidelines on the optimal adjuvant management after resection in these patients remain unclear. Propensity score matching was used to compare the outcomes of patients with ampullary cancer receiving or not receiving radiation therapy (RT) from the Surveillance, Epidemiology, and End Results (SEER) database. Methods: Patients with a diagnosis of ampulla of vater carcinoma who underwent curative intent surgery were identified within 17 SEER registries from 1998-2008. Patients with M1 disease or follow up less than 5 months were excluded. Data on patient characteristics such as age at diagnosis, race, tumor characteristics including TNM staging and histologic subtype, and survival outcomes were extracted and compared between patients who received adjuvant RT and those who did not. Propensity score matching was used to minimize treatment selection bias within the specified characteristics and estimate the impact of RT on median survival times (MST). Matching algorithms used validated Mahalanobis nearest neighbor methods based on conditional probabilities of receiving RT. Results: Of the 1782 patients identified, 490 (25%) were treated with adjuvant RT: 318 (65%) T3/4 and 333 (68%) N1. Cox regression with propensity score analysis for patients with RT showed an overall decrease in survival time by 3.67 months (p<0.05). Propensity score analysis showed slightly worse survival in patients who received RT compared to those who did not (MST 2.7 vs. 3.0 years, respectively, p=0.04). There was a trend towards a survival benefit with RT in a subgroup of patients over the age of 66 years with T2N0 tumors (MST 4.7 vs. 2.7 years, respectively, p=0.14). Survival outcomes analyzed by other T and N stages were not statistically significant. Conclusions: Adjuvant RT does not confer a survival benefit in resected ampullary cancers as studied in the propensity-score adjusted SEER patient population. Further studies should be conducted in order to elucidate the role of adjuvant RT for ampullary cancers.
Effect of prior cancer on survival outcomes for patients with pancreatic adenocarcinoma: a propensity score analysis
