O. Kantor1, W. Lutfi2, M. S. Talamonti2, C. H. Wang3, D. J. Winchester2, R. A. Prinz2, M. S. Baker2 1University Of Chicago,Department Of Surgery,Chicago, IL, USA 2Northshore University Health System,Department Of Surgery,Evanston, IL, USA 3Northshore University Health System,Center For Biomedical Research Informatics,Evanston, IL, USA
Introduction:
The benefit of adjuvant external beam radiation following a margin negative resection in early stage pancreatic cancer has not been definitively determined.
Methods:
We queried the National Cancer Data Base for patients with pathologic stage I-II pancreatic adenocarcinoma who underwent resection between 1998 and 2011. Patients receiving neoadjuvant therapy and those with R1or R2 resection margins were excluded. Multivariate Cox-regression modeling was used to analyze stage-specific survival.
Results:
25,012 patients with stage I-II pancreatic adenocarcinoma underwent upfront surgical therapy and had a margin negative resection during the period studied. 1683 (6.7%) were pathologic stage IA, 3055 (12.2%) stage IB, 5850 (23.4%) stage IIA, and 14424 (57.7%) stage IIB. 4909 (19.6%) patients received adjuvant chemotherapy, 9367 (37.5%) adjuvant chemotherapy and radiation (chemoRT), and 10736 (42.9%) received no adjuvant therapy. ChemoRT utilization increased with increasing stage (25.3% in stage IA vs 41.0% in stage IIB, p<0.001). ChemoRT was more common at community than academic centers (46.3% vs 33.5%, p<0.001) and more common at low volume than high volume centers (44.6% vs 31.9%, p<0.001).
Cox-regression adjusted for age, race, comorbidities, facility type, location, and volume, type of pancreatectomy, and grade was used to estimate stage-specific survival for patients undergoing treatment between 1998-2006. Treatment at a high volume center was associated with decreased mortality (HR 0.74-0.81, p<0.04) across all stages. Age ≥70 (HR 1.2-1.3, p<0.01) and higher grade (HR 1.55-1.82, p<0.01) were associated with higher risk of mortality at all stages. ChemoRT was associated with a benefit in median overall survival over chemotherapy alone in all stages. That benefit was statistically significant in patients with stage IIA (23.4 vs 19.8 months, p=0.01) and stage IIB (18.6 vs 16.0 months, p<0.01), but not stage IA (37.4 vs 31.2 months, p=0.28) or stage IB (25.9 vs 20.5 months, p=0.06) [Figure 1].
Conclusion:
Addition of radiation to adjuvant chemotherapy after margin negative resection of pancreatic adenocarcinoma provides a survival benefit in patients with pathologic stage II disease and should be considered as adjuvant therapy in these patient groups.
