This is controversial. RTOG 9704 randomized R0 and R1 PCA pts to CI 5-FU (250 mg/m²/d) CRT (50.4 Gy) and pre- and post-CRT with either additional 5-FU or gemcitabine. Among all eligible pts, there were no differences. In a preplanned subset analysis of pts with pancreatic head tumors, trends favored gemcitabine: MS was 20.5 mos vs. 16.7 mos, and 3-yr OS was 31% vs. 22%, but results were NSS (p = 0.09). The 3-yr LR was significantly better for the gemcitabine arm (23% vs. 28%). Updated 2012 results showed significantly worse survival in pts with CA 19-9 >90 U/mL, positive nodes, & RT quality assurance protocol deviations. (RegineW et al., JAMA 2008; BergerAC et al., IJROBP 2012)