Several studies have evaluated SBRT for unresectable PCA. Early reports suggest excellent LC; however, a significant proportion of pts experience duodenal toxicity.

Stanford (ChangDT et al., Cancer 2009): 77 pts with unresectable PCA rcvd 25 Gy × 1 with CyberKnife SBRT. The 6- and 12-mo isolated LR rate was 5% and 5%, respectively. The PFS at 6 and 12 mos were 26% and 9%, respectively. The 1-yr OS was 21%. At 12 mos, the ≥G2 late toxicity was 25%, including 1 small bowel perforation (G4), 1 duodenal stricture (G3), and 3 gastric ulcers (G3).

Beth Israel Deaconess (MahadevanA et al., IJROBP 2010): 36 pts with unresectable PCA rcvd 24-36 Gy CyberKnife SBRT in 3 fx. Gemcitabine was given after SBRT. LC rate was 78%, and MS was 14.3 mos. 39% developed ≥G2 toxicity (25% G2, 14% G3); including 3 pts with vomiting and dehydration (G3) and 2 pts with GI bleed (G3).

John Hopkins, MSKCC, Stanford (HermanJ et al., Cancer 2014) 49 pts, rcvd 1 cycle gemcitabine, then 33 Gy in 5 fx, with 1-yr freedom from local progression (FFLP) 78%, MS 13.9 mos, with 11% grade 2 or more toxicity, 1 G5 GI bleed, 1 G3 bleed, 1 G3 ulcer.