The largest CyberKnife® experience for pancreatic carcinoma patients has been gained by the Stanford group, which has applied this method as a single palliative fraction for inoperable patients, as well as using it as radiosurgical boost treatment in conjunction with 5FU-IMRT in a more aggressive phase II treatment protocol (17,18). Other groups have used fractionated CyberKnife® radiosurgery (2-5 treatments) instead of single fraction CyberKnife® treatment, to provide better radiobiologic sparing of the adjacent duodenum and other closely approximated GI tissues.
The Stanford single fraction CyberKnife® experience describes a dose escalation trial, with an impressive 100% local control and absence of grade III GI toxicity, achieved at the 25 Gy level (17). Unfortunately, the more aggressive Stanford combined 5FU-IMRT-CyberKnife® boost combined regimen (18) did not meaningfully improve the survival result compared with historical controls (9, 10, 11, 12), and did result in a greater incidence of grade III GI toxicity compared with their single fraction CyberKnife® only regimen.
Pancreatic Carcinoma
Written by Donald B. Fuller, M.D. – Radiation Oncologist