Here's a link to an abstract of an article that addresses the issue of hyperbaric treatment and tumor growth. It is from PubMed, the government service of the National Library of Medicine and National Institutes of Health:

http://www.ncbi.nlm.nih.gov/entrez/...amp;list_uids=12841604&dopt=Citation

The bottom line, to quote from this article, published in 2003:

"In conclusion, the published literature on tumor angiogenesis mechanisms and other possible mechanisms of cancer causation or accelerated growth provides little basis for HBO2 to enhance malignant growth or metastases. A history of malignancy should not be considered a contraindication for HBO2 therapy."

Karen, your post makes me wonder if your dad is being treated at a comprehensive cancer center where a team-based approach is standard procedure, and all of the doctors are in fact in the same room to decide upon treatment protocols.
I was told by my rad oncologist that radiation should start within 6 weeks of the surgery. This is to give the surgery a chance to heal before starting the radiation. Hopefully, this will give you some time to consider the best course of action. Best, Sheldon