I was told the same about HBO.
As I recall the expression used was "Like throwing gasoline on a fire".

I believe this opinion came from Stephen, a research PHd who was affiliated with my treatment CCC but from Sanford-Burnham, an associated NIH Basic CC Research Institute.

Apparently there is an opinion that HBO might be risky if there is evidence of some OC (or other cancer) still lurking around.

I don't know if this is mainstream thinking or not.