I think it is very important to consider the risks of deciding to turn down a PEG.

Although in an emergency, many major CCC's can put a PEG in without losing any treatments, a break in treatments due to adverse side-effects is undesirable and may lead to a poorer outcome.

In most case additional doses can not be added to offset the SCC re-population that can occur during a break in treatment.

Several recent clinical pilot studies using OPET (PET/CT) studies of SCC tumors (primary & Lymph secondary) have found that cancer cell re-population seems to begins after just two days of a break in treatment when the cumulative radiation dose is below 6gy and within five days of a break in treatment if the cumulative dose is below 46gy.

18-F-FLT PET/CT scans and 18F-FDG PET/CT scans were obtained at a total dose of 2, 6, 10, 20, 30, 40, 50, or 60 Gy (i.e., after radiotherapy) to provide a range of Total Dose points for assessment of cell proliferation.

Scans also compare 18F-FLT with 18F-FDG with regard to their ability to differentiate residual tumor from inflammation.

The newer OPET (CT/PET) scanners using F-FLT instead of F-FDG tracer can differentiate between cancer re-population and inflammation.

Apparently studies are also being planned to determine probable difference in HPV- verses HPV+ breaks in treatment since HPV+ SCC is thought to be more sensitive to RT.