I had pelvic radiation for rectal cancer (adenocarcinoma) but it's basically the same thing. First of all, with regards to the chemo - will she be having a port placed and getting her chemo that way OR will she be on the oral form. If a port, then she should have some open front shirts to make that access easier.
As far as the bottoms go, I was adament when I had my treatments about staying clothed. As long as there are NO metallic anythings, they just let me scootch my gauchos/shorts/ etc. down a little and that was that. After radiation, cotton is the best.
Please PM me as there are MANY things that your friend needs to know about pelvic (for rectal, anal, cervical - all the same in this respect) radiation that, unfortunately, the oncs do NOT tell the patients. I can also send you the link for a anal squamous cell online support group. I also belong to that group and they are wonderful! But, again there are some serious side effects that can be minimzed or even eliminated (radiation side effects) that she needs to be very aware of right from the get go.
Jaynee