Hi and welcome to the board.

I am sorry for your diagnosis, but I am glad you found us. We all have experience and knowledge to share with you and support you as you go through this journey.
A week worth of radiation, and then surgery the following week is NOT standard in the treatment of rectal cancer. Nor is 6 weeks radiation followed by 6 weeks of chemo. Radiation is documented in studies to give better results when given WITH chemo usually for the first and last weeks of treatment. However, this DOES NOT mean that you have a bad radiation oncologist or oncologist.-- I just wanted to point out the norm. Maybe there are circumstances with your tumor that warrant this regimen.
I have a few questions... Did they tell you what stage you are, or exactly how big the tumor is? Also, how far has it grown into the rectal wall? Did they tell you what the differentiation of the tumor is-- poorly, moderate, or well-differentiated (histology from the biopsy/pathology report)? Lastly, what agent was your oncologist planning to use if you went the route of radiation and chemotherapy? The standard is 5FU and Leucovorin, although the oral agent Xeloda IS starting to become the norm.
I'm SORRY if I sound like I'm beating you up with questions!!! I'm just curious so we can all try to help and support you better!!!
Lastly, I just want to encourage you to get a second or even a third opinion on how best to handle your situation and whether a colostomy is necessary.
Warm Regards,
CancerDad