Although I have not had experience with chemo affecting my digestive system or causing any kind of intense pain, I will add my .02 to the argument for chemo.
When they do surgery to take out the tumor and then a good chunk of the colon around the area that the tumor was found... this is done with the goal of a "cure". Stage 1, 2 and 3 are all considered candidates for cure... but of course there are no guarantees. The higher the stage, the greater the chance of the cancer coming back. So the oncologists/doctors WILL treat aggressively since there is a chance of curing. Stage IV (when the cancer has spread to another organ/area of the body from the original site) is incurable, so that treatment is for stabilizing and/or the attempts to shrink any tumors. Depending on where they are, surgery may be an option, hence why you can hear of people having multiple surgeries over their lifetime... chasing down tumors and removing them. They are also usually on some form of chemo or radiation treatment to keep the growth under control. But if one is diagnosed as Stage 1, 2 or 3, then the possible cure will come with aggressive treatment and not taking any of the stages lightly.
Right now, her scans look good. The margins are good. The surgeon is feeling pretty confidant that s/he has gotten all of it and didn't leave any part of the tumor behind. This is all good news and does give everyone some breathing room. BUT, the good news is good for as much as our medicine/technology can do. The PET/CAT scans are fabulous tools... but they can only see tumours/cancer cell clusters that are a certain size or larger. For instance, they can not detect or see single cancer cells. A PET scan shows active cells, which indicate cancer in the body. This can also indicate other things (IE: scar tissue, infection, etc), so it does take an experienced radiologist to read the scans and determine what is a cancer and what might be something else. But since none of the technology we have today can detect single cancer cells that are roaming around our blood streams, there is no way of knowing if a Stage 1, 2 or 3 patient will have a recurrence or not. If they do, it will be because one or more of these floaters will have taken root somewhere in the body... most common areas for colon cancer spread is the liver and/or the lungs. It is possible to be elsewhere, but those are the two most common areas.
The post surgery chemo is important, because you want those single floaters to be killed off before they can take root anywhere. You will never know for sure if you got them, other than you don't come down with a recurrence. But you certainly will know if they are left alone to thrive... because they will land and take root at some point, as well as create new cancer cells. To me, it's a no-brainer... if I was a Stage 1-3 (I was diagnosed as Stage 3 when they first found the cancer), I would do everything possible to kill off any cancer cells left in my body. Just the surgical procedure of removing the (in my case) single tumor, could be enough to leave some cells from the tumor behind. As it is, I did have the post surgery chemo and within a year we found small tumors in my lungs. What we don't know is if they were always there but just too small to detect on the scans, or if this was post surgery and some floaters found their way to my lungs. Either way, I'm a Stage 4 now, so my treatment is now to stabilize and keep everything stable.
If your sister can, in any way, avoid becoming a Stage 4, then my recommendation is that she do it. The chemo she was on obviously caused her a lot of discomfort and pain, so she should have a talk with her oncologist and ask if there is a different chemo she could try. There are a good 4 or 5 chemos they use for colon cancer. If her oncologist says no, she has to use the one that she was on, then I would suggest going to a different oncologist and get a second, or even a third opinion.
Cheryl from Vancouver