It's very simple. The colon isn't fixed - it moves and radiating a 'moving target' is difficult. The rectal area, which is what you are probably referring to, is fixed -it isn't constantly moving so yes, it can be radiated. Also, the pelvic region is rich in lymph nodes and to help stop local spread, radiation for rectal cancer is usually rxd for stage II and above. In addition, radiating the colon is rough. Some portions of the colon for the rectal cancer patient get radiated and the collateral damage can be brutal. Radiation is not solely used to shrink a tumor. It is also used, in circumstances where clean margins were not able to be obtained to provide that 'extra' measure of safety - i.e. kill any stray cancer cells. Trust me, if the rad onc doesn't feel your husband needs radiation - be happy.
Redtexa5 - yes entire pelvic radiation is not uncommon. Rectal cancer patients who receive traditional radiation, contrary to popular belief, generally do not have radiation solely aimed at the tumor. The lymph nodes are also radiated and, because of radiation 'scatter', a large portion of the pelvis is also radiated. It's actually quite common for damage to the vaginal area, the bladder as well as portions of the large intestine (and sometimes the small intestine as well). Also want to clarify that no, the rectum is NOT considered part of the colon. It has a definite beginning and end and is classified as such. It is entirely different from the colon. While yes, one reason radiation is used is to shrink the tumor it is by far not the only reason. Studies have concluded that for the rectal cancer patient, radiation significantly improves local recurrences - actually a more important reason that merely shrinking the tumor. In addition, most rectal cancer patients do end up losing most, if not all of their rectum, even when the tumor is higher up so while shrinkage may be of more significance to the low lying rectal cancer patient, it just isn't as important to those patients whose tumor lies higher up. Even in cases where the tumor is nothing more than a scar - generally speaking the entire rectum is removed.
Dx 2006 IIA rectal cancer
6 wks rad/Xeloda
1st attempt transanal excision 11/06
11/17/06 XELOX 1 cycle
5 mths Xeloda only - blood clots 1/07
transanal excision 4/20/07 path-NO CANCER CELLS!
NED now and forever!
Perform random acts of kindness