According to MD Anderson Cancer Center researchers, colon cancer treatment appears to vary significantly in the United States. Guideline-based treatment was most likely to be provided to patients with stage I disease (96%), when compared with patients with stage II (low risk, 66%; high risk, 36%), stage III (71%), or stage IV (73%) disease. Across all stages, factors associated with guideline adherence included:

Age.
Comorbidities.
Later year of diagnosis.
Insurance Status.

The study authors noted that the impact of non-adherence to guidelines on patient outcomes requires further research.

Abstract: Journal of Clinical Oncology, March  20, 2012.