First, I am sorry that you have developed colon cancer. While no one will be able to tell you for sure why you developed it, I can give you a list of important risk factors that may have played a role in your case. When people develop colon cancer at a young age, there is almost always a genetic component. This doesn't mean that you inherited the colon cancer per se, it just means that your genes put you at higher risk for developing colon cancer. In addition, smoking, and a diet high in red meats and low in fiber can be associated with colon cancer. Birth control
pills do not increase you risk for colon cancer as best we can tell. There is some evidence that they may actually help reduce colon cancer risk.
i suggest that you schedule an appointment with your hematologist/oncologist. The two of you can discuss your future treatment plans to be able to cure or control your colon cancer. In addition, you can discuss what risk factors may have played a role in you cancer. If there are genetic issues suspected, then your close family members should be screened at a much younger age. In addition, if you have kids (regardless of any other risk factors), they should begin screening for colon cancer at age 35. Good luck.