i work for gastroenterology and it seems every patient has the same fear as you. So that fear is actually normal to have. You probably just have internal hemorrhoids. Maybe a fissure if you are on the constipated side. If you are totally irregular, alternating between constipation and diarrhea, they will say you need to be on miralax (that is recommended for both constipation and diarrhea). For cramping, they can prescribe bentyl, but that takes a full 3 months before it desensitizes the nerves enough to not feel cramping. THey will say local hygeine care and plain white toilet paper. You don't have colon cancer. I would bet a million bucks on it. I doubt you have diverticulosis either. And i doubt you have any inflammatory condition going on either. The best thing you can do for yourself is eat clean, whole foods and keep it diverse, avoid preservatives. Lots of vegetables, low fat, low sodium. Healthy fats are good such as avocado and extra virgin olive oil and extra virgin unrefined coconut oil. Exercise daily, nothing strenuous, just like a 20 minute walk a few times per day. Develop proper sleep routine. You will be fine.