Would colon cancer symptoms be present 10 days, go away for 2 weeks, then come back for a month straight? no rectal bleeding, blood in stool, black stool, vomiting, or fever - just constipation, rectal discomfort, and dull cramps all over the abdomen?

While usually cancer symptoms persist and worsen in time, there are times when they improve temporarily either because of treatment or because of natural processes, such as having a bowel movement when partially obstructed, cramps may resolve for a while. Not a reliable diagnostic or activity sign otherwise.

For constipation - You may take a fiber laxative like Metamucil and drink enough water daily so that your urine is colorless. For the long term you may try to increase your intake of fiber foods. Consult this site for fiber foods. http://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/high-fiber-foods/art-20050948 Wish you good health!