Nobody ever wants to receive a cancer diagnosis. But when I found out I had poorly differentiated adenocarcinoma of the cecum — a type of colorectal cancer — in September 2012, I was somewhat relieved.

As someone who’d had ulcerative colitis since middle school, I’d been dealing with chronic diarrhea, frequent stomachaches and other digestive issues for more than 20 years. But after the birth of my second daughter in May 2011,...