James Van Der Beek recently announced that he was diagnosed with colorectal cancer - but what does the disease entail? "Colorectal cancer is a cancer that arises in your colon or your rectum," gastroenterologist Roshini Raj exclusively told Us Weekly on Monday, November 4. "So part of your large intestine." Here's more need-to-know information. Symptoms and Warning Signs Raj, who has not personally treated Van Der Beek, 47, shared that colorectal cancer can be present "without causing any symptoms" so it is crucial that everyone gets checked out and the best method is a colonoscopy.