The death of actor Kirstie Alley, who only recently received a colorectal cancer diagnosis, has brought renewed attention to the importance of screening, which is key to treating colorectal cancer early, Paul E. Oberstein, MD, a medical oncologist at NYU Langone Health’s Perlmutter Cancer Center, tells Inside Edition.

“It’s hard to detect if someone has not had any kind of screening studies because the colon’s inside the body,” says Dr. Oberstein, also an associate professor in the Department of Medicine at NYU Grossman School of Medicine and assistant director of the Pancreatic Cancer Center at Perlmutter Cancer Center. “Something can grow in the colon to quite a large size before someone will have symptoms such as back pain.”

Watch more on Inside Edition.