You probably know that when the Philadelphia skyline glows pink in October, it's intended to raise breast cancer awareness.

When it turns blue early next month, Marianne T. Ritchie wants you to think about colon cancer — or more specifically, about getting a colon cancer screening test.

This is the third year that Ritchie, a gastroenterologist and liver specialist at Thomas Jefferson University, has organized the blue lights campaign.  The participating companies and buildings, which will go blue the second week of March, include PECO, Two Liberty Place, FMC Tower, Cira Center, the Lit Brothers building, the Ben Franklin Bridge, and Boathouse Row. In Harrisburg, the State Capitol will have blue lights on March 6, 7, and 10.

"For 30 years, I have practiced gastroenterology and performed colonoscopy," says Ritchie. "Colon cancer is a clear and present danger. Studies show colonoscopy decreases death rates from colon cancer, but people who don't have symptoms often delay this important screening test."

Colorectal cancer is the second leading cause of cancer death in the United States. Because the risk increases with age, screening is recommended beginning at age 50. The goal of screening is to detect precancerous polyps before they become malignant, so they can be removed.

Colonoscopy is considered the gold standard test, but there are other effective screening tools. Simple take-at-home stool tests, which detect hidden blood in the stool, are less invasive and don't require the unpleasant colon-cleaning prep that make people dread a colonoscopy. An exam with a sigmoidoscopy  uses a scope to check the rectum and lower part of the colon.

"I am honored to belong to the National Colorectal Cancer Round Table of the American Cancer Society," Ritchie said. "Our slogan is,'The best test is the test that gets done!'"

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