Blood Test Detects Stage 3 Colon Cancer in Asymptomatic Woman Three Years Before Next Scheduled Colonoscopy

Kim Turner, a physician assistant in Alaska, received a positive result from a blood-based colorectal cancer screening test in 2025 at age 61. The Shield test by Guardant Health detected cancer three years before she was scheduled for her next colonoscopy. Turner had her first colonoscopy at age 50, which found a one-centimeter precancerous polyp.

Her follow-up colonoscopy at age 54 was clear. Her gastroenterologist told her she did not need another colonoscopy for 10 years. She has no family history of cancer, obesity, or smoking. The Shield test returned positive.

A follow-up colonoscopy confirmed adenocarcinoma in a three-centimeter section of her sigmoid colon. Turner had no rectal bleeding or abdominal pain. She experienced very mild and intermittent constipation that doctors attributed to an unrelated condition.

"I effectively had no symptoms," Turner said. " Shortly after diagnosis, Turner underwent surgery to remove the cancerous mass along with 28 lymph nodes. One of the lymph nodes tested positive for cancer.

Minor vascular involvement also was present. These findings classified her as Stage 3. At the time of the interview, Turner was in the middle of a twelve-week chemotherapy regimen. "If I would have waited three years, very different story.

Very different," Turner said. " Colorectal cancer is the second leading cause of cancer-related death in the United States. If caught early, the five-year survival rate exceeds 90 percent. More than 45 million eligible Americans are due or overdue for colorectal cancer screening.

Only 20 to 40 percent of patients follow through with the entire colonoscopy process. Guidelines for average-risk adults who receive a clean colonoscopy result recommend returning in up to 10 years. Shield is the first and currently only blood-based colorectal cancer screening test with FDA approval for average-risk adults 45 and older.