Colorectal cancer screening improves survival in seniors

Oct 16 2007

As people get older, their risk of developing polyps and colorectal cancer increases. Currently, there is no clear evidence or established guideline for the upper age limit for colorectal cancer screening by colonoscopy.

Two new studies presented at the American College of Gastroenterology's 72nd Annual Scientific Meeting suggest continued colorectal cancer screening among healthy elderly Americans.

Dr. Matthew M. Baichi and his colleagues from the University of Buffalo and the VA Western New York analyzed the results of 587 colonoscopies performed at their institution in 2004. Fifty-six patients were age 80 or older and 531 patients were younger than 80. Researchers collected data on the number and location of adenomas, histology, presence of advanced adenomas, and colon cancer.

In this Buffalo study, colorectal adenomas were detected more frequently in older patients. Adenomas were found in 35.7 percent of patients age 80 or older and 20.4 percent of patients younger than 80. There was a trend for more proximal advanced adenomas in patients over 80 (12.5 percent) compared to those younger than 80 (6 percent). After a 2.5-year follow-up, 72 percent of patients over the age of 80 were alive compared to 82 percent of patients between the ages of 70 and 79.

“While screening colonoscopy is controversial in patients over 80, age alone should not be a contraindication to colorectal cancer screening,” says Dr. Baichi. “The results of this study suggest screening colonoscopy should be considered in healthy elderly patients.”

In separate research conducted at Scripps Clinic in La Jolla, CA, Emily G. Singh, MD, Catherine T. Frenette, MD, and Williamson B. Strum, MD, found that screening colonoscopy improves survival in elderly patients. The critical question for these researchers was whether screening colonoscopy leads to earlier stage of colorectal cancer diagnosis in the elderly, and thus improves survival in older patients.

The Scripps analysis included 243 symptomatic and 113 asymptomatic patients diagnosed with colorectal cancer between January 2000 and December 2005. Patient records were obtained from the Scripps Green Hospital Cancer Registry. Patients were divided into two groups based on symptoms and by age and stage of disease at diagnosis. The stages of colon cancer were separated at a critical point: early stage (Stage 0 – IIB) and late stage (Stage III – IV). Researchers found 101 patients had stage I colon cancer, 105 patients were diagnosed with Stage II colon cancer, 72 with Stage III, and 61 patients had stage IV colon cancer. The survival rates of all patients were evaluated from the time of initial colon cancer diagnosis.

After a two and a half year follow-up, researchers found asymptomatic patients had significantly improved survival compared to symptomatic patients. There was a sustained difference in stage of disease favoring patients who were asymptomatic, for all ages between 50 and 84, suggesting a role for preventive screening even among those of advancing age. According to Dr. Emily Singh, “We conclude that there is a role for screening colonoscopy in asymptomatic individuals without significant comorbidities up to age 84.” Neither the American College of Gastroenterology nor any other guideline groups currently set an upper age limit for colorectal cancer screening by colonoscopy.