The prevalence of pre-cancerous masses in the colon is the same for average-risk patients who are 40 to 49 years of age and those who are 50 to 59 years of age, reports a new study in Gastroenterology, the official journal of the American Gastroenterological Association (AGA) Institute.
Currently, standard protocol recommends screening patients age 50 and over for colon cancer based on the increasing incidence of colon cancer at that age. Because observational studies have shown that it takes a decade for pre-cancerous growths, or adenomas, to develop and progress to cancer, the increase in colon cancer prevalence in the over-50 age group, in fact, may be the result of undetected adenomas that were present in the individuals in their 40s.
Investigating this hypothesis, a team of researchers, led by Drs. Alfred I. Neugut and Andrew Rundle from Columbia University Medical Center, compared colonoscopy results, broken down by age group. Analyzing records from a centralized digital medical record system provided by EHE International, the team reviewed 553 screening colonoscopies for patients ages 40 to 49 and 352 screening colonoscopies for patients ages 50 to 59. Individuals who could be deemed "high-risk" because of a family history of colon cancer, a personal history of inflammatory bowel disease or any malignancy other than skin cancer were excluded from the sample.
Of the records reviewed, in the 40 to 49 age group, 79 patients, or 14 percent, had one or more adenoma. Similarly, the 50 to 59 age group had 56 patients, or 16 percent, with one or more adenoma.
"Our results support the theory that adenomas, which later may lead to cancer, form at an age earlier than we screen for today," said Alfred I. Neugut, MD, PhD, professor of medicine and epidemiology at Columbia University Medical Center and head of cancer prevention and control for the Herbert Irving Comprehensive Cancer Center of Columbia University Medical Center and New York-Presbyterian Hospital. "With this information in hand, it is logical to think that if we were to recommend screening for colon cancer at age 40, we may be able to decrease its prevalence even further and save more people from having to battle the disease."
Though the number of adenomas was relatively similar in the two age groups, there was a doubling in the prevalence of abnormal cell growth, or advanced neoplasia, in the 50 to 59 age group versus the 40 to 49 age group. While not statistically significant, in the 40 to 49 age group, 11 patients, or 2 percent, had an advanced neoplasm, and in the 50 to 59 age group, 13 patients, or 4 percent, had an advanced neoplasm.