Most colorectal cancers arise from adenomatous polyps, but the effects of colorectal cancers family history on adenoma risk are not well known.
This issue is clinically relevant since several medical societies currently recommend earlier and more rigorous colorectal screening for individuals with a strong family history of colorectal cancers.
Dr Deborah Neklason and colleagues from Utah, USA performed colonoscopies in 236 first-, second-, and third-degree relatives of 40 index colorectal cancers cases.
The cases arose from 6 large kindreds selected from a large population database.
The kindreds were selected for significantly greater risk of colorectal cancers compared with the overall population.
|37% of relatives had adenomas on colonoscopy|
|American Journal of Gastroenterology|
Known hereditary colon cancer syndromes were clinically and genetically excluded.
The researchers found that 37% of relatives had adenomas on colonoscopy.
The average age of diagnosis for colon cancer was 63 years, and advanced adenomas was 56 years.
Independent predictors of adenomatous polyps in the relatives were advancing age, male gender, and greater degree of relation to colorectal cancers cases.
The team found there was no significant predilection of colorectal tumors for the right or left colon.
A higher degree of relationship to colorectal cancers cases was a significant predictor of having simple and advanced adenomas, but not hyperplastic polyps after adjustment for age and gender.
Dr Neklason’s team concluded, “These data support the current recommendations for colonoscopy starting before the age of 50 years in individuals with a strong family history of colorectal cancers.”