Should a brother receive a colonoscopy (colo) earlier if his sister was diagnosed with colon cancer at age 45?

From the Guidelines

A brother of a sister diagnosed with colon cancer at age 45 should receive colonoscopy screening earlier, specifically at age 35 or 10 years before the age at diagnosis of the youngest affected relative. This recommendation is based on the latest guidelines from the AGA clinical practice update on risk stratification for colorectal cancer screening and post-polypectomy surveillance, published in 2023 in the journal Gastroenterology 1. The key points to consider in this scenario include:

• The increased risk of colorectal cancer in first-degree relatives of patients with the disease, particularly when the relative was diagnosed before age 50
• The recommendation to start screening at age 40 or 10 years before the age at which the relative was diagnosed, whichever comes first
• The preferred screening method is colonoscopy, which should be repeated every 5 years if normal
• Early screening allows for detection and removal of precancerous polyps before they develop into cancer, or identification of cancer at an earlier, more treatable stage, thereby reducing morbidity, mortality, and improving quality of life. Some important considerations for the brother include:
• Consulting with his healthcare provider to establish an appropriate screening plan based on his personal and family history
• Being aware of the signs and symptoms of colorectal cancer and seeking medical attention if any concerns arise
• Maintaining a healthy lifestyle, including a balanced diet, regular exercise, and avoiding tobacco and excessive alcohol consumption, to reduce the risk of developing colorectal cancer. The brother should prioritize his health and take proactive steps to reduce his risk of developing colorectal cancer, given his family history and the increased risk associated with a first-degree relative diagnosed with the disease at a young age, as supported by the latest evidence from 1.

From the Research

Risk Factors for Colon Cancer

• A positive family history is one of the most common risk factors for colon cancer, with the risk varying from moderately increased when a first-degree relative has colon cancer to high when a first-degree relative is diagnosed at an age less than 50 years or there are two first-degree relatives with large bowel malignancy 2
• The risk of colon cancer is extreme in the rare colon cancer syndromes of familial adenomatous polyposis and hereditary nonpolyposis colon cancer 2

Screening Strategies

• The extensive characterization of familial occurrence of colon cancer has led to specific screening strategies for each of these levels of familial risk 2
• Surveillance colonoscopy is recommended at 2- to 3-year intervals beginning 8 years after diagnosis of inflammatory bowel disease (IBD) 3
• Recent colonoscopy (within 36 months) is associated with a reduced incidence of CRC in patients with IBD, and lower mortality rates in those diagnosed with CRC 3

Aspirin Use and Colon Cancer Risk

• Regular use of aspirin was associated with a significantly lower risk of CRC at or after age 70 years compared with nonregular use, but only among aspirin users who initiated aspirin use before age 70 years 4
• Initiating aspirin use at an older age was not associated with a lower risk of CRC 4

Colonoscopy Surveillance

• Colonoscopy surveillance for high risk polyps does not always prevent colorectal cancer, with approximately 1.8% of patients developing CRC at the polypectomy site within a median of 4.2 years 5
• Increasing age, polyp size, male sex, right-sided location, high degree of dysplasia, higher number of polyps resected, and piecemeal removal were associated with an increased risk for CRC development at the same site as the index polyp 5

Prevention of Colorectal Adenomas and Cancer

• There is combined evidence from three randomized trials that aspirin significantly reduced the recurrence of sporadic adenomatous polyps 6
• Nonsteroidal anti-inflammatory drugs had a greater proportional reduction in the number of colorectal adenomas compared with those in the control group in patients with familial adenomatous polyposis 6