At what age should a patient with a second-degree relative (family member) diagnosed with colon cancer at age 50 be screened for colon cancer?

From the Guidelines

For patients with a second-degree relative diagnosed with colon cancer at age 50, screening should begin at age 40, as this is the most recent and evidence-based recommendation from the US Multi-Society Task Force on Colorectal Cancer 1. The recommended screening method is a colonoscopy every 5-10 years, depending on findings and other risk factors. This recommendation differs from average-risk individuals who typically begin screening at age 45. Having a family history of colorectal cancer increases risk, even with second-degree relatives, though the risk is lower than with first-degree relatives. The age of diagnosis in relatives is also important - earlier diagnoses in family members suggest potentially higher genetic risk. After the initial screening, if results are normal, follow-up colonoscopies should typically occur every 5-10 years, but this interval may be adjusted based on findings such as polyps or other risk factors. Some studies suggest that the risk of colorectal cancer is increasing in younger individuals, and earlier screening may be beneficial 1. However, the US Preventive Services Task Force recommends routine colorectal cancer screening in average-risk adults aged 50 to 75 years, with varying recommendations for earlier screening in individuals with a family history of colorectal cancer 1. Patients should discuss their complete family history with their healthcare provider to determine the most appropriate screening schedule for their specific situation. Key considerations include:

• Age of the patient and their relatives
• Presence of other risk factors, such as polyps or genetic syndromes
• Results of previous screenings and colonoscopies
• Overall health and medical history of the patient. It is essential to weigh the benefits and risks of screening, including the potential for false positives and unnecessary procedures, against the potential benefits of early detection and prevention of colorectal cancer 1.

From the Research

Screening Guidelines for Patients with a Family History of Colon Cancer

The patient in question has a second-degree relative diagnosed with colon cancer at age 50. According to the studies, the risk of colorectal neoplasia is increased in second-degree relatives of patients with colorectal cancer 2.

Age to Start Screening

• The study published in The Journal of family practice in 2010 recommends that screening should begin at 40 years of age for patients with a family history of CRC or AP in at least 1 first-degree relative or CRC in at least 2 second-degree relatives 3.
• However, the U.S. Multi-Society Task Force on Colorectal Cancer does not provide specific recommendations for second-degree relatives, but it does recommend average-risk screening options for persons with a single first-degree relative diagnosed at ≥60 years with CRC or an advanced adenoma, starting at age 40 years 4.
• Another study published in Acta gastro-enterologica Belgica in 2005 recommends average risk colon cancer screening starting at age 40 years if a person has a first degree relative with colon cancer, but it does not provide specific recommendations for second-degree relatives 5.
• A study published in American family physician in 2018 recommends that individuals who have a first-degree relative with colorectal cancer or advanced adenoma diagnosed before 60 years of age or two first-degree relatives diagnosed at any age should be advised to start screening colonoscopy at 40 years of age or 10 years younger than the earliest diagnosis in their family, whichever comes first 6.

Screening Interval

• The study published in The Journal of family practice in 2010 recommends routine options and follow-up intervals for patients who have a first-degree relative diagnosed with CRC or AP after 60 years of age or 2 or more second-degree relatives with CRC, which include any of the following 3 regimens: annual high-sensitivity fecal occult blood testing, sigmoidoscopy every 5 years combined with high-sensitivity fecal occult blood testing every 3 years, or screening colonoscopy every 10 years 3.
• The U.S. Multi-Society Task Force on Colorectal Cancer recommends that persons with a family history of CRC or a documented advanced adenoma in a first-degree relative age <60 years or 2 first-degree relatives with these findings at any age are recommended to undergo screening by colonoscopy every 5 years, beginning 10 years before the age at diagnosis of the youngest affected relative or age 40, whichever is earlier 4.

Since the provided evidence does not directly address the screening recommendations for a patient with a second-degree relative diagnosed with colon cancer at age 50, the above information is based on the available data for first-degree and second-degree relatives.