Article: Red flags for colorectal cancer in young adults

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What is this article about?

Only a small number of people are diagnosed with colorectal cancer under age 50. However, rates of colorectal cancer in young adults have more than doubled since 1995. The causes for this increase are unknown. Looking at medical records from a large health insurance database, researchers were able to identify four signs (“red flags”) for colorectal cancer in adults under the age of 50.

Why is this article important?

For patients at average risk of colorectal cancer, routine screening is recommended to begin at age 45. However, about half of patients with early-onset colorectal cancer (diagnosed before age 50) develop this cancer before routine screening is recommended. Compared to older patients, younger patients with colorectal cancer are also more likely to be diagnosed when the disease is more advanced and less likely to be curable.

Research on the signs of colorectal cancer has focused on diagnoses after age 50. A better understanding of the signs of early-onset colorectal cancer can lead to earlier diagnosis and improved survival.    

You can read more about the rise in colorectal cancer diagnoses in our XRAY review here.

Study findings

For this study, researchers looked at health records from a large US insurance database. Data from more than 5,000 patients with colorectal cancer before age 50 were included. Researchers looked for signs of colorectal cancer within three months to two years prior to a diagnosis.

For comparison, health records for a control group—a group of patients who did not have colorectal cancer but were similar in other ways (age, sex, other health factors)—were also searched for the same signs.

Researchers were able to identify the following four signs that occurred more often in the group of patients with colorectal cancer compared to the group without colorectal cancer: 

• rectal bleeding (which may be seen in stool)
• pain in the abdomen (belly)
• diarrhea
• anemia (not having enough red blood cells to carry oxygen to tissues), which is found by a blood test

While these symptoms might be due to other underlying conditions, it is important not to ignore these symptoms if they continue. Among these four signs, rectal bleeding was most commonly associated with developing colorectal cancer.

A person’s chance of developing colorectal cancer increased according to the number of symptoms they developed. Having one symptom increased the risk of having CRC two times, while having three or four symptoms increased the risk more than six times.

Some patients experienced long delays from the start of symptoms to diagnosis, especially those with fewer symptoms. This delay in diagnosis in young adults is close to twice the time to diagnosis in older people and may contribute to colorectal cancer in young adults being diagnosed at more advanced stages.

The study researchers concluded that healthcare providers and patients should be aware of these four red flags for colorectal cancer before age 50, especially in patients who may not be having routine screening.