If you’re under 50 years old and experiencing symptoms such as anemia, bloody stools, diarrhea, or stomach pain, you may want to get screened for colorectal cancer.

That’s because having just one of these symptoms is associated with an almost doubled risk of colorectal cancer (often shortened to colon cancer) in younger adults, or those ages 50 and younger. With two of these symptoms, the colon cancer risk more than triples. And with at least three of these symptoms, the risk is more than 6 times higher.

Colon cancer has increased by 50 percent among younger adults since the 1990s. It’s already the top cause of cancer-related deaths among men ages 50 and younger and No. 2 among women in that age group.

By 2030, it may be the leading cause of cancer-related deaths among all younger adults.

Knowing the symptoms that may be red flags for colon cancer, as well as when to get screened, is key to early detection and successful treatment.

Colorectal Cancer Symptoms in Younger Adults

It’s important to know that colorectal cancer doesn’t just happen to old people, says Peter Liang, MD, MPH, an assistant professor at the New York University School of Medicine in New York City. Celebrities in their 40s such as Chadwick Boseman and James Van Der Beek have had the diagnosis.

Colon cancer deaths also are decreasing among people older than 50 years old.

Why is this happening? Research has pointed to childhood exposure to a toxin produced by certain E. coli bacteria as a potential factor in early-onset colorectal cancer.

As for red flags, about 1 in 5 people with colorectal cancer experienced at least one of the following symptoms between three months and two years before their cancer diagnosis, and about half experienced them in the three months before their diagnosis.

Anemia

Iron-deficiency anemia occurs when your body does not have enough iron to produce red blood cells. These cells are important for removing carbon dioxide from your body and carrying oxygen to your tissues. When you are anemic, you may feel tired and out of breath.

Bloody Stools

A number of factors can lead to blood in your bowel movements. If you have a tumor or polyp in your colon, it may bleed into your digestive tract. This may make your stool black or dark brown. But you also may not notice blood in your stool at all.

Diarrhea

Inflammation in your colon can cause diarrhea, as can fluid from a tumor or a blockage.

Similar symptoms may include constipation, narrow stool, and a full feeling after a bowel movement, as though your bowels have not fully emptied.

Abdominal Pain

This pain may be sharp or feel like cramps in your belly that do not go away on their own.

Abdominal pain from colon cancer is more common on the left side of the body.

“Everyone, regardless of age, should recognize that symptoms such as ongoing abdominal pain and rectal bleeding, as well as lab tests showing anemia, could be a sign of colorectal cancer,” Dr. Liang says. “If you have any of these symptoms, you should talk to a physician.”

Who Should Be Screened for Colorectal Cancer?

The American Cancer Society recommends colorectal cancer screening for all adults once they turn 45 years old, even if they have no symptoms. If you have additional risk factors, your doctor may order a screening earlier.

Types of tests and screening include:

Colonoscopy In this common procedure, a doctor will insert a long, flexible tube in your rectum and use a video camera to inspect your large intestine for polyps or abnormalities. It does require a clean colon, and pre-procedure preparation is necessary. If the procedure shows no abnormalities, you likely can wait 10 years before another colonoscopy. A virtual colonoscopy, similar to a CT scan, also may be available.
Sigmoidoscopy Similar to a colonoscopy, this procedure examines only the lower left side of your colon, rather than the whole thing.
Stool DNA Test A doctor will examine a stool sample to see if DNA changes may indicate colon cancer. It is less effective in discovering polyps than a colonoscopy. Additional tests may be necessary if the test shows potential issues.
Fecal Blood Test Your stool will be analyzed in a lab to see if it contains blood. This test also does not always uncover polyps or cancer, and a follow-up test may be necessary.

Your blood itself may be screened as well.

Don’t Jump to Conclusions

Symptoms of colorectal cancer are not the same as a diagnosis. And seeing a doctor won’t necessarily lead to an invasive screening test, says Samir Gupta, MD, a gastroenterologist and professor of medicine at the University of California, San Diego.

“In many cases, a patient and doctor may decide that a diagnosis other than colon cancer is the likely cause and move forward with a diagnosis and treatment plan that does not include colonoscopy,” Dr. Gupta says.

If this treatment works within a month or two, additional cancer screening may not be necessary, he says.

“If the original treatment plan is not working, and symptoms persist, then colonoscopy should be strongly considered to rule out colorectal cancer,” Gupta says.

Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.

Resources

Fritz CDL et al. Red-flag signs and symptoms for earlier diagnosis of early-onset colorectal cancer. Journal of the National Cancer Institute. August 2023.
Siegel RL et al. Cancer statistics, 2024. CA: A Cancer Journal for Clinicians. January 17, 2024.
Peregrin T. Clinicians Struggle to Understand Dramatic Rise in Early Onset Colorectal Cancer. American College of Surgeons. December 4, 2024.
Vuik FE et al. Increasing incidence of colorectal cancer in young adults in Europe over the last 25 years. Gut. 2019.
Key Statistics for Colorectal Cancer. American Cancer Society. April 28, 2025.
Díaz-Gay M et al. Geographic and age variations in mutational processes in colorectal cancer. Nature. April 23, 2025.
Colorectal Cancer Signs and Symptoms. American Cancer Society. January 29, 2024.
Can Diarrhea be a Symptom of Colon Cancer. Mercy Medical Center. July 8, 2022.
Jones V. Cancer in the sigmoid colon: What it means when colon cancer is on the left side. MD Anderson Cancer Center. February 14, 2024.
American Cancer Society Guideline for Colorectal Cancer Screening. American Cancer Society. January 29, 2024.
Colon Cancer Screening: Weighing the Options. Mayo Clinic. January 8, 2025.
Colorectal Cancer Screening Tests. American Cancer Society. February 28, 2025.

Daniel Landau, MD

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Daniel Landau, MD, is a distinguished board-certified hematologist-oncologist with a career that has spanned two eminent institutions: the Orlando Health Cancer Institute and the Medical University of South Carolina. With a specialized interest in genitourinary oncology and hematology, he has been at the forefront of managing both benign and malignant conditions.

Dr. Landau is a pioneering figure in integrating advanced technology into oncology, having served as a director of telemedicine services. Under his leadership, multiple innovative systems have been designed and piloted, all with a singular focus: enhancing the patient experience.

Beyond his clinical and technological endeavors, Landau is deeply committed to medical education. He has dedicated significant time and expertise to nurturing the skills of medical students, residents, and fellows, ensuring that the flame of knowledge and compassion burns bright in the next generation of oncologists.

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4 Potential Red Flags for Early-Onset Colorectal Cancer