Colorectal cancer is one of the most common and most preventable cancers in the United States. It is also one of the most treatable when found early, yet it remains the leading cause of cancer-related death in adults under 50, and the second leading cause overall.The good news is that awareness, routine screening, and knowing the warning signs can genuinely save lives.
This a reminder to pay attention to our colon health, understand our personal risk, and take action before symptoms appear.
What Is Colorectal Cancer?
Colorectal cancer refers to cancers that develop in the colon or the rectum, which together make up the large intestine. Most colorectal cancers begin as small growths called polyps that form on the inner lining of the colon or rectum.
Polyps are not always cancerous, but certain types can slowly turn into cancer over time — a process that typically takes 10 or more years. Because polyps rarely cause symptoms in their early stages, regular screening is the most reliable way to detect them before they become cancerous. Removing a precancerous polyp during a colonoscopy can stop colorectal cancer before it ever starts.
What Are the Symptoms of Colorectal Cancer?
One of the most important things to understand about colorectal cancer is that it often causes no noticeable symptoms in the early stages. When symptoms do appear, they may include:
- Changes in bowel habits: persistent diarrhea, constipation, or narrowing of the stool that lasts more than a few days
- Blood in or on the stool: this may appear bright red or make the stool look dark brown or black
- Rectal bleeding: any unexplained bleeding from the rectum warrants a conversation with your doctor
- Abdominal discomfort: ongoing cramping, bloating, or pain in the belly area
- A feeling of incomplete emptying: the sensation that your bowel does not fully empty during a bowel movement
- Unexplained weight loss: losing weight without changes to diet or activity
- Persistent fatigue or weakness: low iron from slow internal bleeding can cause anemia and ongoing tiredness
What Does Colon Cancer Feel Like in the Beginning?
In the early stages, many people feel nothing at all. When early symptoms do occur, they are often subtle. Mild changes in bowel habits, occasional cramping, or low-level fatigue that is easy to attribute to stress, diet, or aging. This is one of the reasons colorectal cancer can go undetected for months or even years without routine screening.
The biggest red flag to watch for is any change that persists. A stomach bug that passes in a day or two is usually not cause for concern. But diarrhea, rectal bleeding, or abdominal pain that lingers for more than a few days without a clear explanation should prompt a visit to your doctor.
Are Symptoms Different in Women?
Colorectal cancer symptoms in women are largely the same as in men, but women may sometimes attribute symptoms like bloating, cramping, or changes in bowel habits to menstrual cycles, irritable bowel syndrome, or other conditions.
This can delay diagnosis. If you are a woman experiencing persistent digestive changes, do not dismiss them, bring them up with your provider.
Who Is at Risk for Colorectal Cancer?
Colorectal cancer can develop in anyone, but certain factors increase your risk. Some of these are within your control; others are not.
Risk Factors You Cannot Change
- Age: Risk increases significantly after age 45, though rising rates in young adults mean no age group is completely exempt.
- Family history: Having a close biological relative who had colorectal cancer or colon polyps raises your risk, particularly if they were diagnosed before age 45.
- Inherited conditions: Lynch syndrome and familial adenomatous polyposis (FAP) are genetic conditions that substantially increase colorectal cancer risk. If either runs in your family, talk to your doctor about early and more frequent screening.
- Personal history: If you have previously had colorectal cancer or certain types of polyps, your risk of recurrence is higher.
- Inflammatory bowel disease: Long-standing conditions such as Crohn’s disease or ulcerative colitis increase the risk due to chronic inflammation in the colon.
- Race and ethnicity: Black Americans and American Indian/Alaska Native populations have higher rates of colorectal cancer and tend to be diagnosed at later stages.
Risk Factors You Can Change
- Diet: A diet high in red and processed meats and low in fiber, fruits, and vegetables is associated with increased risk.
- Physical inactivity: A sedentary lifestyle is linked to higher colorectal cancer rates.
- Obesity: Excess body weight increases risk and is associated with worse outcomes.
- Smoking: Long-term tobacco use raises colorectal cancer risk.
- Alcohol use: Even moderate alcohol consumption has been associated with increased risk.
Experts estimate that more than half of colorectal cancer cases in the United States may be linked to these modifiable lifestyle factors– meaning prevention is within reach for many people.
Colorectal Cancer in Young Adults: A Growing Concern
While colorectal cancer has historically been thought of as a disease of older adults, rates among people under 50 have been rising steadily– by nearly 3% per year. Today, 1 in 5 people diagnosed with colorectal cancer in the United States is under age 55, and it is now the leading cause of cancer-related death among young adults.
Experts are still researching the exact causes of early-onset colorectal cancer, but contributing factors likely include diet, obesity, low physical activity, and changes in gut microbiome health. What is clear is that young people should not assume they are too young to develop this disease and should not ignore symptoms.
Colorectal Cancer Screening: When and How
Screening is the single most powerful tool we have against colorectal cancer. Current guidelines recommend that adults at average risk begin regular screening at age 45. Those with increased risk due to family history, Lynch syndrome, inflammatory bowel disease, or a prior cancer diagnosis may need to start earlier and screen more frequently.
Common Screening Options
- Colonoscopy: The gold standard for colorectal cancer screening. A flexible, camera-equipped scope examines the entire colon and rectum. Precancerous polyps can be detected and removed during the same procedure. Recommended every 10 years for average-risk adults.
- Stool-based tests: At-home options such as the fecal immunochemical test (FIT) or stool DNA test (Cologuard) detect blood or abnormal DNA in the stool. These are less invasive but require follow-up colonoscopy if results are abnormal.
- Blood-based screening: In 2024, the FDA approved the first blood test for colorectal cancer screening. While promising, it does not replace colonoscopy for all patients.
Talk to your primary care provider about which screening option is right for you based on your personal risk factors, age, and health history. The best screening test is the one you will actually do.
How Often Should You Get a Colonoscopy?
For adults at average risk, a colonoscopy is recommended every 10 years starting at age 45. If polyps are found, your doctor may recommend a follow-up colonoscopy sooner, typically in 3 to 5 years depending on the number and type of polyps removed. Those with a higher risk profile may need annual or more frequent stool-based testing between colonoscopies.
How to Help Prevent Colorectal Cancer
While there is no guaranteed way to prevent colorectal cancer, the following lifestyle habits can meaningfully lower your risk:
- Eat more fiber. Fruits, vegetables, whole grains, and legumes support colon health and are associated with reduced colorectal cancer risk.
- Limit red and processed meats. Reducing consumption of bacon, hot dogs, deli meats, and red meat lowers exposure to compounds linked to colorectal cancer.
- Stay active. Aim for at least 30 minutes of moderate physical activity most days of the week.
- Maintain a healthy weight. Obesity is a significant risk factor — even modest weight loss can reduce risk.
- Limit or avoid alcohol. If you drink, moderation matters.
- Quit smoking. Your provider can connect you with resources to help.
- Get screened on schedule. Prevention through polyp removal during colonoscopy is one of the most direct ways to reduce risk.
Colorectal Cancer Care at Valleywise Health
At Valleywise Health, our gastroenterology and hepatology team provides comprehensive colorectal cancer screening, diagnosis, and care for patients across Phoenix. Whether you are due for your first colonoscopy, experiencing symptoms you want evaluated, or managing a diagnosis, our specialists are here to guide you with compassionate, expert care.
Schedule an appointment to take the next step in protecting your colon health. Early detection saves lives and it starts with a conversation.
