The recent deaths of actor James Van Der Beek and beloved actress Catherine O’Hara have brought colorectal cancer back into the national spotlight, sparking renewed conversations about screening, early detection, and the alarming rise of this disease in younger adults. Van Der Beek, who publicly shared his battle with colorectal cancer, and O’Hara, who died from complications of the disease, represent a troubling trend in colorectal cancer news that has medical professionals urging adults to take screening recommendations seriously, even if they’re younger than previously thought necessary.

Mayla Chung, a certified physician assistant specializing in gastroenterology at Tryon Medical Partners, sees patients navigating colorectal cancer concerns daily. Her work focuses on screening, early detection, and helping patients understand when symptoms warrant immediate evaluation versus routine monitoring.

What is colorectal cancer? Understanding colon cancer, rectal cancer, and related terms

Colorectal cancer refers to cancer that develops in either the colon or rectum, which together form the large intestine: the final portion of the digestive tract. Understanding the terminology helps clarify what doctors mean when discussing screening, diagnosis, and treatment.

• Colon cancer specifically affects the colon, which makes up the majority of the large intestine. This is where the body absorbs water and nutrients from digested food and forms waste for elimination. 
• Rectal cancer develops in the rectum, the final several inches of the large intestine that connects the colon to the anus. While anatomically distinct from the colon, the rectum functions as part of the same organ system, and similar cellular changes can lead to cancer in both locations.
• Colorectal cancer serves as an umbrella term encompassing both colon and rectal cancers. Medical professionals use this combined terminology because the two cancers share risk factors, screening methods, and often similar treatment approaches. When doctors recommend colorectal cancer screening, they’re looking for abnormalities throughout the entire colon and rectum. 

The screening process typically involves a colonoscopy, during which gastroenterologists examine the entire length of the colon and rectum, looking for polyps, small growths that can develop into cancer if left untreated. 

“Detecting and removing these precancerous polyps during screening can help prevent colon cancer from developing in the first place, making colonoscopy both a diagnostic and preventive procedure,” PA-C Chung explains.

At what age should you get a colonoscopy? Current colon cancer testing recommendations

Colonoscopy screening guidelines have evolved significantly in recent years, with recommended starting ages lowering in response to rising colorectal cancer rates in younger populations. Understanding when you should begin screening (and how family history affects that timeline) is crucial for early detection.

• Standard screening age: For adults without specific risk factors, colorectal cancer screening now begins at age 45. This represents a recent change from the previous recommendation of age 50, reflecting growing concern about early-onset colorectal cancer in people in their 40s. This shift means many people who thought they had several more years before needing a colonoscopy should actually schedule screening now.
• Family history considerations: If you have a first-degree relative (parent or sibling) diagnosed with colon cancer before age 60 according to ACG guidelines, or if there are two or more first-degree relatives at any age diagnosed with colon cancer, your screening timeline accelerates significantly. You should begin screening either 10 years before the age at which that family member was diagnosed, or at age 40, whichever comes first. For example, if your mother was diagnosed with colon cancer at age 52, you should have your first colonoscopy at age 42 (age 40 instead of 42 since that comes earlier). If your father was diagnosed at age 38, you should begin screening at age 28 (10 years earlier) rather than waiting until age 40.
• Symptom-based screening: Age recommendations become irrelevant when symptoms develop. Certain warning signs warrant immediate colonoscopy regardless of age or family history. Rectal bleeding, significant changes in bowel habits, unexplained weight loss, or persistent abdominal pain all justify screening, even in young adults. 

“A 20-year-old experiencing persistent rectal bleeding should discuss with a professional about the risks, benefits, and alternatives of undergoing a colonoscopy,” PA-C Chung emphasizes.

• Screening intervals: After your initial colonoscopy, the timing of follow-up screenings depends on what the gastroenterologist finds. If no precancerous polyps are detected and you have no family history, you typically won’t need another colonoscopy for 10 years. However, if polyps are found, the number, size, and type determine your next screening date, which could be anywhere from 1 to 10 years, depending on these factors.

Why is colon cancer rising in young people? Understanding the trend

The increase in colorectal cancer among adults under 50 represents one of the most concerning trends in oncology today. While researchers continue investigating the causes, several factors likely contribute to this troubling pattern.

• Dietary factors: Diet appears to play a significant role in early-onset colorectal cancer. High consumption of red and processed meats has been linked to increased colorectal cancer risk across multiple studies. Modern diets often include significantly more processed foods, added sugars, and ultra-processed ingredients than previous generations consumed. These dietary patterns may create inflammatory conditions in the digestive tract that promote cancer development over time.
• Environmental exposures: Emerging research suggests environmental factors, including microplastics, may contribute to rising cancer rates. Microplastics have become ubiquitous in food, water, and air, and preliminary studies indicate they can cause inflammation and cellular changes in digestive tissues. While definitive proof remains elusive, the timeline of microplastic proliferation roughly correlates with increasing early-onset colorectal cancer rates.
• Improved detection: Part of the apparent increase may reflect better and more frequent detection rather than purely rising incidence. As awareness grows and more young adults undergo colonoscopy for symptoms, previously undiagnosed cases are being identified. The recent lowering of screening age to 45 will likely identify additional cases that would have gone undetected under previous guidelines.
• Gut microbiome disruption: Changes in the gut microbiome (the complex community of bacteria and other microorganisms in the digestive tract) may influence colorectal cancer risk. Antibiotic overuse, dietary changes, and environmental factors can all disrupt the healthy balance of gut bacteria, potentially creating conditions that favor cancer development. 

“Despite intensive research, definitive answers remain frustratingly incomplete. Scientists understand some risk factors, but cannot fully explain why colorectal cancer is rising so dramatically in younger adults. This uncertainty makes following screening guidelines and paying attention to symptoms even more critical, as prevention and early detection remain the most effective tools available,” PA-C Chung cautions.

How fast does colon cancer grow? Understanding polyps and cancer development

The timeline of colorectal cancer development varies significantly depending on multiple factors, making it impossible to provide a single answer about growth rate. Understanding the progression from normal tissue to precancerous polyps to cancer helps explain why regular screening matters so much.

• What are polyps? Polyps are growths that develop on the inner lining of the colon or rectum. They vary in size from tiny bumps barely visible during colonoscopy to large masses several centimeters across. Most polyps cause no symptoms, which is why screening colonoscopy is essential for detection. One of the more effective modalities is through direct visualization during colonoscopy in which gastroenterologists can identify these growths before they cause problems.
• Polyp development timeline: Precancerous polyps typically take years to develop and grow. A small polyp might exist for several years before becoming large enough to pose a cancer risk. This slow growth provides a crucial window for detection and removal during colonoscopy. 
• Precancerous polyps explained: Not all polyps are precancerous, but certain types have the potential to develop into cancer if left untreated. The specific type of polyp cannot be determined by appearance alone; tissue must be removed and examined under a microscope by a pathologist. This is why gastroenterologists remove polyps during colonoscopy, even when they appear benign; the only way to know whether a polyp is precancerous is through laboratory analysis.
• What causes polyps? The exact cause of polyp formation remains incompletely understood. Genetic factors clearly play a role, as polyps run in families and certain genetic syndromes dramatically increase polyp development. Beyond genetics, the specific triggers that cause cells to begin forming polyps aren’t fully known, though diet, inflammation, and other factors likely contribute.
• How many polyps are normal? There is no specific number of polyps considered “normal” during colonoscopy. Some people have no polyps, while others have several or many. The number of polyps found, along with their size and type, helps determine when you need your next colonoscopy. Someone with no polyps and no family history typically waits 10 years for the next screening. Someone with multiple polyps might need a colonoscopy again in 1 to 10  years. Your gastroenterologist individualizes this recommendation based on your specific findings, age, and family history.
• Cancer growth and staging: Once cancer develops, the growth rate depends on the cancer’s stage and biological characteristics. Some colorectal cancers grow relatively slowly over months or years, while others progress more rapidly. This variability makes it impossible to predict exactly how fast any individual’s cancer will advance, which is why prompt evaluation of symptoms and adherence to screening guidelines are critical.

When should you seek medical attention? Recognizing warning signs

Understanding which symptoms warrant immediate medical evaluation versus routine monitoring can be challenging, but certain warning signs should never be ignored, regardless of your age.

Red flag symptoms requiring prompt evaluation:

• Rectal bleeding: Any bleeding from the rectum deserves medical attention, even if you suspect hemorrhoids. While hemorrhoids are common and often the explanation for minor bleeding, they cannot be assumed to be the cause without proper evaluation. Bleeding can also indicate polyps, inflammatory bowel disease, or cancer. The color and amount of blood provide some clues; bright red blood typically suggests bleeding near the rectum, while dark or black stools suggest bleeding higher in the digestive tract, but only medical evaluation can determine the source.
• Unintentional weight loss: Losing weight without trying, particularly if accompanied by other digestive symptoms, warrants urgent evaluation. Cancer and other serious conditions can cause weight loss by affecting appetite, nutrient absorption, or overall metabolism. If you’ve lost 10 pounds or more without dietary changes or increased exercise, schedule an appointment with your primary care clinician or gastroenterologist.
• Changes in bowel habits: Persistent changes in your normal bowel pattern, such as new constipation, diarrhea, or alternating between the two, can indicate various conditions, including colorectal cancer, inflammatory bowel disease, or other digestive disorders. Occasional changes related to diet or stress can be normal, 
• Abdominal pain: While occasional abdominal discomfort is common, persistent or severe pain, particularly if localized to one area or accompanied by other symptoms, should be evaluated. Colorectal cancer can cause cramping, bloating, or pain, though these symptoms are nonspecific and have many potential causes.

“If you’re experiencing warning signs, don’t assume you’re too young for it to be something serious. Don’t rely on internet searches or social media for diagnosis. Schedule an appointment with a qualified healthcare clinician who can properly evaluate your symptoms and determine whether a colonoscopy or other testing is warranted,” PA-C Chung advises. 

The bottom line on colorectal cancer screening and awareness

Remember that colorectal cancer is highly preventable and treatable when caught early. Unlike many cancers, where screening only detects existing disease, colonoscopy can prevent colorectal cancer by identifying and removing precancerous polyps before they become malignant. This makes adherence to screening guidelines one of the most effective cancer prevention strategies available.

If you’re 45 or older and haven’t had a colonoscopy, schedule one. If you have a family history of colorectal cancer, don’t wait until age 45; talk to your doctor about when you should begin screening based on your specific family history. If you’re experiencing rectal bleeding, unexplained weight loss, or persistent changes in bowel habits, seek medical evaluation regardless of your age.

The rising incidence of colorectal cancer in younger adults makes these recommendations more urgent than ever. While researchers work to understand why this trend is occurring, the tools for prevention and early detection, colonoscopy, symptom awareness, and prompt medical evaluation, remain highly effective. Use them.

If you’re concerned about colorectal cancer risk or need to schedule screening, visit your primary care clinician for a referral to the Tryon Medical Partners gastroenterology specialty page if one is needed.