March is Colorectal Cancer Awareness Month, and I want to use this post to talk about something that doesn’t get nearly enough attention given how common and how preventable this cancer actually is.
Colorectal cancer is the third most common cancer diagnosed in the United States and the second leading cause of cancer death when men and women are combined. Those numbers are sobering. What makes them even more frustrating is that colorectal cancer is one of the most preventable and most treatable cancers we know of, when it’s caught early. The problem is that too many people aren’t getting screened, aren’t recognizing early symptoms, and aren’t aware that rates are rising sharply in adults under 50.
So let’s talk about it plainly.
The Rise in Younger Adults
For decades, colorectal cancer was considered a disease of older adults, which is why screening used to start at age 50. That’s no longer the picture. Rates of colorectal cancer in adults under 50 have been rising steadily for the past several decades, and the reasons aren’t entirely clear. Researchers point to a combination of factors: changes in diet and the gut microbiome, rising rates of obesity and sedentary behavior, increased processed food consumption, and possibly environmental exposures. Whatever the drivers, the trend is real and it matters.
In 2021, the US Preventive Services Task Force updated its recommendation and lowered the routine screening age from 50 to 45 for average-risk adults. If you’re 45 or older and haven’t been screened, that’s the first conversation to have. And if you have a family history or other risk factors, screening may need to start even earlier.
Symptoms People Ignore
One of the reasons colorectal cancer is so often caught late is that the early symptoms are easy to dismiss or attribute to something less serious. Here’s what to pay attention to:
- Blood in the stool or rectal bleeding. This is the one people most commonly explain away as hemorrhoids. Sometimes it is. But blood in the stool should always be evaluated, not assumed. Don’t let it go unchecked.
- A change in bowel habits that lasts more than a few weeks. This includes persistent diarrhea, constipation, or a change in the consistency or caliber of your stool. Narrow stools in particular can be a sign of something obstructing the colon.
- Feeling like your bowel doesn’t fully empty. That persistent sense of needing to go even after you just did is worth mentioning to your provider.
- Unexplained abdominal cramping, gas, or pain. Occasional bloating is normal. Persistent, unexplained abdominal discomfort is not something to sit on.
- Unexplained fatigue or weakness. Colorectal tumors can cause slow, chronic blood loss that leads to iron deficiency anemia, which shows up as persistent tiredness and weakness even when nothing else seems wrong.
- Unintentional weight loss. Losing weight without trying to is always a reason to get evaluated.
None of these symptoms automatically mean cancer. Most of the time they don’t. But they deserve attention, not dismissal, and that’s especially true if they persist or combine with each other.
If you’re seeing blood in your stool and assuming it’s hemorrhoids, please get it checked. Hemorrhoids are common and usually benign, but they’re also one of the most common reasons people delay getting evaluated for something more serious. The evaluation is simple. The peace of mind is worth it.
Risk Factors: Know Where You Stand
Some risk factors for colorectal cancer are things you can’t change. Others are things you have real influence over. It’s worth knowing both.
Family History and Genetics
Having a first-degree relative, meaning a parent, sibling, or child, who had colorectal cancer or certain types of polyps significantly increases your risk. If that applies to you, current guidelines generally recommend starting screening at age 40, or ten years before the age at which your relative was diagnosed, whichever comes first.
There are also inherited genetic syndromes that dramatically elevate colorectal cancer risk. The two most important are Lynch syndrome (also called hereditary nonpolyposis colorectal cancer, or HNPCC) and familial adenomatous polyposis (FAP). Lynch syndrome is the most common hereditary colorectal cancer syndrome and accounts for roughly 3% of all colorectal cancers. People with Lynch syndrome often need to begin colonoscopy surveillance in their 20s or early 30s and repeat it every one to two years. FAP causes hundreds to thousands of polyps to develop in the colon and rectum, often in adolescence, and without intervention essentially always leads to cancer.
If you have a strong family history of colorectal cancer or polyps, especially at younger ages or across multiple generations, it’s worth asking about genetic testing. Identifying a hereditary syndrome doesn’t just affect your own screening plan. It has implications for your children and siblings as well.
Personal History
If you’ve had colorectal polyps before, your risk of developing more is higher than average and your follow-up colonoscopy schedule will be more frequent than the standard ten-year interval. The same applies if you have a personal history of inflammatory bowel disease, including Crohn’s disease or ulcerative colitis. Long-standing IBD significantly increases colorectal cancer risk, and surveillance colonoscopies are an important part of managing that risk over time.
Diet and Lifestyle
The evidence here is substantial. A diet high in red and processed meat is consistently associated with increased colorectal cancer risk. Processed meats in particular, things like bacon, hot dogs, deli meat, and sausage, are classified as Group 1 carcinogens by the World Health Organization, meaning the evidence that they cause cancer is strong. Red meat is classified as Group 2A, meaning it probably does. This doesn’t mean one burger causes cancer, but it does mean that regular, high consumption of these foods meaningfully increases risk over time.
On the protective side, a diet high in fiber, particularly from vegetables, fruits, legumes, and whole grains, is associated with lower colorectal cancer risk. Fiber feeds beneficial gut bacteria, supports healthy bowel transit, and may reduce the time that potential carcinogens spend in contact with the colon lining. Physical activity also reduces risk, independent of weight. Obesity, especially abdominal obesity, is an independent risk factor. Smoking increases risk. Heavy alcohol use increases risk.
These aren’t abstract statistics. They’re modifiable factors, which means there’s real leverage here for most people.
Screening Options: You Have More Choices Than You Think
A lot of people put off colorectal cancer screening because they’re dreading a colonoscopy. And while colonoscopy is the gold standard, it’s not the only option. Here’s an honest look at what’s available.
Colonoscopy
This is the most comprehensive screening tool. A gastroenterologist uses a flexible camera to examine the entire colon and rectum, and can remove polyps on the spot during the same procedure. It requires bowel prep the day before (not fun, but manageable), sedation on the day of, and someone to drive you home. If the results are normal and you’re average risk, you typically don’t need another one for ten years. The biggest advantage is that it’s both diagnostic and therapeutic. If a polyp is found, it’s removed before it has a chance to become cancer.
Stool-Based Tests
For people who want a non-invasive option, stool-based tests are a legitimate alternative for average-risk individuals. The main options are:
- FIT (Fecal Immunochemical Test): Detects blood in the stool that isn’t visible to the naked eye. Done at home, no dietary restrictions, no prep. Done annually.
- Cologuard (stool DNA test): Detects both blood and abnormal DNA shed by polyps or cancer cells. Also done at home. Done every three years. More sensitive than FIT but also has a higher false-positive rate, meaning it sometimes flags something that turns out not to be there.
- gFOBT (guaiac-based fecal occult blood test): An older, less specific stool blood test. Requires dietary restrictions before collection. Done annually. Less commonly used now that FIT is available.
The important thing to know about stool-based tests is that a positive result requires follow-up with a colonoscopy. They’re a first step, not a final answer.
CT Colonography (Virtual Colonoscopy)
A CT scan of the abdomen and pelvis that produces detailed images of the colon. Still requires bowel prep but no sedation. Done every five years for average-risk individuals. If something is found, a standard colonoscopy is needed for removal. Not universally covered by insurance, which is worth checking in advance.
The best screening test is the one you’ll actually do. If the idea of a colonoscopy has been keeping you from getting screened at all, a stool-based test is a real and reasonable starting point. Something is always better than nothing. Let’s talk about what makes the most sense for you.
Why Early Detection Changes Everything
When colorectal cancer is caught at a localized stage, before it has spread beyond the colon or rectum, the five-year survival rate is over 90%. When it’s caught after it has spread to distant organs, that number drops to around 15%. That gap is enormous, and it’s almost entirely explained by whether or not people got screened.
Screening doesn’t just catch cancer early. In many cases it prevents cancer from developing at all, because polyps, which are the precancerous growths that colorectal cancer usually develops from, can be removed during a colonoscopy before they ever become malignant. That’s a genuinely remarkable thing. We have a tool that can find and remove the precursor to a cancer before it starts, and a significant portion of people who are eligible for it aren’t using it.
If you’re 45 or older and haven’t been screened, this is the nudge. If you have a family history or symptoms you’ve been ignoring, don’t wait until you feel like something is really wrong. Colorectal cancer often doesn’t announce itself until it’s advanced. That’s exactly why screening exists.
This is the kind of conversation that’s easy to have in a DPC practice, where there’s time to actually go through your history, talk through your options, and make a plan that fits your situation. If you have questions or you’re not sure where to start, reach out.
Daniel Corbin, DNP, APRN, FNP-C
Board-certified Family Nurse Practitioner and founder of Staywell Health, a direct primary care practice in Raleigh, NC specializing in whole-person care, LGBTQ+ health, and lifestyle medicine.