For years, the advice was to start colorectal cancer screening at 50. That changed. National guidelines now recommend that most adults start at 45. If you just had a birthday, or your doctor brought it up at a checkup, you may have questions. This guide answers the common ones in plain words, for patients across Los Angeles and beyond.
Why does screening start at 45 now?
Colorectal cancer is cancer of the colon (large intestine) or rectum. Most of these cancers start as polyps, small growths on the inner lining of the colon. Polyps usually cause no symptoms. Some slowly turn into cancer over many years. Screening finds polyps and early cancers before they cause problems, and removing polyps can prevent cancer from forming at all.
Overall, colorectal cancer has become less common in older adults since the 1980s, largely because more people get screened. But the opposite is happening in younger adults. According to the American Cancer Society, rates in people younger than 50 rose by about 2.9% per year from 2013 to 2022. Researchers are still studying why. Diet, weight, activity and other factors may play a part, but many younger people who get colorectal cancer have none of the usual risk factors.
Because of this rise, the American Cancer Society lowered its starting age to 45 in 2018, and the U.S. Preventive Services Task Force (USPSTF), an independent panel of experts that reviews the evidence on screening, did the same in 2021. Today, screening is recommended for adults at average risk from 45 through 75. Between 76 and 85, the decision depends on your health and past screening.
The short version: if you are 45 or older and have never been screened, now is a good time. The best test is the one you will actually complete, and any positive result needs a follow-up colonoscopy.
Which screening test is right for you?
There are two main kinds of screening tests. Stool tests look for signs of cancer in a sample you collect at home. Visual exams look directly at the inside of the colon. Guidelines accept several options:
| Test | What it is | How often (if normal) |
|---|---|---|
| FIT (fecal immunochemical test) | A home stool test that checks for hidden blood | Every year |
| Stool DNA test (such as Cologuard) | A home stool test that checks for blood and abnormal DNA | Every 1 to 3 years |
| Colonoscopy | A doctor looks at the whole colon with a thin, flexible camera while you are sedated | Every 10 years |
| CT colonography | A CT scan of the colon, sometimes called a virtual colonoscopy | Every 5 years |
Stool tests
Stool tests are simple and private. You collect a small sample at home and mail it or drop it off. There is no prep and no time off work. The trade-off is that they must be repeated on schedule, and they are less likely than a colonoscopy to find polyps. A stool test is a good choice for many people at average risk who have no symptoms.
Colonoscopy
A colonoscopy lets the doctor see the entire colon and remove most polyps during the same exam. Tissue samples (biopsies) can be taken if something looks unusual. If the exam is normal and you are at average risk, you usually do not need another one for 10 years. The trade-offs are the bowel prep the day before, sedation (medicine that makes you relaxed and sleepy), and needing an adult to drive you home.
Newer blood tests for colorectal cancer screening are also available. They are easy, but they miss more early cancers and most precancerous polyps than the tests above, so medical groups do not see them as a replacement for a stool test or colonoscopy. Your plan depends on your health; Dr. Pimienta will talk with you about what fits you.
What does a positive stool test mean?
Getting a "positive" or "abnormal" stool test result can be frightening. It helps to know what it does and does not mean.
- It is not a cancer diagnosis. Most people with a positive stool test do not have cancer. Blood in the stool can come from polyps, hemorrhoids (swollen veins near the anus) or other causes.
- It does mean you need a colonoscopy. A positive stool test is only the first half of screening. The colonoscopy finds the cause and removes polyps if there are any.
- Do not repeat the stool test instead. A second negative stool test does not cancel out the first positive one.
- Do not wait months. Studies show that long delays between a positive stool test and colonoscopy are linked to worse outcomes. Aim to schedule soon.
The good news is that most follow-up colonoscopies find something treatable or nothing serious at all. You can read more about what polyps are and why they are removed on our colon polyps page.
What if colorectal cancer runs in my family?
Family history matters. If a parent, brother, sister or child (a first-degree relative) had colorectal cancer or an advanced polyp, your risk is higher, and the plan usually changes:
- Screening often starts at 40, or 10 years before the age your relative was diagnosed, whichever comes first.
- Colonoscopy is usually the recommended test, rather than a stool test.
- The exam is often repeated every 5 years instead of every 10.
Some families carry inherited conditions, such as Lynch syndrome, that raise the risk even more. Several relatives with colon, uterine or other cancers, especially at young ages, is a reason to tell your doctor. Inflammatory bowel disease (Crohn's disease or ulcerative colitis) also changes the schedule.
Many families do not talk about cancer or "stomach problems" at the dinner table, and older relatives may not know the exact diagnosis. It is worth asking anyway. A short conversation with a parent, aunt or older cousin can change when and how you should be screened. Bring what you learn to your visit, even if it is incomplete.
Screening versus symptoms: when not to wait
Screening is for people who feel fine. If you have symptoms, you need an evaluation, whatever your age. See a doctor if you notice:
- Blood in or on your stool, or dark, tar-like stools (see our rectal bleeding page)
- A change in bowel habits that lasts more than a few weeks
- Belly pain that does not go away
- Weight loss you cannot explain
- Iron-deficiency anemia (low iron in your blood) found on a blood test
Younger adults are more likely to brush off these signs, and so are their doctors. If something feels wrong, ask to be checked.
Call 911 or go to the nearest emergency room if you have heavy rectal bleeding, black or bloody stools with dizziness or fainting, vomiting blood, or severe or worsening abdominal pain.
How does Medicare cover colorectal cancer screening?
Most people join Medicare at 65, well past the starting age for screening, so many Medicare patients are due for a repeat test rather than a first one. According to Medicare.gov, Part B covers screening colonoscopy once every 10 years for people at average risk, or every 2 years for people at high risk. If your doctor accepts assignment, you pay nothing for the screening test itself.
Two details are worth knowing:
- After a positive stool test, Medicare now covers the follow-up colonoscopy as a screening test, so it is treated like the rest of screening.
- If a polyp is removed, you may owe a coinsurance share for the doctor and the facility. Medicare.gov lists the current percentage.
Dr. Pimienta accepts Medicare, including patients with a secondary (supplemental) plan. If you have a Medicare Advantage plan, call the office before booking so the team can check your plan. If you have other insurance, the practice is out of network and visits are self-pay; the team explains pricing and how out-of-network benefits may work before anything is booked. Our insurance and payment page has the details.
How to get started in Los Angeles
Starting is simpler than many people expect. A typical path looks like this:
Request a visit
Use the online form or call the office. Visits are in person at the Wilshire Boulevard office in Mid-City West, or by secure video for patients who are in California at the time of the visit.
Talk through your history
Dr. Pimienta asks about your symptoms, your family history and any past tests, then helps you choose a screening plan. He believes good care begins with listening, and that includes your worries about the prep or the procedure.
Get screened
If a colonoscopy is the right choice, it is done at Specialty Surgical Center of Beverly Hills, less than a mile west of the office on Wilshire Boulevard. You will get written prep instructions. Our day-by-day prep guide walks through the process.
Review your results
You will learn what was found, whether any polyps were removed, and when your next screening is due.
Dr. Pimienta sees adults from across Los Angeles County, in English and Spanish. For many Spanish-speaking families, being able to ask questions in their own language makes the whole process less stressful. Relatives are welcome to help with scheduling and to join the conversation.
When to see a GI doctor
Consider seeing a gastroenterologist (a doctor who specializes in the digestive system) if you are 45 or older and have never been screened, if you had a positive stool test, if you have a family history of colorectal cancer or polyps, or if you have any of the symptoms above. You can learn more on our colorectal cancer screening and surveillance page, or request an appointment and the team will call you back.
References
- U.S. Preventive Services Task Force. Colorectal Cancer: Screening. 2021.
- American Cancer Society. Guideline for Colorectal Cancer Screening.
- American Cancer Society. Key Statistics for Colorectal Cancer.
- Medicare.gov. Colonoscopies (screening).
- American College of Gastroenterology. Colorectal Cancer.