Colorectal cancer is the second leading cause of cancer death in the United States, and adults over 65 face more than double the incidence rate of younger adults. The good news is that this is one of the most preventable and treatable cancers we know of — when it is caught early. The bad news is that roughly one in three eligible Americans has never been screened at all.
If you are a senior who has been putting off screening, or if you simply do not know where to start, this guide walks you through every step — from the warning signs you should never ignore, to the types of tests available (including a groundbreaking new blood test), what to expect during a colonoscopy, how insurance and Medicare cover the costs, and what happens if polyps or cancer are found.
Warning Signs Every Senior Should Watch For
Colorectal cancer is often called a “silent” disease because polyps and early-stage tumors frequently produce no symptoms at all. That is exactly why routine screening matters so much. However, there are warning signs that should prompt an immediate conversation with your doctor:
Changes in bowel habits. Persistent diarrhea, constipation, or a noticeable change in the consistency of your stool lasting more than a week or two is worth investigating. Many seniors chalk this up to diet or aging, but a lasting change can be an early signal.
Blood in the stool. This may appear as bright red streaks, dark clots, or black, tarry-looking stools. Blood on the toilet paper after wiping also counts. Do not assume it is hemorrhoids without having it checked.
Unexplained abdominal pain or cramping. Ongoing discomfort, bloating, or a persistent feeling that your bowel does not empty completely can indicate a polyp or mass in the colon.
Unexplained weight loss or fatigue. If your diet and activity level have not changed but the pounds are dropping or your energy has plummeted, this can signal internal blood loss or a tumor affecting your metabolism.
Iron-deficiency anemia. Chronic, slow bleeding from a colon polyp can deplete your iron over time. If routine bloodwork shows low iron or anemia without an obvious explanation, colorectal screening is warranted.
A key point for seniors specifically: Many older adults live with chronic conditions such as diabetes, heart disease, or kidney problems. These conditions can mask or overlap with digestive symptoms. If something feels different from your baseline, do not dismiss it. A quick conversation with your doctor, or even a simple stool test, can provide peace of mind or catch a problem early.
The Screening Tests Available to You
There are several types of colorectal screening, and the right one for you depends on your risk level, your health, and your preferences.
Stool-Based Tests (At-Home Options)
Fecal Immunochemical Test (FIT) — This is a simple at-home test you do annually. You collect a small stool sample using a kit provided by your doctor, place it in a tube, and mail it to a lab. No dietary changes or bowel prep are needed. The lab checks for hidden blood in the stool, which can indicate polyps or cancer.
Stool DNA Tests (Cologuard, ColoSense) — These at-home kits test for both blood and DNA markers associated with colorectal cancer. You collect a stool sample, ship it to the lab, and wait for results. The test is repeated every one to three years depending on the brand. No laxative prep or dietary changes are needed.
These stool-based tests are a good option for people at average risk who want a non-invasive starting point. However, if any stool-based test comes back positive, a follow-up colonoscopy will be required.
The New Blood Test — Shield by Guardant Health
This is the option getting the most attention right now, and for good reason.
Shield is the first and only blood test to receive full FDA approval as a primary colorectal cancer screening option for average-risk adults aged 45 and older. It was approved in 2024, and as of May 2026 the American Cancer Society has added it to its updated screening guidelines.
Here is what makes it significant: Shield requires nothing more than a standard blood draw during a routine doctor’s visit. No fasting, no bowel prep, no stool samples. Your doctor draws blood, sends it to a lab, and the test looks for cell-free tumor DNA circulating in your bloodstream. Results come back, and if the test is positive, you would then be referred for a colonoscopy to investigate further.
In clinical studies, Shield demonstrated approximately 83 to 84 percent sensitivity for detecting colorectal cancer with about 90 percent specificity. It should be repeated every three years.
There are a few important things to understand about Shield. It is designed for average-risk adults, meaning it is not intended for people who are already considered high-risk due to family history, genetic conditions like Lynch syndrome, or a personal history of inflammatory bowel disease. For those individuals, colonoscopy remains the recommended screening method. Shield is also less effective at detecting precancerous polyps compared to colonoscopy — it is strongest at catching actual cancer. Think of it as a powerful tool to catch people who might otherwise skip screening altogether, rather than a replacement for colonoscopy.
Shield is now available through Quest Diagnostics locations nationwide and has been the subject of a mobile screening tour visiting over 100 communities across the country.
Colonoscopy — The Gold Standard
A colonoscopy remains the most thorough and effective screening method. It allows a gastroenterologist to visually examine the entire length of the colon and rectum, and — critically — to remove any polyps found during the procedure itself. This is both a screening tool and a prevention tool in one, because removing precancerous polyps eliminates the chance of those polyps ever becoming cancer.
For average-risk individuals, a colonoscopy is recommended every ten years starting at age 45. For high-risk individuals, your doctor may recommend starting earlier and repeating the procedure more frequently.
Other Options
Flexible Sigmoidoscopy — Similar to a colonoscopy but examines only the lower third of the colon. Less prep is involved, but it does not visualize the entire colon. Recommended every five years for those at average risk, or every ten years if combined with annual FIT testing.
CT Colonography (Virtual Colonoscopy) — A CT scan creates detailed images of the colon. Less invasive than a traditional colonoscopy, but if polyps are found you will still need a standard colonoscopy to remove them.
Preparing for Your Doctor’s Visit
Walking into a doctor’s appointment prepared makes all the difference. Here is what seniors should do before requesting colorectal screening:
Gather your family history. Write down any relatives who have had colorectal cancer, polyps, or related conditions like Lynch syndrome, familial adenomatous polyposis (FAP), or inflammatory bowel disease (Crohn’s disease or ulcerative colitis). Note how old they were at diagnosis. This information directly affects which screening your doctor will recommend and how often.
List your own medical history. Include any prior colonoscopies or screening results, any history of polyps (and whether they were described as adenomatous or hyperplastic), any digestive conditions, and any history of radiation to the abdomen or pelvis.
Write down your symptoms. If you have noticed any of the warning signs discussed above — changes in bowel habits, blood in the stool, unexplained weight loss, persistent pain or bloating — note when they started, how often they occur, and whether anything makes them better or worse.
List your current medications. Some medications, including blood thinners, aspirin, and iron supplements, can affect screening results or require adjustments before a colonoscopy.
Bring your questions. Good ones to ask include: Based on my risk level, which screening do you recommend? How often should I be screened? Is the new Shield blood test appropriate for me? If I need a colonoscopy, what is the prep process? Will my insurance cover this fully?
What to Expect If a Colonoscopy Is Required
For many seniors, the colonoscopy itself is the source of the most anxiety. Knowing what to expect takes a lot of that anxiety away.
Before the Procedure — The Prep
The bowel prep is the part most people dread, but it is essential for the doctor to get a clear view of the colon lining. Your doctor will provide specific instructions, but here is the general process:
Several days before the procedure, you may be asked to stop taking certain medications, especially blood thinners, iron supplements, and some anti-inflammatory drugs. Your doctor will give you specific guidance.
The day before the procedure, you will switch to a clear-liquid diet — broth, clear juices (no red or purple colors), gelatin, water, black coffee, and tea. No solid food.
You will drink a prescribed bowel-prep solution, which is a large-volume liquid laxative. Some preps are split into two doses — half the evening before and half the morning of the procedure — which many patients find easier to tolerate. The goal is to completely empty the colon. Expect to spend significant time in the bathroom. Stay near one and stay hydrated.
The Day of the Procedure
You will check in at an outpatient endoscopy center or hospital. An IV will be placed, and you will receive sedation — typically a medication called propofol or a combination of a sedative and pain reliever. Most patients are in a comfortable twilight state and remember little or nothing of the procedure.
The gastroenterologist will insert a thin, flexible tube with a camera (a colonoscope) through the rectum and guide it through the entire colon. The procedure itself usually takes 20 to 40 minutes. If polyps are found, they are removed during the procedure using small instruments passed through the scope. Tissue samples (biopsies) may also be taken and sent to a pathology lab.
After the Procedure
You will spend 30 to 60 minutes in a recovery area as the sedation wears off. You may feel bloated or gassy as air used to inflate the colon during the procedure works its way out. This is normal and temporary.
Because you received sedation, you will not be able to drive yourself home. Arrange for someone to pick you up in advance — this is mandatory and the facility will not release you without a ride.
Your doctor will typically discuss preliminary findings with you before you leave. If polyps were removed, pathology results usually come back within one to two weeks.
What Insurance Covers for Seniors
Medicare Coverage
Medicare Part B covers several colorectal cancer screening options at no cost to you when the test is considered preventive (meaning you have no symptoms and are not being tested because of a specific complaint):
- Fecal Occult Blood Test (FOBT) or FIT — covered once every 12 months for beneficiaries age 50 and older, with no deductible and no coinsurance.
- Screening colonoscopy — covered once every 10 years for average-risk beneficiaries, or once every 2 years for high-risk beneficiaries. No deductible and no coinsurance when done by a participating provider.
- Flexible sigmoidoscopy — covered once every 4 years for beneficiaries age 50 and older.
- Stool DNA test (Cologuard) — covered once every 3 years for beneficiaries who meet certain criteria.
- Blood-based biomarker screening (Shield) — Medicare Part B now covers this for beneficiaries aged 45 to 85 who show no symptoms of colorectal disease. If the blood test comes back positive, Medicare also covers the follow-up colonoscopy as a screening test.
An important cost distinction: If your colonoscopy is classified as a preventive screening, Medicare covers it at 100 percent with no out-of-pocket cost. However, if polyps are found and removed during the procedure, there has historically been a gray area where the procedure could be reclassified as “diagnostic” or “therapeutic,” potentially triggering coinsurance charges. Legislation has been working to close this gap, but it is still wise to confirm with your provider and Medicare plan before the procedure. Ask specifically: “If polyps are found and removed during my screening colonoscopy, will I owe anything?”
Medicare Advantage Plans
Medicare Advantage plans are required to cover at least the same preventive screenings as Original Medicare. However, network restrictions and prior authorization requirements may apply. Check with your specific plan.
Private Insurance and the Affordable Care Act
Under the ACA, private insurers are required to cover all colorectal cancer screening tests recommended by the U.S. Preventive Services Task Force with no out-of-pocket costs — no copays, no deductibles, no coinsurance. This applies to adults aged 45 to 75 at average risk.
No-Cost and Low-Cost Options for the Uninsured or Underinsured
If you lack insurance or face financial hardship, several programs can help:
- Colorectal Cancer Alliance Screening Support Program — Call their toll-free helpline at (877) 422-2030. They offer screening resources, financial assistance, and referrals to free or low-cost screening services.
- ColonoscopyAssist — This program provides an all-inclusive discounted rate for out-of-pocket colonoscopy patients. No income, residency, or immigration limitations apply. They also offer cash stipends toward the cost and interest-free payment plans.
- Blue Hope Financial Assistance Fund — Offers low-cost colonoscopies and FIT tests, plus $300 stipends for screening assistance or $200 toward treatment costs for eligible individuals (uninsured or underinsured with household income below $75,000).
- Federally Qualified Health Centers (FQHCs) — Community health centers across the country provide care on a sliding-fee scale based on income. Many offer colorectal screening referrals and can connect you with free or reduced-cost colonoscopy programs.
- State Cancer Screening Programs — Many state departments of health offer free screenings, including colonoscopies, for qualifying residents. Contact your state health department to ask what is available.
- Hill-Burton Facilities — Hospitals and health systems that received Hill-Burton funding are required to provide free or reduced-cost care to patients with limited income, even if the service is not covered by Medicare or Medicaid.
What Happens If Cancerous Polyps Are Found
This is the question that keeps people up at night, and understandably so. But it helps to understand the full range of outcomes, because the news is very often good.
Understanding Polyps
Not all polyps are dangerous. Most polyps found during a colonoscopy are benign. The types that matter most are adenomatous polyps (adenomas) and sessile serrated polyps, which are considered precancerous — meaning they have the potential to develop into cancer over time if left in place, but they are not cancer yet.
When polyps are removed during a colonoscopy, they are sent to a pathology lab for examination. The pathologist determines the type, size, and whether any cancerous cells are present. This is where the distinction between precancerous and cancerous becomes critical.
Best-Case Scenario
The most common best-case outcome is that polyps are found, removed completely during the colonoscopy, and pathology shows they are benign or precancerous with no cancerous cells present. In this case, you have essentially had cancer prevention — the polyps were caught and eliminated before they ever had the chance to become dangerous. Your doctor will schedule a follow-up colonoscopy in three to five years (rather than the standard ten) to monitor for new growth, and you go on with your life.
Even if a polyp contains cancerous cells, the best-case scenario is that the cancer is confined entirely within the polyp itself and has not invaded the stalk or the wall of the colon. This is classified as Stage 0 (carcinoma in situ) or very early Stage I. In many of these cases, the complete removal of the polyp during the colonoscopy is the only treatment needed. The five-year survival rate for localized colorectal cancer — meaning it has not spread beyond the colon wall — is approximately 91 percent.
Worst-Case Scenario
The worst-case scenario is that pathology reveals the polyp contained invasive cancer that has penetrated the wall of the colon, or that additional imaging reveals the cancer has already spread to nearby lymph nodes or to distant organs such as the liver or lungs (metastatic disease, Stage IV).
In this situation, treatment typically involves surgery to remove the affected section of the colon (a partial colectomy), followed by chemotherapy and possibly radiation therapy. Stage IV colorectal cancer has a five-year survival rate of roughly 15 percent, though outcomes vary depending on the specific location and extent of spread, the patient’s overall health, and how the cancer responds to treatment. New targeted therapies and immunotherapies have been improving these numbers in recent years.
What Happens If Colorectal Cancer Is Not Treated?
Untreated colorectal cancer will continue to grow. A polyp that is precancerous today can become a localized cancer within several years, and that localized cancer can eventually invade deeper into the colon wall, spread to nearby lymph nodes, and ultimately metastasize to distant organs.
The progression from polyp to cancer is usually slow — often taking 10 to 15 years — which is precisely why regular screening is so effective. But once cancer has developed and begins to spread, the trajectory accelerates. Untreated advanced colorectal cancer can cause bowel obstruction, perforation of the colon wall (a life-threatening emergency), severe internal bleeding, organ failure as it metastasizes, and ultimately death.
The stark reality is this: a disease that is roughly 91 percent survivable when caught early becomes roughly 15 percent survivable when caught late. The difference between those two numbers is screening.
Arizona Resources for Seniors
If you are a senior living in Arizona, you have access to state-specific programs, organizations, and health systems that can help you get screened and connect you with support if you need it. Here are the resources most relevant to Arizona seniors.
Cancer Support Community Arizona (CSCAZ)
Cancer Support Community Arizona is one of the most valuable organizations in the state for anyone impacted by cancer. For colorectal screening specifically, CSCAZ offers free at-home screening kits so you can take a first step toward early detection in the privacy of your own home. They also provide over 100 free programs per month including support groups, cancer resource navigation, nutritional counseling, educational seminars, and mind-body therapies. All programs are free of charge and open to cancer patients, their families, and caregivers.
CSCAZ also partnered with the Maricopa County Health Department on a pilot program providing transportation support for cancer screenings, addressing one of the biggest barriers rural and underserved seniors face.
Website: cscaz.org Phone: (602) 712-1006
AHCCCS — Arizona’s Medicaid Program
AHCCCS (Arizona Health Care Cost Containment System, pronounced “Access”) is Arizona’s Medicaid program. If you are a low-income senior who qualifies, AHCCCS covers preventive screenings including colorectal cancer screening. Arizona expanded Medicaid under the ACA, which means coverage for colorectal screening with no copays for newly eligible beneficiaries.
For seniors who need long-term care, the Arizona Long Term Care System (ALTCS) is the AHCCCS program for seniors and physically disabled adults requiring nursing facility-level care. Unlike many states, ALTCS is an entitlement with no waitlist. Single applicants must have income at or below $2,982 per month and assets at or below $2,000.
To find out if you qualify for AHCCCS, call 1-855-432-7587 or visit azahcccs.gov.
Arizona Digestive Health
Arizona Digestive Health is a network of board-certified gastroenterologists with locations across the state, including the Phoenix metro area and surrounding communities. Their physicians routinely perform colonoscopies and other colorectal cancer screenings. They recommend screening beginning at age 45 for average-risk adults. To schedule a screening, contact the office nearest you through their website.
Website: arizonadigestivehealth.com
Arizona Digestive Institute (Tucson)
For seniors in the Tucson area, the Arizona Digestive Institute offers a Direct Screen Colonoscopy program. This allows qualifying patients to schedule a colonoscopy directly without requiring a separate pre-screening consultation visit first — reducing wait times and making access easier, especially for seniors who may have difficulty with multiple appointments.
Website: arizonadigestiveinstitute.com
Dignity Health Arizona
Dignity Health operates hospitals and medical groups across the state and offers a Fast Track Colonoscopy program (also known as Open Access Endoscopy) that does not require a pre-screening visit or consultation. For seniors who have been putting off screening because they dread the idea of multiple appointments, this is a streamlined option worth asking about. Dignity Health locations are found throughout the Phoenix metro area, the East Valley, and other parts of the state.
Website: dignityhealth.org/arizona
Chiricahua Community Health Centers (Cochise County)
For seniors in southeastern Arizona, Chiricahua Community Health Centers is the largest primary care organization in the region. As a Federally Qualified Health Center, they serve over 35,000 patients annually across fifteen fixed-site clinics and five mobile medical units throughout Cochise County. Services are provided on a sliding-fee scale based on income, making them a critical resource for uninsured or underinsured seniors in rural areas who need screening referrals or primary care. Their mobile units bring medical services directly into remote communities where access to a clinic can mean a long drive.
Website: cchci.org
SEAHEC — Southeast Arizona Area Health Education Center
SEAHEC has served the border region counties of Cochise, Pima, and Santa Cruz since 1985. While SEAHEC is primarily focused on health workforce development and community health worker programs, they partner with local health departments and community health centers to connect seniors with health screenings and services. Their community health workers (“promotoras de salud”) provide outreach in both English and Spanish, and can help connect you with local screening resources. They also collaborate with SEAGO (Southeastern Arizona Governments Organization) Area Agency on Aging to reach seniors in Graham, Greenlee, Cochise, and Santa Cruz counties.
Website: seahec.org
Arizona’s Area Agencies on Aging
Arizona’s seven Area Agencies on Aging cover all 15 counties and can connect seniors with health-related resources, transportation to medical appointments, benefit counseling, and referrals. While they do not provide cancer screenings directly, their trained counselors can help you navigate Medicare coverage questions, find transportation to screening appointments, and connect you with local programs. Here are the regions most relevant to Arizona seniors:
Region I (Maricopa County) — Area Agency on Aging, Region One Phone: (888) 783-7500 Senior HELP LINE: (602) 264-4357
Region II (Pima County) — Pima Council on Aging (PCOA) Phone: (520) 790-7262 Email: help@pcoa.org
Region III (Apache, Coconino, Navajo, Yavapai counties) — Northern Arizona Council of Governments Phone: (877) 521-3500 Offices in Show Low, Flagstaff, Cottonwood, and Prescott Valley
Region IV (La Paz, Mohave, Yuma counties) — WACOG Area Agency on Aging Phone: (800) 782-1886
Region V (Gila, Pinal counties) — Pinal-Gila Council for Senior Citizens Phone: (800) 293-9393
Region VI (Cochise, Graham, Greenlee, Santa Cruz counties) — SEAGO Phone: (520) 432-2528
Region VII (Arizona’s Tribal Communities) — Inter Tribal Council of Arizona Phone: (602) 258-4822
For a complete list, visit the Arizona Department of Economic Security website at des.az.gov or call the DES Aging and Adult Administration.
State Health Insurance Assistance Program (SHIP)
If you are on Medicare and have questions about what colorectal screenings are covered, whether a procedure will be classified as preventive or diagnostic, or how to appeal a bill, Arizona’s SHIP program offers free, one-on-one counseling to Medicare beneficiaries. SHIP counselors are trained to help you understand your benefits and avoid surprise costs. This service is coordinated through your regional Area Agency on Aging.
To reach a SHIP counselor, call (800) 432-4040.
A Note for Rural Arizona Seniors
Arizona is a large state, and many seniors — particularly in Cochise, Graham, Greenlee, Gila, Yavapai, and other rural counties — live far from the nearest gastroenterologist or endoscopy center. Do not let distance be the reason you skip screening. Start with what is accessible: ask your primary care doctor about a FIT test you can do at home, or ask about the new Shield blood test that can be done with a simple blood draw at any appointment. If either of those tests comes back positive, your doctor can then refer you for a colonoscopy and help coordinate transportation and logistics. Your Area Agency on Aging may also be able to help arrange rides to medical appointments.
The at-home and blood-based tests exist specifically to remove barriers for people in exactly this situation. Use them.
The Bottom Line
Colorectal screening saves lives, and there has never been a time when you had more options for how to get screened. Whether you choose a simple at-home stool test, the new Shield blood test that requires nothing more than a routine blood draw, or a full colonoscopy, the most important step is the one where you actually do it.
Talk to your doctor. Bring your family history. Ask your questions. And if cost is a concern, know that programs exist to help — from Medicare’s preventive coverage to nonprofit financial assistance programs that can make screening accessible regardless of your insurance status.
The prep is temporary. The discomfort is brief. But catching colorectal cancer early — or preventing it entirely — is something that lasts the rest of your life.