Cancer screening is a way to find cancer before you have any symptoms.
The goal is to find cancer early, when it's easier to treat and when people often have better results. But there can also be some downsides, like finding and treating things that wouldn't actually shorten your life.
If you have new symptoms, like a cough that won't go away, losing weight for no reason, blood in your poop, or other unexpected changes in your health, you should talk to your doctor. There might be faster and more direct tests to help figure out what's wrong.
The UCSF Cancer Diagnostic Service is there for people who have a test result that suggests they might have cancer. This includes something found by chance during a test done for another reason, or a positive result from a full-body MRI or blood test. Full-body MRIs done to look for cancer and most cancer screening blood tests are not considered normal medical care and might not be covered by insurance.
What cancer screenings are recommended depends on things like your age, sex, family history, and personal health risks. Common recommendations include:
- Breast cancer: Women age 40 and older should get regular mammograms.
- Colorectal cancer: Adults should start getting regular screenings (like colonoscopies) at age 45.
- Cervical cancer: Women between 21 and 65 should get regular Pap smears or tests for the virus that can cause cervical cancer.
- Lung cancer: Adults 50–80 who used to smoke heavily, or who quit within the last 15 years, should get screened with a low-dose CT scan.
- Prostate cancer: Men age 50 and older should talk to their doctor about screening.
You should talk to your doctor to find out when screening is right for you and how often you should get it.
Even if you feel healthy, cancer can still develop without you knowing it. Many cancers are easiest to treat when they're found early, which is why regular screenings are recommended for people who meet certain age or risk requirements. Talk to your doctor about your health history to figure out the right screening schedule for you.
Risk is different for everyone, and many things can affect it. Age is the biggest risk factor for cancer, but lifestyle and environmental factors also play a role. Smoking and being overweight are linked to a higher risk for many cancers. Alcohol use, diet, and other things also matter. Being exposed to sunlight and cancer-causing substances can also increase the risk of certain cancers. Some people are born with gene changes that make them more likely to get cancer (see below). Your personal risk can help decide what screening is recommended for certain cancers, so you should talk about it with your doctor.
About 1 in 10 cancers are inherited. A family history, especially for certain cancers, might mean that there's an inherited cancer syndrome where specific gene changes are passed down through families. But even if the exact gene changes aren't known, screening might still be a good idea if you have a strong family history. Just because someone in your family has or had cancer doesn't necessarily mean you'll get it too.
If you have a family history of cancer, ask your doctor if genetic testing is right for you. Depending on the type of cancer and how many family members are affected, this might be covered by insurance.
New technologies are being developed that can find special markers released by cancer cells (like DNA pieces, proteins, or other molecules) or that are caused by the body's response to cancer (like changes in the immune system). These blood tests might be for one specific cancer or for multiple cancers (see below). Some blood tests for a single cancer might be covered by insurance.
Some tests can find signs that suggest cancer in multiple parts of the body. These tests are promising and are currently being studied. They come in two types:
- Whole-body MRI (Magnetic Resonance Imaging) is an imaging test that uses strong magnets and radio waves to create detailed pictures of the whole body. It can help find early signs of cancer by spotting unusual things in tissues and organs that might not be seen with other imaging tests.
- Multi-cancer detection (MCD) tests look for multiple cancers from a single sample, usually blood. They are sometimes called multi-cancer early detection (MCED) tests.
For people who are at average risk and don't have symptoms, the chance of a positive MCD test is about 1 in 100. But a positive result doesn't necessarily mean you have cancer. It just means that more testing is recommended to confirm or rule out cancer and find out where it is.
No. None of the tests available now replace regular screening. You should still talk to your doctor about screening for colorectal, breast, cervical, and lung cancer. A lot of the benefit of colorectal and cervical cancer screening comes from preventing cancer from starting in the first place.
While cancer screening can save lives, no test is perfect, and you should know about the following:
- False positives: The test might say you have cancer when you don't, which can cause unnecessary worry and lead to more tests.
- False negatives: The test might miss a cancer, which can give you a false sense of security.
- Overdiagnosis: Some cancers that are found are slow-growing and might not need treatment.
- Side effects of follow-up tests: If a screening test leads to a biopsy or surgery, there are risks related to those procedures.
10. What screening is covered by insurance?
The Affordable Care Act says that many preventive services, including cancer screenings like mammograms and colonoscopies, must be covered at no cost to you. MCD tests and full-body MRIs done to look for cancer are usually paid for out-of-pocket. If a positive result is found, follow-up testing might be covered by insurance. But coverage can vary depending on your plan, so check with your insurance company to see what's included.
No. The tests available now are not meant to replace standard cancer screening. How reliable they are can depend on the specific test and technology used.
Multi-cancer screening is usually not covered by insurance. But if an MCD test is being done as part of a research study, it will be free for the patient.