Detecting cancer early dramatically improves survival, and for most common cancers, specific screening tests exist that can catch the disease before symptoms ever appear. Early-stage lung cancer, for example, has a 61% five-year survival rate, while late-stage lung cancer that has spread drops to just 7%. That pattern holds across nearly every cancer type, which makes knowing your screening schedule and paying attention to your body two of the most powerful things you can do.
Screening Tests by Cancer Type
Routine screening is the backbone of early detection. These are the tests recommended for people at average risk, meaning no strong family history or known genetic factors.
Breast cancer: Mammograms every two years for women aged 40 to 74. If you have dense breast tissue (classified as category C or D on your mammogram report), a standard mammogram can miss tumors hidden behind dense tissue. A 3D mammogram helps radiologists see past those dense areas. In some cases, your doctor may add an ultrasound or MRI, though supplemental imaging does carry a higher chance of false positives that require follow-up testing.
Colorectal cancer: Screening starts at age 45 for everyone. You have several options. A colonoscopy is done every 10 years and has the advantage of removing precancerous polyps during the procedure itself. If you prefer a less invasive route, a FIT test (a simple stool sample that detects blood) is done yearly. Cologuard, which checks stool for both blood and DNA markers shed by colon cells, is repeated every three years. Any positive result on a stool-based test still requires a follow-up colonoscopy, so these aren’t a way to avoid one entirely, just a way to reduce how often you need one.
Cervical cancer: For women aged 21 to 29, a Pap smear every three years. Starting at 30, you can continue with a Pap every three years, switch to HPV testing alone every five years, or combine both tests every five years. Screening generally stops at 65 if recent results have been normal.
Lung cancer: Annual low-dose CT scans for adults aged 50 to 80 who have a smoking history of 20 pack-years or more and either still smoke or quit within the last 15 years. A pack-year means averaging one pack per day for one year, so someone who smoked two packs daily for 10 years also qualifies. Most insurance plans and Medicare cover this screening.
Prostate cancer: PSA blood testing is available but not universally recommended because elevated levels don’t always mean cancer. A PSA above 4.0 ng/mL is generally considered the threshold for further investigation, though some doctors use a lower cutoff of 2.5 ng/mL for younger men and a higher one around 5.0 ng/mL for older men. The decision to screen is typically a conversation between you and your doctor, weighing your age, race, and family history.
Warning Signs Worth Knowing
Screening catches cancers that haven’t produced symptoms yet, but not every cancer has a screening test. Knowing the physical signals that warrant a doctor’s visit fills in the gaps. The American Cancer Society uses the acronym CAUTION to organize seven classic warning signs:
- Change in bowel or bladder habits: persistent diarrhea, constipation, pain during urination, or blood in your stool or urine.
- A sore that doesn’t heal: any wound or lesion that persists, grows, or worsens despite treatment.
- Unusual bleeding or discharge: from the nipples, genitals, or any other part of the body without an obvious cause.
- Thickening or lump: especially in the breast or testicles, but anywhere on the body.
- Indigestion or difficulty swallowing: that persists and isn’t explained by diet or a known condition.
- Obvious change in a wart or mole: new appearance, growth, or altered texture.
- Nagging cough or hoarseness: that lingers for weeks without a respiratory infection.
Unexplained weight loss is another red flag. Losing more than 10 pounds without changing your diet or exercise routine can sometimes signal advanced disease. None of these symptoms means you have cancer, but each one is worth investigating promptly rather than waiting.
How to Check Your Skin
Skin cancer is one of the few cancers you can visually monitor at home. The ABCDE rule gives you a framework for evaluating moles and spots:
- Asymmetry: one half of the mole doesn’t match the other.
- Border: edges are ragged, notched, or blurred, or pigment seems to spread into surrounding skin.
- Color: the mole has multiple shades of brown, black, or tan, or contains areas of white, red, pink, or blue.
- Diameter: larger than about 6 millimeters (roughly the size of a pencil eraser), though melanomas can be smaller.
- Evolving: the mole has changed in size, shape, or color over the past few weeks or months.
A monthly self-check in good lighting, using a mirror for hard-to-see areas like your back, is a simple habit that catches changes early. Photograph moles you want to track so you have a baseline for comparison.
When Family History Changes the Timeline
Standard screening schedules assume average risk. If your family history includes certain patterns, you may need to start screening earlier or get tested for inherited gene changes. Genetic counseling and possible BRCA1/BRCA2 testing are typically recommended if you have any of the following factors: a family member who carries a known BRCA mutation, Ashkenazi Jewish heritage, a personal or family history of breast cancer diagnosed at 50 or younger, or a personal or family history of ovarian cancer, male breast cancer, pancreatic cancer, or high-risk prostate cancer.
Carrying a harmful BRCA change doesn’t guarantee cancer, but it substantially raises lifetime risk for breast and ovarian cancers. People who test positive often begin mammograms and MRIs years before the standard age of 40, and they may discuss risk-reducing options with their care team. Genetic counseling before testing helps you understand what results would and wouldn’t mean for you, and whether testing makes sense given your specific history.
Multi-Cancer Blood Tests
A newer category of screening, called multi-cancer early detection (MCED) tests, analyzes cell-free DNA fragments circulating in your blood. These fragments carry chemical patterns that differ between cancerous and healthy cells. The most prominent test, called Galleri, is commercially available as a lab-developed test and screens for signals from more than 50 cancer types, many of which have no standard screening today.
In a study of cancer survivors enrolled in the PATHFINDER trial, Galleri had a specificity of 99.3%, meaning it rarely produced false cancer signals in people without cancer. When it did detect a signal, it correctly identified the organ of origin about 89% of the time. The positive predictive value, however, was 45%, which means that roughly half of positive results turned out not to be cancer on follow-up. These tests are designed to complement standard screening, not replace it. They are not yet covered by most insurance plans, and large-scale trials are still evaluating whether catching these cancers through a blood draw translates into longer survival.
Building Your Own Screening Plan
The most effective early detection strategy combines three layers: following the age-based screening schedule for your sex and risk level, knowing the physical warning signs that should prompt a visit, and doing simple self-checks like skin exams and breast or testicular awareness. If you have a family history of cancer, particularly in a first-degree relative diagnosed young, bring it up with your doctor so your screening timeline can be adjusted.
Keeping a record of your screening dates helps you stay on track. Colorectal screening every 10 years is easy to let slip, and cervical screening every 3 to 5 years can blur together. A note in your calendar or phone with your next due date takes 30 seconds and removes the guesswork.