Let's Talk About Cancer Screenings and Tests

July 1, 2020

Many types of cancer cause no noticeable symptoms. Others are much easier to beat when you catch them before you have a sign. That’s why regular screenings, which can reveal a potentially cancerous abnormality early on, are so important. So what cancers should you get screened for routinely, and how? And what if that screening reveals something isn’t right? We’ve got you covered. Here’s all you need to know about testing for cancer, from the whys to the when.

What Is Cancer, Technically Speaking? Let’s Recap!

Before delving into the details of cancer screenings, let’s get clear on what the disease is: Cancer develops when abnormal cells grow out of control, due to mutations in our cells’ DNA. While normal cells that divide, get older and die, in a programmatic way, copying DNA as they go, cancer cells are renegades. They don’t stop growing when they should, and they never die. Instead, they mutate, replicate and form tumors. In blood cancers, like leukemia, they form a rebel army, amassing where they shouldn’t be.

Important distinction: A cell that’s abnormal isn’t necessarily cancerous. It could be benign (not cancer), or precancerous or premalignant (likely to become cancer). If it’s malignant, it’s already cancer. This is where screening and testing comes in: They enable doctors to investigate to determine what you’re dealing with.

Cancer cells can start growing pretty much anywhere in the body. And cancer is a label given to a collection of related diseases, which is why treatment ranges so vastly from, say, breast cancer to lymphoma. The spot where these cells start growing—called the primary site of your cancer—determines the type of cancer you have. When those cancer cells spread through your blood or lymphatic system (the network of tissues and organs that flush out toxins, waste, and all sorts of undesirables), the areas they invade are called metastatic sites.

Will a Yearly Physical Exam Find Cancer?

The short answer: Maybe, but possibly not.

While an annual physical exam is key for your doctor to monitor changes in your overall health, including organ and system function, there isn’t one comprehensive blood test (yet) available for cancer screening. Unless you have specific signs and symptoms of cancer, your primary care doctor will likely run panels to test your blood and body for many things, but not for cancer.

That’s why it’s important to stay on top of the recommended screening tests—mammogram, colonoscopy, Pap smear, for instance—for cancers you may be at risk for. A screening is a routine test done for patients without symptoms. If a screening reveals a possible abnormality, or if you have a sign or symptom of cancer, further testing to investigate, known as a diagnostic test, may be done.

Routine cancer screenings can catch the disease before it’s even progressed to the point where you have symptoms, leading to less invasive treatment and best outcomes. Case in point: between 1990 and 2015, the mortality rate for cancer dropped by 25%, and even more for commonly screened cancer types, like colorectal (47% for men and 44% for women) and breast cancer (39% for women). A good percentage of those numbers can be directly correlated with the introduction of screening for those cancer types, according to a 2017 article published in Seminars in Oncology Nursing.

What Screening Tests are Available for Cancer?

Of the 120+ types of cancer, only a handful are regularly screened for, meaning there are set guidelines for when and who should have them, issued by the American Cancer Society (ACS) and U.S. Preventive Services Task Force (USPSTF). The following are recommended:

Breast Cancer Screening

  • What it is: Mammogram (an X-ray of the breast to look for early signs of breast cancer)

  • When to have it:

    • Women ages 40 to 44: can choose to start annual mammograms, covered by insurance

    • Women ages 45 to 54: should get mammograms every year

    • Women ages 55 and older: should get mammograms every 2 years

  • Good to know: Talk to your healthcare professional about the best breast screening plan for you. Regular screening should continue for as long as a woman is in good health and expects to live at least 10 more years. When breast cancer is found with mammography before a noticeable lump develops, it’s usually:

    • Smaller

    • Less likely to have metastasized

    • More likely to be treated with surgery that can save more of a breast (56% vs 32%)

    • Less likely to receive chemotherapy (28% vs 56%)

Cervical Cancer Screening

  • What it is: Pap test (also called a Pap smear, a test on a sample of cells from the cervix to check for abnormalities)

  • When to have it:

    • Women ages 21 to 29: Pap test every 3 years

    • Women ages 30 to 65: Pap test and an HPV test (called co-testing) every 5 years, or a Pap test alone every 3 years

    • Women over age 65 who’ve had regular screening tests with normal results: no continued screening needed.

  • Good to know: Pap tests aren’t new, but they’re certainly effective. Mortality decreased by 80% for cervical cancer after the introduction of the Pap smear (invented by Greek immigrant George Papanicolau in 1929), a researcher reports in Surgical Clinics of North America. You might need to be tested more often because of your family history and other factors—talk to your doctor. A woman who has had a total hysterectomy (removal of the uterus and cervix) for reasons unrelated to cervical cancer should not be tested. Women who have been vaccinated against HPV should still follow screening recommendations for their age group.

Colorectal Cancer Screening

  • How it’s done: Through colonoscopy (a flexible fiber-optic instrument is inserted through the anus to examine the colon for polyps, grows that can turn into cancer) Other times of colorectal screenings include:

    • Fecal occult blood test (FOBT)

    • Stool DNA testing

    • Double-contrast barium enema

    • Flexible sigmoidoscopy

  • When to have it:

    • Men and women ages 45 to 75: colonoscopy every 10 years

    • Men and women ages 76 to 86: discuss with your healthcare provider

    • Men and women over age 85: no continued screening needed

  • Good to know: Colonoscopies find at least 25% of polyps in men and women over the age of 50. And FOBT screenings every 2 years have been found to reduce colorectal cancers by 15%. Talk with your healthcare provider about your risk for colorectal cancer and which tests might be good for you, and talk to your insurance provider about your coverage. All abnormal results on non-colonoscopy screening tests (such as a stool-based test) should be followed up with a colonoscopy. Those at high risk for colorectal cancer because of family and/or personal history or other factors may need to:

    • Start screening before age 45

    • Be screened more often

    • Get a specific test, discussed with your doctor

Lung Cancer Screening

  • What it is: low-dose CT scan (LDCT) (an X-ray screening of your lungs)

  • Who should get it: Those at higher risk of lung cancer because they are:

    • Ages 55 to 74 and in good health AND…

    • Smoke now or quit within the last 15 years AND…

    • Have smoked a pack a day for 30 years OR 2 packs per day for 15 years

  • Good to know: Screening should be discontinued once a person has not smoked for 15 years or has a health issue that limits life expectancy or the ability to have curative lung surgery.

Prostate Cancer Screening

  • What it is: Digital rectal examination (DRE) (doctor inserts a gloved, lubricated finger into your rectum to check the back wall of the prostate gland for enlargement) or a blood test called prostate specific antigen (PSA).

  • Who should get it: The ACS recommends that men make an informed decision with a healthcare provider about whether to be screened through either method, after discussing the risks and benefits with their doctor.

    • African American men and men with a father or brother who had prostate cancer before age 65 should discuss screening with their doctor starting at age 45.
  • Good to know: If you decide to be tested, it’s important to get a PSA blood test with or without a rectal exam. How often you’re tested will depend on your PSA level.

What Are the Issues With Cancer Screening?

Some cancer screening tests have risks—a colonoscopy, for instance, comes with the rare risk of bleeding from where a tissue sample was taken or a polyp was removed. There’s the possibility of a tear in the colon or rectum wall, called a perforation.

In any screening test, you can have a false-positive, meaning it says you have cancer, but on further testing, you actually don’t. There’s also the chance of a false-negative, when the test shows you don’t have cancer, but you do.

False-positive tests can lead to unnecessary stress, further testing, and overdiagnosis, while false-negative tests can delay early treatment. Since false positives and false negatives can happen with any screening, it’s important to know how likely one is to occur, and that is measured by sensitivity and specificity.

  • Sensitivity is the true positive rate—the closer the sensitivity is to 100%, the more likely it is you have the cancer type you’re being screened for.

  • Specificity is the opposite, the true negative rate—the closer the specificity is to 100%, the more likely you don’t have that specific cancer.

Digital mammography, for example, has a sensitivity of 97%, a specificity of 64.5% and diagnostic accuracy of 89.3%. A colonoscopy has a sensitivity of 92.5% and a specificity of 72.3%.

What Are Common Diagnostic Tests for Cancer

How do you know if you have cancer? If you’ve had a positive screening test, or you’ve had a symptom of cancer, or you have a significant family history of the cancer or a genetic factor like a known genetic mutation, your doctor will order a diagnostic test to investigate further. You’ll often receive results in 2-4 days, though it sometimes takes longer.

An exhaustive number of tests can be used for cancer. Here are some of the most common:

Physical Exam and History

Your doctor will examine you physically, checking for any abnormalities, lumps, anything out of the ordinary. He or she will also review your lifestyle, illnesses, and past treatments.


Biopsies remain one of the most common ways that doctors diagnose cancer. A doctor removes potentially cancerous tissue, typically from a mass or lump. It’s removed by:

  • Needle: Commonly used in for bone marrow aspirations, spinal taps, and some breast, prostate, and liver biopsies

  • Endoscopy: A tube-like instrument that can see inside your organs, used for:

    • Bronchoscopy (bronchi, main pathways to the lungs)

    • Colonoscopy (colon)

    • Cystoscopy (bladder and urethra)

    • Laparoscopy (abdominal wall)

    • Laryngoscopy (larynx and throat)

    • Mediastinoscopy (mediastinum, the space between your lungs)

    • Thoracoscopy (surface and lining of the lungs)

    • Upper Endoscopy (upper digestive tract, including esophagus, stomach and first part of small intestine)

  • Surgery

A pathologist then examines the tissue under a microscope and runs tests to determine if it’s cancer. Based on those findings, your doctor will receive a pathologist report, a diagnostic document that will help determine your cancer stage and treatment.

Bodily Fluid Tests

Bodily fluids like urine and blood, can be tested for cancer using tumor marker tests. Tumor markers are substances made by cancer cells or normal cells in response to cancer and they’re found in blood, urine and body tissues.

Urine, for instance, can be used to detect and diagnose kidney, urothelial, bladder, and other cancers. Unfortunately, there isn’t one blood test that can find all cancer types, though one is under investigation that could detect 20+ different cancers, at varying stages, in the blood using next-generation sequencing technology.

The following blood tests are now used to detect specific cancer types:

  • The PSA test is used to detect prostate cancer. While it helps detect cancer, there’s no way to know if that cancer would have advanced enough in a man’s lifetime to cause harm.

  • The CA-125 blood test (often done in concert with a transvaginal ultrasound) can detect ovarian cancer in women with symptoms or who’ve had the cancer type before.

  • The alpha-fetoprotein blood test (often done with an ultrasound of the liver) could help find liver cancer early on in high-risk patients.

Imaging (Radiology Tests)

These tests, which take photos of your insides, can help your doctor determine the type of cancer and its spread, as well as whether your treatment is working. They include:

  • Computed tomography (CT) scan
  • Magnetic Resonance Imaging (MRI)
  • X-rays and other radiographic test
  • Nuclear medicine scan
  • Bone scan
  • PET scan
  • Ultrasound
  • Mammogram
  • Transvaginal ultrasound

If screenings and testing seems like a lot to stay on top of, that’s because it is! Remember, your doctor is your partner in making sure you get the recommended screenings you need. Keep your appointments, don’t wait to do the necessary follow-ups, and definitely reach out if you notice anything weird between appointments. Proper screening paired with self-awareness can help catch cancer early, and treat it effectively.