When you read about cancer or hear that a friend or loved one has received a cancer diagnosis, it’s natural to be full of questions.

Could you have a cancerous tumor somewhere? How long can you have cancer without knowing about it? Should you be screened?

It’s true that some cancers are diagnosed only after symptoms develop. And this may be after the disease has spread or a tumor has grown large enough to be felt or seen in imaging tests.

But many types of cancers can be diagnosed early, before symptoms form. You have the best chance at survival and a healthy quality of life if your cancer is diagnosed and treated in its early stages.

This article will explore which types of cancers are more likely to go undetected, and how to increase your chances of catching potential cancers early.

Some cancers are more easily detected than others. For example, certain types of skin cancer can be diagnosed initially just by visual inspection — though a biopsy is necessary to confirm the diagnosis.

But other cancers can form and grow undetected for 10 years or more, as one study found, making diagnosis and treatment that much more difficult.

This table provides an overview of common cancers that often display little or no symptoms early on, and how they’re typically detected and diagnosed:

Type of cancerHow it’s typically detected and diagnosed
testicular cancerWhen cancer originates in one or both testes, a man can go a long time without any obvious signs or symptoms. Regular testicular self-checks can usually find a telltale lump within the scrotum, but not always.
cervical cancerSymptoms often don’t appear until the cancer is in its later stages. Getting regular Pap smears can help detect precancerous cells and lead to treatment that can stop them from becoming cancerous.
pancreatic cancerSymptoms can be subtle and don’t usually become noticeable until the cancer is in its advanced stages. Survival rates are low because of this.
breast cancerAs with testicular cancer, self-checks can often detect lumps or other changes in the breast that indicate early stage breast cancer. Regular mammograms are also critical in detecting tumors when they’re still small and no other obvious symptoms are present.
prostate cancerEarly on, there are usually no symptoms. A prostate-specific antigen (PSA) test, which is usually part of a man’s regular blood work, can detect markers in the blood associated with prostate cancer.
ovarian cancerSymptoms may not be obvious at first, but when they do arise, they’re sudden and persistent. An annual Pap smear doesn’t detect ovarian cancer. Tests that may be used to diagnose ovarian cancer include a complete blood count, a cancer antigen test, and other germ cell tumor tests.
lung cancerSigns of lung cancer include frequent cough and hoarseness. A doctor will diagnose it with a physical exam, imaging tests, and a microscopic exam of sputum (if you produce phlegm when you cough).
skin cancerWhile you may not feel any symptoms early on, changes to your skin’s appearance, even with small moles or spots, can be early signs of skin cancer. It’s important that you do all-over skin checks and have regular dermatologist skin exams, too.
colon cancerThis slow-growing cancer may linger for a long time before symptoms appear. A colonoscopy remains the best test to find precancerous and cancerous colon polyps.
kidney cancerKidney cancer doesn’t usually cause any symptoms in its early stages. A complete blood count and physical exam are often the first indications that one or both kidneys have cancer. The survival rate for a cancer that hasn’t spread beyond one kidney is usually high.

Symptomatic vs. asymptomatic cancer

When cancer or any condition is present but there are no noticeable symptoms, it’s said to be asymptomatic.

Many cancers are asymptomatic in their early stages, which is why regular screenings are so important.

Cancers that trigger obvious symptoms early on are called symptomatic cancers. These types of cancers need a prompt diagnosis to be treated successfully.

While sudden or severe symptoms don’t automatically indicate cancer, the sooner you get a diagnosis, the sooner you can begin treatment, or have peace of mind that the cause of your symptoms is benign.

Healthline

This table shows early and later stage symptoms for asymptomatic types of cancers:

Cancer typeEarly symptomsLater stage symptoms
bladder cancerblood in urinelower back pain; inability to urinate
breast cancerlump in breast swelling of breast or arm; pain
colon and rectal cancerchanges in bowel habits; bloody stool unexplained weight loss; nausea; weakness
endometrial cancerabnormal bleedingabdominal pain and bloating; changes in bowel habits
kidney cancerlower back pain, often on one side; blood in urineunexplained weight loss; fever
leukemiaflu-like symptoms; easy bruisingbone and joint pain; weakness; swollen lymph nodes
liver canceryellowing skin (jaundice); right side painabdominal pain; vomiting; weakness
lung cancerpersistent or worsening cough; coughing up bloodfluid in the lungs; severe fatigue; shortness of breath
melanomamole that has an irregular shape or is darkeninghardened lump under the skin; swollen lymph nodes
non-Hodgkin’s lymphomaswollen, painless lymph nodes; fatigueweight loss; fevers; abdominal pain; night sweats
pancreatic cancerjaundice; back pain; fatigueswelling; digestion problems; weight loss
prostate cancerdifficulty urinating; blood in urinebladder problems; losing bowel control; groin soreness
thyroid cancerlump in neck; voice changesbreathing problems; sore throat; difficulty swallowing

Signs and symptoms of disease can be two different things:

  • A sign is something that can be observed by another person, such as a change in skin color or wheezing.
  • A symptom is something you feel, such as fatigue or pain, that isn’t obvious to others.

The nature of cancer signs and symptoms differ greatly, depending on where the cancer is located.

Bladder cancer, for instance, causes blood in the urine, while brain cancer triggers terrible headaches.

When do signs and symptoms first appear?

Typically, cancer signs and symptoms first appear when the cancerous tumor or mass has grown large enough that it begins to push against nearby organs and tissue, blood vessels, and nerves.

This can lead to pain, a change in how the nearby organs function, or both. A brain tumor pressing against the optic nerve will affect vision, for example.

Some cancers are fast moving, such as liver and pancreatic cancers. Prostate cancer, however, is usually slow moving. This is why many older men with prostate cancer forego treatment; they’re more likely to die with prostate cancer than because of it.

Screenings for certain cancers should be part of your normal preventive healthcare. These include cancers of the:

  • prostate
  • breast
  • colon and rectum
  • cervix
  • skin

Your age, sex, family history, and your own medical history will dictate when routine screenings should begin and how often they should be done.

If you’re concerned about symptoms associated with various cancers, then you shouldn’t hesitate to see your doctor.

Signs that warrant an immediate trip to a doctor

Some common cancer signs that should result in a visit to the emergency room or to a doctor as soon as possible include:

  • coughing up mucus tinged with blood
  • blood in stools or urine
  • lump in the breast, testicles, under the arm, or anywhere that it didn’t exist before
  • unexplained but noticeable weight loss
  • severe unexplained pain in the head, neck, chest, abdomen, or pelvis

These and other signs and symptoms will be evaluated. Screenings, such as blood and urine tests and imaging tests, will be used if your doctor thinks it’s appropriate.

These tests are done both to help make a diagnosis as well as rule out various causes of your signs and symptoms.

When seeing a doctor, be prepared to share the following information:

  • your personal medical history, including all symptoms you have experienced, as well as when they began
  • family history of cancer or other chronic conditions
  • list of all medications and supplements you take

For some cancers that are screened for on a regular basis, survival rates tend to be high. That’s because they’re often diagnosed early on, before symptoms develop.

The 5-year survival rate for people with localized breast or prostate cancer is nearly 100 percent. (Localized means it hasn’t spread outside the original tissue or organ.) And when diagnosed early, melanoma has about a 99 percent 5-year survival rate.

But catching some cancers early is difficult. There are no regular screening guidelines for some cancers, and symptoms may not show up until the cancer is in its advanced stages.

To help protect yourself from these cancers:

  • Be sure to keep up with your regular blood work and annual physicals.
  • Report any new symptoms to your doctor, even if they seem minor.
  • Talk with your doctor about testing if you have a family history of a particular type of cancer.

If you’re wondering how long you can have cancer without knowing it, there’s no straight answer. Some cancers can be present for months or years before they’re detected.

Some commonly undetected cancers are slow-growing conditions, which gives doctors a better chance at successful treatment. Others are more aggressive and can be more challenging to treat.

To increase your chances of catching potential cancers early, keep up with your recommended cancer screening schedule, and report any signs or symptoms of concern as soon as you can to your doctor.

The earlier you catch cancer and begin treatment, the better your odds of a favorable outcome.