Cancer Symptoms You Shouldn’t Ignore

woman grimaces with headache pain

The best way to find some cancers early, when they’re small, have not spread, and are easier to treat, is through routine screenings – tests to check for cancer before there are any symptoms of the disease. With cervical and colon cancers, these tests can even prevent cancer from developing in the first place. But for cancer types that have no screenings, and for people who are too young to get routine screenings, symptoms are usually the first sign of cancer.

Knowing what symptoms to look for is complicated because cancer is not just one disease, but a group of diseases that can cause almost any sign or symptom. The signs and symptoms will depend on where the cancer is, how big it is, and how much it affects the organs or tissues. If a cancer has spread (metastasized), signs or symptoms may appear in different parts of the body.

A cancer may cause general symptoms like fever, extreme tiredness (fatigue), or weight loss. This may be because cancer cells use up much of the body’s energy supply, or they may release substances that change the way the body makes energy from food. Cancer can also cause the immune system to react in ways that produce these signs and symptoms. General symptoms can also have other causes, and are in fact more likely to be caused by something that isn’t cancer. But it’s important to have them checked out, just in case. If cancer is not the cause, a doctor can help figure out what the cause is and treat it, if needed.

Research has found that many people ignore symptoms or underestimate how serious they are. In a study conducted in London, researchers found that less than 60% of people who’d experienced symptoms that can be caused by cancer in the previous 3 months had gone to the doctor about them. And hardly any of them considered cancer as a possible cause. The symptoms included unexplained weight loss and change in the appearance of a mole, both of which should be checked out by a doctor right away.

The researchers say their study makes clear that opportunities for cancer to be diagnosed earlier are being missed. And while some symptoms, such as tiredness or coughing, are more likely caused by something other than cancer, no symptom should be ignored or overlooked, especially if it has lasted a long time or is getting worse.

Reasons to see a doctor

  • Weight loss without trying: Losing 10 pounds or more that isn’t on purpose may be a sign of cancer. This happens most often with cancers of the pancreas, stomach, esophagus (tube connecting the mouth to the stomach), or lung.
  • Fever: Sometimes cancer can affect the immune system, making it harder for the body to fight infection that causes fever. It can also be an early sign of leukemia or lymphoma.
  • Fatigue: Extreme tiredness that doesn’t get better with rest may be a symptom of several different cancer types including leukemia, colon cancer, or stomach cancer.
  • Pain: Bone cancer or testicular cancer may cause pain. A headache that does not go away or get better with treatment may be a symptom of a brain tumor. Back pain can be a symptom of cancer of the colon or ovary.
  • Skin Changes: Any wart, mole, or freckle that changes color, size, or shape, or that loses its sharp border should be checked for melanoma or other types of skin cancer. Other skin changes that can be symptoms of cancer include darker looking skin, yellowish skin and eyes (jaundice), reddened skin, itching, or excessive hair growth.
  • Change in bowel or bladder habits: Long-term constipation, diarrhea, or a change in size of the stool may be a sign of colon or rectal cancer. Pain when passing urine, blood in the urine, or a change such as needing to go more or less often than usual could be related to bladder or prostate cancer.
  • Sores that do not heal: Skin cancers may bleed and look like sores that don’t heal. A long-lasting sore in the mouth could be an oral cancer, especially in people who smoke, chew tobacco, or often drink alcohol. Sores on the genital area may either be signs of infection or an early cancer.
  • White spots in the mouth: White patches inside the mouth and white spots on the tongue may be leukoplakia. Leukoplakia is a pre-cancerous area that’s caused by frequent irritation. It’s often caused by smoking or other tobacco use and can become mouth cancer if not treated.
  • Unusual bleeding: Coughing up blood may be a sign of lung cancer. Blood in the stool (which can look like very dark or black stool) could be a sign of colon cancer. Abnormal vaginal bleeding may be a sign of cervical or endometrial cancer. Blood in the urine may be a sign of bladder or kidney cancer. A bloody discharge from the nipple may be a sign of breast cancer.
  • Lump: Many cancers can be felt through the skin. These cancers occur mostly in the breast, testicle, lymph nodes (glands), and the soft tissues of the body. Some breast cancers show up as red or thickened skin rather than a lump.
  • Indigestion or trouble swallowing: Problems that don’t go away may be signs of cancer of the esophagus, stomach, or throat.
  • Nagging cough or hoarseness: A cough that does not go away may be a sign of lung cancer. Hoarseness can be a sign of cancer of the voice box (larynx) or thyroid gland.

Having one or more of these symptoms does not mean you have cancer, or that you’re even likely to have cancer. But if you have one, or if you notice any other big changes in the way your body works or the way you feel, let a doctor know. This is especially true if a symptom lasts for a long time or gets worse. Even if it has nothing to do with cancer, the doctor can find out more about what’s going on and, if needed, treat it.

You may also call American Cancer Society any time, night or day, at 1-800-227-2345 with questions.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Attributions of Cancer ‘Alarm’ Symptoms in a Community Sample. Published December 2, 2014 in PLOS ONE. First author Katriina L. Whitaker, PhD, University College London.

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