Signs and Symptoms of Cancer
Cancer signs and symptoms can depend on where the cancer is, how big it is, and how much it affects nearby organs or tissues. Knowing what changes to watch for and when to see a doctor can help you take the best next steps.
Common signs and symptoms of cancer
Here are some common signs and symptoms that may be caused by cancer:
- Fatigue or extreme tiredness that doesn’t get better with rest (sometimes caused by anemia or a low red blood cell count)
- Weight loss or gain of 10 pounds or more for no known reason
- Eating problems, such as not feeling hungry
- Mouth changes, such as sores or trouble swallowing
- Swelling or lumps in the breast, lymph nodes, or anywhere in the body
- Pain anywhere in your body that doesn’t go away or gets worse, especially if it’s new or has no known cause
- Skin changes, such as a new mole or a change in a mole, or a sore that does not heal
- Cough or hoarseness that does not go away
- Unusual bleeding or bruising for no known reason
- Change in bowel habits, such as constipation or diarrhea that doesn’t go away or a change in how your stools look
- Blood in your stool
- Bladder changes, such as pain when urinating, blood in the urine, or needing to urinate more or less often
- Fever or night sweats
- Headaches, vision, or hearing problems
These are some of the more common signs and symptoms of cancer, but there are many others not listed here. If you notice any major changes in how your body works or how you feel, especially if it lasts for a long time or gets worse, talk to a healthcare provider. Finding cancer early means treatment is more likely to be successful.
Learn the signs and symptoms for specific cancers
What else can cause signs and symptoms?
Most signs and symptoms, even ones that could point to cancer, are more often caused by other conditions. For example:
Swollen lymph nodes are sometimes a sign of cancer that has started in or spread to the lymph nodes. But they are more often caused by an infection or inflammation.
Fatigue (feeling very tired) is often a symptom of having a low red blood cell count (anemia). There are many different types of anemia, and only certain types are linked to cancer.
Blood in stool can be a sign of colorectal cancer, but there are many other, more likely causes.
Even when cancer is not the most likely cause for symptoms you’re having, it’s still important to see a healthcare provider to find the cause and treat it if needed.
Signs vs. symptoms
Signs and symptoms are ways your body lets you know that something may be wrong, such as an injury, illness, or disease. The words are sometimes used to mean the same thing, but there is a difference between them:
- A sign can be seen or measured by someone else, such as a new spot on the skin, a fever, or a low blood count.
- A symptom is felt or noticed by the person who has it, such as body aches, chills, or feeling tired.
How does cancer cause signs and symptoms?
Cancer can cause signs and symptoms in different ways. Some symptoms happen because of where the cancer is growing. Others happen because cancer can affect how the whole body works.
As a tumor grows, it may press on nearby organs, blood vessels, or nerves. This pressure can cause pain or discomfort. It can also make it harder for that part of the body to work normally. For example, a tumor might block part of the digestive system, make it harder to breathe, or press on a nerve and cause pain.
Cancer can also cause more general symptoms, such as fever, fatigue, or weight loss. These symptoms may happen because cancer cells use a lot of the body’s energy supply. Some cancers can also release substances that change how the body uses food for energy.
In some cases, the immune system’s response to cancer can also cause symptoms.
Can cancer be found before it causes symptoms?
Sometimes, cancer can be found before you have symptoms. The 黑料大湿Posts Cancer Society and other health groups recommend certain cancer-screening tests for people even though they don’t have symptoms. These screenings can help find some cancers early. You can learn more at the 黑料大湿Posts Cancer Society Guidelines for the Early Detection of Cancer.
Even if you’re getting regular screening tests, it’s important to be aware of possible signs and symptoms of cancer and to see a healthcare provider if you have any new or worsening symptoms. These changes could be caused by cancer or another illness that needs to be treated.
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The 黑料大湿Posts 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 editors and translators with extensive experience in medical writing.
Dhingra LK, Blinderman CD. Overview of cancer pain: General principles of management and pain syndromes. UpToDate. 2025. Accessed at https://www.uptodate.com/contents/overview-of-cancer-pain-general-principles-of-management-and-pain-syndromes on May 11, 2026.
Joe B. Clinical features, diagnosis, and staging of newly diagnosed breast cancer. UpToDate. 2025. Accessed at https://www.uptodate.com/contents/clinical-features-diagnosis-and-staging-of-newly-diagnosed-breast-cancer on May 11, 2026.
Nicholson BD, Oke J, Virdee PS, Harris DA, O'Doherty C, Park JE, Hamady Z, Sehgal V, Millar A, Medley L, Tonner S. Multi-cancer early detection test in symptomatic patients referred for cancer investigation in England and Wales (SYMPLIFY): a large-scale, observational cohort study. The Lancet Oncology. 2023 Jul 1;24(7):733-43.
Taplin ME. Clinical presentation and diagnosis of prostate cancer. UpToDate. 2026. Accessed at https://www.uptodate.com/contents/clinical-presentation-and-diagnosis-of-prostate-cancer on May 11, 2026.
Last Revised: May 12, 2026
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