What early signs of cancer look like
Cancer often develops slowly, and early signs can be easy to miss or mistake for something less serious. The symptoms vary widely depending on which type of cancer is present and where in the body it is growing. Some people have no symptoms at all in the early stages, while others notice changes that prompt them to see a doctor.
The signs listed here are not a diagnosis — many of these symptoms come from common, non-cancerous conditions. What matters is recognizing when something feels different or wrong in your body, and talking to a doctor about it. A doctor can examine you, run tests if needed, and determine what is actually causing the change.
Key Takeaways
- Unexplained weight loss, persistent fatigue, and new or changing lumps or bumps warrant a conversation with your doctor.
- Bleeding or discharge that is not normal for you — including blood in stool, urine, or cough — should be reported to a healthcare provider.
- Skin changes such as new moles, changes in existing moles, or sores that do not heal may signal a problem and deserve medical attention.
- Persistent pain, difficulty swallowing, or changes in bowel or bladder habits lasting more than a few weeks are worth discussing with a doctor.
- Many of these symptoms are caused by treatable conditions that are not cancer, but only a medical evaluation can determine the cause.
Lumps, bumps, and swelling you can feel or see
A new lump or bump under the skin, or swelling in the neck, armpit, or groin, is one of the most common signs people notice. These lumps may be firm, painless, and grow slowly over time. Some are moveable under the skin; others feel fixed in place.
Swelling can also appear in the face, arms, or legs if cancer is blocking lymph vessels or blood vessels. The swelling may be gradual and easy to overlook at first. Any new lump or persistent swelling that lasts more than a few weeks should be checked by a doctor, even if it does not hurt.
Bleeding and discharge that is not normal for you
Blood where it should not be is always worth investigating. This includes blood in the stool (which may look dark or tarry), blood in the urine (which may turn urine pink or red), or blood in vomit or sputum (what you cough up). Unusual vaginal bleeding — between periods, after menopause, or heavier than normal — also falls into this category.
Discharge from the nipple, especially if it is bloody or comes from only one breast, can signal a problem. Any bleeding from the rectum or anus, even if you assume it is from hemorrhoids, deserves a doctor's evaluation. These symptoms are often caused by non-cancerous conditions, but a medical provider needs to rule out cancer.
Skin changes and sores that do not heal
Changes to your skin can be a warning sign. Watch for new moles or growths, or changes in existing moles — including a change in size, shape, or color. A useful guideline is the ABCDE rule: Asymmetry (one half does not match the other), Border irregularity, Color variation (especially if a mole has multiple colors), Diameter larger than a pencil eraser, and Evolving (changing over time).
Sores or wounds that do not heal within a few weeks, especially on the lips, mouth, or genitals, should be examined. Redness, scaling, or itching of the skin that persists and does not respond to over-the-counter treatments may also warrant a doctor's visit. Skin cancer is often the most treatable form of cancer when caught early, so any skin change that concerns you is worth reporting.
Weight loss, fatigue, and fever without an obvious cause
Unexplained weight loss — losing 10 pounds or more without trying, over a period of weeks or months — can be a sign of cancer. This happens because cancer cells use energy and change the way the body processes food. Persistent fatigue that does not improve with rest, or that is worse than your normal tiredness, is another common symptom.
A fever that lasts for weeks without an infection being found, or that comes and goes repeatedly, may indicate cancer. These three symptoms together — weight loss, fatigue, and fever — are sometimes called "B symptoms" and warrant medical evaluation. All three can also result from infections, thyroid problems, depression, or other treatable conditions.
Persistent pain and changes in digestion or urination
Pain that is new, persistent, and without an obvious cause should be discussed with a doctor. This includes pain in the abdomen, chest, back, or bones that does not go away after a few weeks. Pain can be a late sign of cancer, but it can also be an early warning in some cases.
Changes in bowel habits — such as constipation or diarrhea lasting more than a few weeks, or a change in the size or shape of stool — may signal a problem. Difficulty swallowing, or the sensation that food is stuck, warrants evaluation. Changes in urination patterns, such as needing to urinate more often or having pain during urination, should also be reported. These symptoms often come from common, treatable conditions like irritable bowel syndrome or urinary tract infections, but a doctor needs to determine the cause.
Cough, hoarseness, and breathing changes
A cough that lasts more than three weeks, especially if you do not usually cough or if the cough is different from your normal pattern, deserves attention. Coughing up blood or blood-tinged sputum is a reason to see a doctor promptly. Hoarseness that lasts more than a few weeks, or a change in your voice that does not improve, may indicate a problem in the throat or lungs.
Shortness of breath, wheezing, or chest pain that is new or worsening should be evaluated. These symptoms can come from many causes — allergies, asthma, bronchitis, or heart problems — but cancer must be ruled out. If you smoke or have a history of smoking, these symptoms are especially important to report, as your risk for certain cancers is higher.
When to contact a doctor
You do not need to wait for multiple symptoms to appear. A single symptom that is new, persistent, and unusual for you is reason enough to contact your doctor. Most symptoms that last more than a few weeks warrant a medical evaluation, even if you think they are probably nothing serious.
Be specific when you describe your symptoms: when they started, how they have changed, whether they are constant or come and go, and what makes them better or worse. Bring a list if you have noticed several changes. Your doctor may perform a physical exam, order blood tests, imaging studies, or other tests to determine what is causing your symptoms. Remember that many of these signs point to conditions that are not cancer and are treatable.
Frequently Asked Questions
Does having one of these symptoms mean I have cancer?
No. Most people who experience these symptoms do not have cancer. Common conditions like infections, hormonal changes, digestive problems, and stress can cause many of the same signs. Only a medical evaluation can determine the actual cause of your symptoms.
How long should I wait before seeing a doctor about a symptom?
If a symptom is new, unusual for you, and lasts more than a few weeks, contact your doctor. You do not need to wait months. Early evaluation is helpful whether the cause is cancer or something else, because many conditions improve faster when caught sooner.
Are there symptoms that appear only in advanced cancer?
Some symptoms, like severe pain or difficulty swallowing, may appear later in cancer's development. However, many cancers cause symptoms early on. This is why any persistent, unexplained change in your body warrants a doctor's visit — catching cancer early generally leads to better outcomes.
What should I do if I notice a symptom but feel nervous about seeing a doctor?
It is normal to feel anxious about medical visits. Remember that doctors evaluate symptoms like these every day, and most turn out to be non-cancerous conditions. Calling your doctor's office to describe what you have noticed is a good first step — they can advise whether an appointment is needed and help ease your concerns.
Can cancer be present without any symptoms?
Yes. Some cancers, particularly in early stages, cause no noticeable symptoms. This is one reason screening tests — such as mammograms, colonoscopies, and Pap smears — are recommended for certain age groups and risk factors. Talk to your doctor about which screening tests may be right for you.