Cancer can develop in many different organs, and there is no single set of symptoms that proves cancer is developing. In fact, many symptoms that can occur with cancer are much more commonly caused by infections, inflammation, medications, benign growths, or other conditions. Still, new, unexplained, persistent, or worsening changes should be evaluated by a healthcare professional.
5 Early Warning Signs That Should Not Be Ignored
1. Unexplained weight loss or loss of appetite
Losing weight without deliberately changing your diet or exercise routine can sometimes be an early warning sign.
What to watch for:
- Noticeable weight loss without trying
- Persistent loss of appetite
- Feeling full unusually quickly
- Unexplained weakness accompanying the weight loss
Cancer can alter the body’s metabolism and energy use, and some cancers can reduce appetite. However, unexplained weight loss can also result from thyroid problems, digestive disorders, infections, stress, depression, or other medical conditions. The American Cancer Society specifically lists unexplained weight loss or weight gain of about 10 pounds or more as a symptom that warrants attention.
When to seek medical advice: If weight loss continues without an obvious explanation, particularly if it is accompanied by fatigue, persistent pain, digestive problems, bleeding, or a lump.
2. An unusual lump, swelling, or thickened area
A new lump or swelling anywhere on the body deserves attention, particularly if it persists or changes.
Possible locations include:
- Breast or chest
- Neck
- Armpit
- Groin
- Abdomen
- Testicle
- Under the skin
Some cancers can cause enlarged lymph nodes or a tumor that can be felt as a lump.
Important: A lump does not automatically mean cancer. For example, swollen lymph nodes are commonly caused by infections or inflammation. Cysts and other benign growths can also produce lumps.
A healthcare professional may examine the area and, depending on the location and characteristics, recommend imaging or other tests.
3. Persistent fatigue or unexplained weakness
Everyone becomes tired occasionally. Cancer-related fatigue is different because it may be severe, persistent, and not adequately relieved by sleep or rest.
You might notice:
- Feeling exhausted most of the day
- Lack of energy despite adequate sleep
- Difficulty performing normal activities
- Physical weakness
- Problems concentrating or thinking clearly
Cancer can contribute to fatigue in several ways, including anemia, changes in metabolism, inflammation, or the body’s response to the disease.
However, fatigue is extremely common and can result from anemia, poor sleep, infections, stress, thyroid disorders, nutritional deficiencies, medications, and many other causes.
The important pattern is persistence: unexplained fatigue that continues or progressively worsens should be discussed with a healthcare professional.
4. Unexplained bleeding or changes in normal body functions
Unexpected bleeding can be an important warning sign, depending on where it occurs.
Examples include:
- Blood in the stool
- Blood in the urine
- Coughing up blood
- Unusual vaginal bleeding
- Bleeding that occurs between periods or after menopause
- Frequent or unexplained bruising
- Vomiting blood
Other changes in normal body functions can also be important, including:
- Persistent constipation or diarrhea
- A significant change in stool appearance or bowel habits
- Difficulty urinating
- Pain or blood when urinating
- Persistent difficulty swallowing
- A cough or hoarseness that doesn’t go away
The National Cancer Institute and American Cancer Society both identify unexplained bleeding and persistent bowel, bladder, swallowing, coughing, or voice changes among symptoms that can occur with cancer.
These symptoms have many non-cancerous causes, but unexplained blood should not simply be ignored.
5. Persistent skin changes or a sore that doesn’t heal
Changes in the skin can sometimes be an early indication of skin cancer or another disease.
Watch for:
- A new mole or unusual skin growth
- A mole that changes in size, shape, or color
- A sore that repeatedly bleeds or doesn’t heal
- A scaly or crusty growth
- A skin lesion that continues to change
- Yellowing of the skin or whites of the eyes (jaundice)
- Persistent changes in an existing skin spot
The NCI lists new or changing moles, sores that don’t heal, unusual bleeding or scaling, and jaundice among possible cancer-related signs.
For a changing mole, clinicians often consider features such as asymmetry, irregular borders, uneven color, increasing diameter, and especially change over time. A suspicious skin lesion should be examined rather than trying to diagnose it yourself.
Other possible warning signs
Depending on the type and location of cancer, other symptoms can include:
- Persistent or unexplained pain
- Persistent cough or hoarseness
- Recurring fever or unexplained night sweats
- Difficulty swallowing
- Persistent indigestion or abdominal discomfort
- New breast or nipple changes
- Persistent headaches or neurological changes
- Unexplained vision or hearing changes
- Mouth sores or persistent red/white patches
- Persistent abdominal swelling or fullness
One very important point
Having one of these symptoms does not mean you have cancer. Most people with an isolated symptom will have another explanation. The concern becomes greater when a symptom is new, unexplained, persistent, worsening, or associated with several other changes.
Also, cancer does not always cause symptoms in its early stages. That’s why recommended screening is important even when you feel completely healthy. Screening can detect certain cancers before symptoms develop.
If you tell me your age, sex, and the specific symptoms you’re experiencing (if any), including how long you’ve had them, I can explain what they could mean and what type of medical evaluation is generally appropriate.