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Some people experience heavy night sweats that soak their clothing or bedding, even when the bedroom is cool.
Night sweats can also occur because of menopause, medication effects, infections, hormonal conditions, or other medical problems.
A fever alone is not a reliable indicator of cancer. The broader pattern matters, including how long it lasts and whether other symptoms are present.
When to seek help: Arrange an evaluation for recurring unexplained fevers or drenching night sweats, especially if accompanied by swollen lymph nodes, persistent fatigue, or unexplained weight loss.
13. A Mouth Sore That Does Not Heal
Mouth ulcers are common and usually heal within a week or two. A persistent sore, red or white patch, lump, or unexplained area of bleeding deserves closer attention.
Oral cancers can affect the tongue, gums, inner cheeks, lips, and floor of the mouth. Other possible symptoms include persistent mouth pain, difficulty chewing, changes in speech, or difficulty swallowing.
Tobacco use, heavy alcohol consumption, and certain infections can increase the risk of some oral cancers, although oral cancer can also occur in people without these risk factors.
What to do: Arrange a dental or medical examination for a mouth sore that has not healed within about two to three weeks, or sooner if it is growing, bleeding, or accompanied by a lump.
14. Persistent Bone or Joint Pain
Pain is a common symptom of many conditions, including arthritis, muscle strain, injuries, and nerve problems.
Nevertheless, persistent unexplained bone pain can sometimes be associated with bone cancer or cancers that have spread to the bones. The pain may gradually worsen, occur at night, or persist despite ordinary rest.
These patterns do not prove cancer is present. Many non-cancerous conditions can cause similar symptoms.
Pay attention to: Pain that continues without a clear cause, progressively worsens, or occurs with swelling or unexplained weight loss.
Seek urgent care if severe pain develops after a minor injury, particularly if a bone fracture is suspected.
15. Unexplained Bruising or Bleeding
Bruises often occur after minor bumps, and some medications make bruising more likely. However, repeated unexplained bruises or unusual bleeding may indicate a problem that requires investigation.Get Health Tips
Certain blood cancers, including leukemia, can interfere with normal blood cell production. This may lead to easy bruising, frequent nosebleeds, bleeding gums, or tiny red or purple spots on the skin.
Other causes include low platelet counts, liver disease, medication effects, and nutritional deficiencies.
When to seek medical advice: Arrange an assessment for persistent unexplained bruising or bleeding, especially if accompanied by fever, fatigue, pale skin, or frequent infections.
Heavy bleeding, severe weakness, or fainting requires urgent medical care.
16. Frequent Infections
The immune system protects the body against many infections. Some cancers, particularly certain blood cancers, can affect the production or function of immune cells.
As a result, a person may experience repeated infections, infections that are unusually severe, or illnesses that take longer than expected to resolve.
However, frequent infections have many possible explanations, including exposure to germs, diabetes, immune disorders, and some medications.
What matters: Repeated or unusually severe infections should be discussed with a healthcare professional, particularly when combined with unexplained fever, night sweats, bruising, or persistent exhaustion.
Do not assume that frequent colds alone mean you have cancer.
17. Changes in Urination
Changes in urination can occur for many reasons, including urinary infections, diabetes, prostate enlargement, medications, and changes in fluid intake.
Possible warning signs include persistent blood in the urine, unexplained pain during urination, or a lasting change in urinary frequency.
Bladder cancer can cause blood in the urine, sometimes without pain. Prostate cancer may cause urinary symptoms in some cases, although early prostate cancer often causes no symptoms at all.
Difficulty starting urination, a weak stream, or frequent nighttime urination is often associated with non-cancerous prostate enlargement rather than cancer.
When to seek advice: Discuss persistent urinary changes with a healthcare professional, and always have unexplained blood in the urine evaluated.
Inability to urinate, particularly with significant lower abdominal pain, requires urgent care.
18. Loss of Appetite or Feeling Full Quickly
A temporary loss of appetite can follow stress, an infection, or a change in routine. A persistent loss of interest in food or repeatedly feeling full after eating very little may deserve attention.
These symptoms can occur with cancers affecting the stomach, pancreas, ovaries, or other organs. They may also be associated with digestive disorders, depression, medication effects, and other medical conditions.Find Cancer Care
Over time, eating much less than usual can contribute to weakness and unintentional weight loss.
What to do: Seek medical advice if appetite changes persist, particularly if you are losing weight, experiencing abdominal discomfort, or feeling full after only a few bites.
19. New Headaches or Neurological Changes
Headaches are common and are rarely caused by a brain tumor. However, a new or progressively worsening headache, particularly when accompanied by other neurological symptoms, deserves medical evaluation.
Possible warning signs include new seizures, unexplained weakness, changes in vision, difficulty speaking, confusion, or problems with balance.
Brain tumors and cancers that spread to the brain can cause neurological symptoms, but strokes, migraines, infections, and other conditions can produce similar changes.
Seek emergency care if you develop a sudden, extremely severe headache, a first seizure, sudden weakness on one side, new difficulty speaking, or sudden vision loss.
A persistent new headache or a headache that steadily changes should also be assessed by a healthcare professional.
20. Unexplained Changes in a Mole or Skin Growth
Although skin changes were discussed earlier, moles deserve special attention because some melanomas develop from existing moles while others appear as new spots.
The ABCDE guide can help you recognize changes that warrant evaluation:
A — Asymmetry: One half looks different from the other.
B — Border: The edges are irregular, blurred, or uneven.
C — Color: The spot contains different colors or develops a new color.
D — Diameter: The spot is growing; melanomas are often larger than 6 millimeters, although they can be smaller.
E — Evolving: The mole changes in size, shape, color, or appearance.
Not every mole with these features is melanoma, and some melanomas do not follow this pattern.
A spot that changes, bleeds, itches persistently, or looks distinctly different from your other moles should be examined by a healthcare professional.
Why Early Detection Matters
Recognizing possible warning signs does not mean you should expect the worst. Many of the symptoms described above are caused by common, treatable conditions.
Nevertheless, persistent symptoms deserve attention because early evaluation can help identify the underlying cause and determine whether further testing is needed.
Depending on your symptoms and medical history, a healthcare professional may recommend a physical examination, blood tests, imaging, an endoscopic procedure, or a biopsy. The appropriate investigation depends on the specific concern.Relieve Pain
No single blood test can reliably detect every type of cancer, and normal routine blood results do not rule out all cancers.
Screening is also different from investigating symptoms. Screening tests are intended for people without symptoms who meet certain age or risk criteria. Examples include appropriate breast, cervical, and colorectal cancer screening programs. Your clinician can explain which tests are suitable for you.
Who May Have a Higher Risk of Cancer?