Some blood cancers, including lymphoma and leukemia, may be associated with unexplained fever and excessive night sweats.
Night sweats become particularly concerning when they are severe enough to soak clothing or bedding despite a comfortably cool sleeping environment.
Other symptoms may include:
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Unexplained weight loss.
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Persistent fatigue.
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Enlarged lymph nodes.
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Recurrent infections.
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Unusual bruising.
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General weakness.
Lymphoma can sometimes produce a combination of symptoms known as B symptoms.
These include unexplained fever, drenching night sweats, and significant unintentional weight loss.
However, these symptoms are not exclusive to lymphoma.
Tuberculosis, other infections, hormonal changes, medication side effects, and autoimmune diseases can also cause them.
Repeated unexplained fever or drenching night sweats deserve medical evaluation, especially when accompanied by persistent lymph node enlargement or weight loss.
A doctor may recommend blood tests, imaging, or additional investigations depending on the clinical findings.
12. Persistent Changes in the Mouth, Tongue, or Nails
The mouth and nails can sometimes reveal changes that deserve medical attention.
Certain oral cancers may produce persistent abnormalities involving the lips, tongue, gums, or inner cheeks.
Possible warning signs include:
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A mouth ulcer that does not heal.
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A persistent red or white patch.
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A lump inside the mouth.
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Unexplained bleeding.
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Persistent pain.
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Difficulty moving the tongue.
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Difficulty swallowing.
Tobacco use, heavy alcohol consumption, and certain HPV infections are among the risk factors associated with some oral cancers.
A mouth ulcer that persists for more than two to three weeks should be examined by a dentist or healthcare professional.
Nail changes can also occur in certain medical conditions.
For example, a dark streak under a nail that is new, changing, widening, or spreading onto surrounding skin should be evaluated by a dermatologist because melanoma can occasionally develop in the nail unit.
Other nail changes, such as clubbing, can occur in association with lung and other diseases, although they have many possible causes.
Persistent or unexplained changes in the mouth or nails deserve attention, particularly when they continue to worsen.
Why Cancer Symptoms Are Often Mistaken for Ordinary Health Problems
One of the biggest challenges in recognizing cancer is that many warning signs are nonspecific.
Fatigue, headaches, stomach discomfort, skin changes, and weight fluctuations are extremely common.
Most people who experience these symptoms do not have cancer.
This creates a difficult balance.
On one hand, people should not panic every time they develop a minor symptom.
On the other hand, persistent or progressive changes should not be ignored.
A useful approach is to consider three important factors:
Duration: How long has the symptom been present?
Progression: Is it becoming more frequent, severe, or noticeable?
Combination: Are several unexplained symptoms occurring together?
For example, occasional tiredness after a busy week is generally different from persistent fatigue accompanied by unexplained weight loss, night sweats, and enlarged lymph nodes.
Similarly, a temporary cough after a cold is different from a cough that continues for weeks, worsens, or produces blood.
The context matters.
How Can Doctors Detect Cancer Early?
Cancer diagnosis depends on the type of symptoms, personal risk factors, age, and physical examination.
There is no single test that detects every type of cancer.
Doctors may recommend several investigations.
1. Blood Tests
Blood tests can identify abnormalities such as anemia, changes in blood cell counts, abnormal organ function, or other clues.
Some cancers affect the production of red blood cells, white blood cells, or platelets.
However, routine blood tests cannot reliably rule out all cancers.
Normal results do not guarantee that cancer is absent.
2. Imaging Tests
Imaging helps doctors examine internal organs and identify suspicious abnormalities.
Common methods include:
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Ultrasound.
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X-rays.
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Computed tomography (CT).
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Magnetic resonance imaging (MRI).
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Mammography.
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Positron emission tomography (PET) in selected circumstances.
The appropriate imaging method depends on the suspected condition.
3. Biopsy
A biopsy involves collecting a small sample of tissue for examination.
For many cancers, examining tissue under a microscope is the most definitive way to establish the diagnosis.
The sample may be obtained through a needle, endoscopy, surgery, or another procedure.
4. Screening Tests
Screening aims to detect certain cancers before symptoms develop.
Examples include:
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Mammography for breast cancer.
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Cervical screening using HPV testing and/or Pap testing.
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Colorectal screening using stool tests or colonoscopy.
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Low-dose CT for eligible people at high risk of lung cancer.
Screening recommendations vary by country, age, personal history, and risk factors.