A clinician may review your weight history, medications, appetite, diet, and other symptoms before deciding which tests are appropriate.
The goal is to identify the cause early rather than assuming that weight loss is either harmless or necessarily caused by cancer.
6. Persistent Fatigue That Does Not Improve With Rest
Everyone feels tired occasionally. Poor sleep, demanding work, stress, exercise, and temporary illness can all cause fatigue.
However, fatigue that persists despite adequate rest or interferes with everyday activities may indicate an underlying medical problem.
Cancer-related fatigue can differ from ordinary tiredness. It may feel disproportionate to the amount of activity performed and may not improve fully after sleeping.
Why can cancer cause fatigue?
Several mechanisms may contribute.
Cancer can cause inflammation that affects energy levels. Some cancers interfere with the production of red blood cells, leading to anemia and reduced oxygen delivery to tissues.
Cancer may also affect appetite, sleep, metabolism, and hormone regulation.
Treatments such as chemotherapy, radiation therapy, surgery, and certain medications can contribute to fatigue as well.
Fatigue may occur with leukemia, lymphoma, and many solid tumors, but it is extremely nonspecific.
Anemia from iron deficiency, thyroid disease, sleep apnea, depression, chronic infection, heart disease, and numerous other conditions can produce similar symptoms.
When should fatigue be checked?
Seek medical advice if fatigue:
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Persists for several weeks without a clear explanation.
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Becomes progressively worse.
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Interferes with normal daily activities.
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Occurs alongside unexplained weight loss or fever.
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Is accompanied by unusual bruising, bleeding, or recurrent infections.
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Develops with persistent pain or other new symptoms.
Sudden, severe fatigue accompanied by chest pain, shortness of breath, fainting, or neurological symptoms requires urgent assessment.
A clinician may recommend blood tests or other investigations based on the pattern of symptoms.
Do not assume that persistent exhaustion is simply a normal part of aging or a busy lifestyle.
7. Changes in Bowel Habits or Persistent Digestive Symptoms
The digestive system naturally varies from day to day. Diet, hydration, stress, travel, medication, and minor infections can all affect bowel movements.
However, a persistent change in bowel habits may require medical investigation.
Colorectal cancer can sometimes cause changes in stool frequency or consistency, rectal bleeding, abdominal discomfort, anemia, or a feeling that the bowel does not empty completely.
Other gastrointestinal cancers can produce symptoms such as difficulty swallowing, persistent indigestion, abdominal swelling, early fullness, or unexplained appetite changes.
These symptoms can also occur with common noncancerous conditions, including hemorrhoids, irritable bowel syndrome, inflammatory bowel disease, ulcers, and food intolerances.
The duration, severity, and combination of symptoms help determine how urgently evaluation is needed.
Symptoms that should not be ignored
Arrange medical assessment for:
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Blood in the stool or rectal bleeding.
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Black, tarry stools without an obvious explanation.
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A persistent change in bowel habits.
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Ongoing abdominal pain or bloating.
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Unexplained iron-deficiency anemia.
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Difficulty swallowing that persists or worsens.
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Repeated vomiting.
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Early fullness accompanied by weight loss or reduced appetite.
Severe abdominal pain, substantial bleeding, or vomiting that prevents you from keeping fluids down may require urgent care.
Why screening matters
Colorectal cancer screening can detect precancerous growths and, in some cases, identify cancer before symptoms develop.
Screening recommendations depend on age, personal history, family history, and local medical guidance.
People with a strong family history of colorectal cancer, certain inherited syndromes, or inflammatory bowel disease may need earlier or more frequent assessment.
Do not wait for symptoms if you are eligible for recommended screening.
Screening and diagnostic testing are different: screening is intended for people without symptoms, while persistent symptoms may require evaluation even if a recent screening test was normal.
8. Persistent Cough, Hoarseness, or Shortness of Breath
Coughs commonly develop because of respiratory infections, allergies, asthma, acid reflux, or environmental irritants.
Most short-term coughs are not caused by cancer. Nevertheless, a cough that persists, changes significantly, or occurs alongside other concerning symptoms should be evaluated.
Lung cancer can cause a persistent cough, coughing up blood, chest pain, shortness of breath, recurrent respiratory infections, or unexplained weight loss.
Other cancers affecting the throat, larynx, or nearby structures can sometimes cause persistent hoarseness, swallowing difficulties, or a sensation of a lump in the throat.
When is a cough concerning?
Medical assessment is appropriate when a cough:
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Lasts several weeks without improvement.
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Becomes progressively worse.
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Produces blood.
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Occurs with persistent chest pain.
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Is accompanied by unexplained weight loss.
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Develops alongside increasing breathlessness.
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Occurs in someone with a significant smoking history or other lung cancer risk factors.
Coughing up blood should be evaluated promptly. Heavy bleeding or bleeding accompanied by breathing difficulty requires emergency care.
Sudden severe shortness of breath, especially with chest pain or fainting, also requires emergency assessment.
The importance of smoking cessation
Smoking is a major risk factor for lung cancer and several other cancers.
Quitting smoking reduces future health risks, although the degree of risk reduction depends on factors such as the duration and intensity of previous smoking.
People who have smoked heavily for many years may qualify for low-dose CT lung cancer screening under specific age and smoking-history criteria in some countries.
Screening eligibility should be discussed with a healthcare professional because the recommendations differ by location.
Persistent respiratory symptoms should not be dismissed simply because someone has smoked for many years or assumes the cough is caused by smoking alone.
9. New or Changing Skin Spots
The skin provides visible clues about many health conditions. Most moles, freckles, and skin spots are benign, but a new or changing lesion can occasionally indicate skin cancer.