Cancer Warning Signs
Informed by recognized medical guidance
If symptoms are severe, worsening, or life-threatening, seek urgent medical care now.
Overview
Cancer warning signs are possible symptoms that could mean cancer is present. They are not a diagnosis, but they are important to know so you can talk to a doctor if you notice them. Early detection of cancer often leads to better outcomes.
Key facts
- Many cancers can be treated successfully if found early.
- Not all lumps or changes mean cancer, but it is always best to have them checked.
- Knowing your body and noticing unusual changes can help catch cancer sooner.
Cancer is common — about 1 in 2 people in the UK will develop some form of cancer in their lifetime. However, most people with warning signs do not have cancer.
Cancer can affect anyone, at any age, but the risk increases as you get older. Some types are more common in certain groups, such as family history or lifestyle habits.
Symptoms
- Sudden, severe headache with no known cause.
- Sudden loss of vision or double vision.
- Seizure or convulsion for the first time.
- Difficulty breathing or choking sensation.
- ⚠Blood in your vomit or coughing up blood.
- ⚠Sudden severe pain in the chest or abdomen.
- ⚠A lump that is growing rapidly or very hard.
- ⚠Unexplained high fever with chills.
Common symptoms
- A lump or swelling anywhere on the body that does not go away.
- Unexplained weight loss (losing a lot of weight without trying).
- Changes in a mole — size, shape, colour, or it starts to bleed or itch.
- A sore that does not heal within a few weeks.
- Persistent cough or hoarseness lasting more than three weeks.
- Changes in bowel habits (like constipation or diarrhoea) that last more than a few weeks.
- Blood in your urine or stools.
- Unexplained pain that does not go away.
Symptoms in children
- Persistent, unexplained fever or night sweats.
- Lumps in the tummy, neck, or under the arms.
- Unexplained bruising or bleeding easily.
- Bone pain that is constant and not from an injury.
- Unusual paleness or tiredness.
Symptoms in older adults
- Unexplained weight loss or loss of appetite.
- Persistent fatigue beyond normal ageing.
- New or worsening pain that does not go away.
- Changes in skin, such as new growths or non-healing sores.
- Difficulty swallowing or feeling that food is stuck.
Causes
Main causes
- Cancer is caused by changes (mutations) in the DNA of cells, which make them grow out of control.
- These changes can be inherited or happen over time due to exposure to certain substances or factors.
Risk factors
- Smoking or tobacco use.
- Excessive alcohol consumption.
- Unhealthy diet (high in processed foods, low in fruits and vegetables).
- Lack of physical activity.
- Being overweight or obese.
- Exposure to harmful UV rays from the sun or tanning beds.
- Certain viruses, such as human papillomavirus (HPV) or hepatitis B and C.
- Family history of certain cancers.
When to see a doctor
See a doctor urgently if:
- Any symptom that is new, persistent, and worrying — see a doctor within a few days.
- A lump or swelling that you have not had checked before.
- Unexplained bleeding or discharge.
- Unintentional weight loss over a few weeks.
Book a routine appointment if:
- Changes in a mole that are not urgent but still need checking at your next appointment.
- Persistent cough that is not going away but you are able to see the doctor within a week or two.
- Bowel habit changes that last a few weeks but are mild.
Diagnosis
Your doctor will start by asking about your symptoms and medical history, then do a physical exam. If they suspect cancer, they will order tests to look for abnormal cells.
Tests that may be done
- Blood tests to check for markers or anaemia.
- Imaging scans such as X-ray, ultrasound, CT, or MRI to see inside the body.
- Biopsy — taking a small sample of tissue to look at under a microscope.
- Endoscopy — using a thin, flexible tube with a camera to examine inside organs.
- Screening tests like mammograms (for breast) or colonoscopy (for colon).
What to expect at your appointment
Being tested for cancer can be stressful, but your healthcare team will guide you through each step. Tests are usually done as an outpatient, and results can take a few days to a couple of weeks. If cancer is found, you will be referred to a specialist team for further care.
Treatment
Treatment for cancer depends on the type, stage, and location, as well as your overall health. The main goal is to remove or destroy cancer cells while protecting healthy cells. Treatment plans are tailored to each person.
Self-care at home
- Follow your treatment plan exactly as discussed with your doctor.
- Get plenty of rest and eat a balanced diet to keep your strength up.
- Stay active as much as you feel able — even gentle walks can help.
- Manage side effects by talking to your care team — many can be controlled.
Medical treatments
Common treatment approaches include surgery to remove the tumour, chemotherapy (drugs that kill fast-growing cells), radiation therapy (high-energy beams to destroy cancer), targeted therapy (drugs that attack specific cancer cells), hormone therapy (for hormone-sensitive cancers), and immunotherapy (boosting your immune system to fight cancer). Your doctor will discuss the best options for you. (No specific drug names or doses are listed here.)
When is surgery considered?
Surgery is often used if the cancer is in one area and can be removed completely. It may be combined with other treatments before or after.
Living with this condition
Living with cancer can be challenging, but many people manage well with support. Your healthcare team will help manage symptoms and side effects. It helps to keep a routine, ask for help when needed, and stay in touch with loved ones.
Lifestyle tips
- Avoid smoking and limit alcohol.
- Protect your skin from the sun.
- Stay physically active to reduce fatigue and improve mood.
- Get enough sleep and rest when you are tired.
Diet and exercise
Eat a variety of fruits, vegetables, whole grains, and lean proteins. Avoid processed foods and sugary drinks. Gentle exercise like walking, yoga, or swimming can help maintain strength and reduce stress. Always check with your doctor before starting a new exercise routine.
Mental health and emotional wellbeing
A cancer diagnosis can cause fear, anxiety, and sadness. It is normal to feel overwhelmed. Talk to a counsellor or join a support group. If you ever feel like harming yourself or have thoughts of suicide, please call a crisis helpline immediately.
Prevention
Not all cancers can be prevented, but you can lower your risk by avoiding tobacco, limiting alcohol, eating a healthy diet, staying active, and protecting your skin from the sun. Getting vaccinated against HPV and hepatitis B can prevent some cancers.
Vaccines
The HPV vaccine protects against the human papillomavirus, which can cause cervical, anal, and other cancers. The hepatitis B vaccine reduces the risk of liver cancer.
Screening programmes
Screening tests can find cancer early, even before symptoms appear. Common screening programmes include mammograms for breast cancer, cervical smears (Pap tests) for cervical cancer, and bowel cancer screening (such as faecal immunochemical test or colonoscopy). Talk to your doctor about which screenings are right for you based on your age and risk.
Complications
If left untreated
- Cancer can grow and spread to other parts of the body (metastasis).
- It can cause severe pain, blockages in organs, or damage to vital functions.
- Untreated cancer can lead to serious illness and death.
Long-term outlook
Many cancers are treatable, especially when caught early. Treatments improve all the time, and survival rates have increased greatly over the last few decades. Even for advanced cancers, there are ways to manage symptoms and maintain quality of life. Hope and support are always available.
Find support
International organisations
Local organisations
- Cancer Research UK ↗ · United Kingdom
- Macmillan Cancer Support ↗ · United Kingdom
- American Cancer Society ↗ · United States
Helplines
External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.
Always verify with your doctor
Health guidelines vary by country and region. The information in this article is based on international clinical guidelines but may not reflect the specific guidelines, medications, or practices in your country. Always discuss your health concerns with your own doctor or healthcare provider, and refer to your local national health guidelines where available.
Important notice This information is for educational purposes only. It does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your specific situation. If you are experiencing a medical emergency, call your local emergency services immediately.
Related conditions
Sources and guidance
This article is educational and is prepared with reference to recognized health information and clinical guidance sources where available. Specific source links may vary by topic.
Last updated: July 16, 2026
Educational note: This information is for education only and is not a diagnosis.
Use it to support, not replace, advice from a licensed clinician.
If symptoms are severe, worsening, or urgent, call your local emergency number or seek emergency care.
Guidance may differ by country or region. Confirm local recommendations with a qualified healthcare provider.