Cancer symptoms: early signs to be aware of

Understanding common warning signs and when to seek medical advice

Article Author: By Dr David Griffiths, Chief Medical Officer, Teladoc Health UK

Cancer symptoms can often be vague, subtle, and easily mistaken for everyday health issues. This is one of the key challenges in medicine - identifying when common symptoms may point to something more serious.

It’s important to remember that most of the symptoms listed here are usually not caused by cancer. However, they can be, so if you notice a change in your body that doesn’t settle or continues to worsen, it’s important to seek clinical advice. There’s no need to panic, but it is always better to check.

Applying common sense is also important. Cancer is much less common in younger people, and the risk increases with age. Clinicians will always take this into account when assessing symptoms.

General signs to be aware of

Certain symptoms occur across multiple cancer types. On their own, they may be harmless, but if they persist beyond expected timeframes, they should be checked.

1. Unexplained lumps, swelling, or thickening

New lumps in the breast, neck, armpit, groin, or testicles should never be ignored even though most are benign.

Take action: Any lump that persists for more than 2–3 weeks, is getting larger, or feels hard or fixed should be assessed by a clinician.

2. Persistent fatigue

Fatigue is extremely common and has many causes, often lifestyle or infection related. Consider seeking assessment if you have fatigue that is new, unexplained, and doesn’t improve with rest.

Red flag timeframe: Fatigue lasting more than 3–4 weeks, especially if worsening or associated with other symptoms.

3. Pain that does not go away

Persistent pain, such as back pain, abdominal pain, headaches, or bone pain, can sometimes signal cancer.

Red flag timeframe: Pain lasting more than 3–4 weeks, especially if it does not have an obvious cause, is very severe, worsening, or is waking you at night.

4. Unexplained weight loss

If you’re losing significant body weight without trying and there is no obvious reason (stress, dietary change, illness) you should seek advice.

Take action: See a healthcare professional if weight loss occurs without changes in diet or activity.

5. Changes in bowel or bladder habits

These habits do vary in most people. If you have persistent diarrhoea or constipation, blood in stool or urine or are needing to urinate more often.

Take action: non-menstrual blood in the urine always needs assessment; other symptoms, outside of your normal variation, are worth investigating if persistent over a period of weeks.

6. Unusual bleeding or discharge

Bleeding between periods, after sex, after menopause, blood in stool, urine, sputum, or unexplained bruising can be significant.

Take action: Any unexplained bleeding should be discussed with a clinician - do not wait for it to recur.

7. Persistent cough or voice changes

A cough or hoarse voice may linger after an infection. However, a cough that won’t go away, coughing up blood, or ongoing hoarseness does warrant consideration.

Red flag timeframe: Symptoms lasting more than 3 weeks, especially in people who smoke or have smoked.

8. Difficulty swallowing or ongoing indigestion

Feeling that food is sticking, painful swallowing, or indigestion that does not respond to treatment are worth discussing with a GP.

Take action: Symptoms lasting more than 3 weeks despite usual treatment should be reviewed. If food repeatedly ‘comes back up’ that definitely requires assessment.

9. Skin changes or non-healing sores

New or changing moles, sores that do not heal, or skin lesions that bleed or crust can indicate skin cancer.

Red flag timeframe: Changing or bleeding moles should be assessed if you are concerned, as should a sore that is not healed after 4 weeks.

10. Persistent infections or fevers

Most infections are viral and settle. They may occur repeatedly if are often in contact with children, you travel frequently or are run down.

Take action: Recurrent infections or fevers, particularly if making you feel very unwell, occurring over more than 2–3 weeks without a clear cause warrant an opinion.

When to Take Action

A helpful rule is “3 weeks or worsening”:

If a symptom lasts longer than 3 weeks
If it is getting progressively worse
If it is unexplained or unusual for you
If you have more than one unexplained symptom

Most people who experience these symptoms do not have cancer. However, cancer can be difficult to diagnose and is often more treatable when identified early.

Getting symptoms checked, even if they turn out to be minor, can provide reassurance and help ensure that, if something needs attention, it is addressed as early as possible.