Cancer

Cancer is not one disease but a large family — more than two hundred of them — sharing a single mechanism: a cell stops obeying the body's instructions and begins to divide on its own. It can arise in any organ, and also in the blood, the bone marrow and the lymphatic system. Early stages are almost always silent, so what is asked of a person is little but important: notice changes that were not there before, and do not put off the conversation with a doctor. Most worrying signs turn out in the end to belong to far more harmless conditions — but that only becomes clear after they are checked.

How an ordinary cell becomes a tumour

When a cell should divide and when it should make way for a new one is decided by mechanisms written into its DNA. DNA is damaged all the time — by tobacco smoke, ultraviolet light, certain viruses and chemicals, and most often simply by random copying errors. Nearly all such faults are repaired, or the defective cell dies. But when errors accumulate in particular genes, the cell gains the ability to divide without stopping and to ignore the signal to destroy itself.

A mass of such cells forms a tumour. A benign one grows in place, pushing neighbouring tissue aside, and is usually no threat to life. A malignant one grows into the surrounding tissue and destroys it, while individual cells break away and travel in the blood or the lymph to settle in other organs as secondary deposits, or metastases. It is this ability to invade and to spread that separates cancer from a harmless lump, and it is why the size of a tumour counts for less than its stage.

General signs not to write off as tiredness

• a new lump or swelling anywhere on the body, particularly a hard one that does not move;
• weight loss without dieting and without explanation;
• fatigue that does not lift after rest and sleep;
• fever or heavy night sweats dragging on for weeks or coming back;
• pain somewhere that persists and is unlike the pain you are used to;
• bruising without knocks, or bleeding you cannot account for.

None of these on its own means cancer. What matters is something else: that they have appeared for the first time, have lasted longer than three or four weeks, and have no obvious explanation.

Symptoms tied to a particular organ

• Skin. A new mole or a change in an old one — growth, a ragged edge, uneven colour, itching, bleeding. A sore that has not healed for months. Yellowing of the skin and of the whites of the eyes; on brown skin the yellow is easier to spot in the eyes.
• Digestion. Prolonged bloating, heartburn that never troubled you before, diarrhoea or constipation lasting weeks on end, blood in the stool or black tarry stools.
• Mouth and throat. An ulcer that has not healed in three weeks, white or red patches on the lining of the mouth, a hoarse voice lasting more than three weeks, difficult or painful swallowing.
• Lungs. A cough that drags on for a month or more or has changed in character, worsening breathlessness, blood in the phlegm, repeated bouts of pneumonia in the same place.
• Urinary tract. Blood in the urine, even once and even painless. Passing urine more often or with difficulty, a weak stream, getting up at night.
• Genital area. Bleeding between periods, after sex, and above all any bleeding after the menopause. Unusual discharge. A lump in a testicle, blood in the semen, a sore on the penis that will not heal.
• Breast. A lump in the breast or armpit, dimpling of the skin or a pulled-in nipple, a change in shape, discharge from the nipple, persistent redness and flaking around the nipple. In men too.

When delay is not an option

Some situations call not for a routine appointment but for help within hours or days.

• heavy bleeding — from the back passage, from the vagina, when coughing or vomiting;
• sudden severe breathlessness with swelling of the face and neck and distended veins on the neck and chest;
• worsening back pain with numbness or weakness in the legs, or loss of control over the bladder or bowels — in someone with known cancer this signals compression of the spinal cord and is a genuine emergency; help is needed within hours or the damage becomes permanent;
• sudden confusion, relentless vomiting, intense thirst and weakness in someone with a cancer diagnosis;
• a temperature above 38 °C in a person who has recently had chemotherapy — even with no other complaints.

What affects the risk and what you can do about it

Anyone can develop cancer, and in an individual case the cause usually cannot be named. But the factors that shift the odds are known, and some of them can be changed.

• Age. The dominant factor and the only one nothing can be done about: DNA errors accumulate over the years.
• Smoking. Linked not only to the lungs but also to the voice box, oesophagus, bladder and pancreas. Stopping lowers the risk at any age and after any number of years.
• Alcohol. No safe amount has been established; the risk starts rising from small quantities.
• Excess weight and inactivity. Aim for at least 150 minutes of moderate activity a week, vegetables and whole grains on the plate, and less processed meat.
• Ultraviolet light. Shade, clothing, sunscreen of factor 30 or higher, and no sunbeds.
• Viruses. Human papillomavirus and hepatitis B and C. Vaccines exist against the first two — a rare case where a vaccination directly prevents cancer.
• Family history. If several close relatives had the same type of cancer, or developed it young, it is worth discussing genetic testing with a doctor.
• Work and environment. Asbestos, industrial dust, radon in basements, polluted air.
• Chronic conditions. Long-standing acid reflux, inflammatory bowel disease, chronic hepatitis.

Screening stands apart: tests offered to people with no symptoms. Programmes differ from country to country, but they usually include cervical screening, mammography, a stool test for hidden blood or colonoscopy, and in some places low-dose lung scans for long-term smokers. The point is to find changes before symptoms appear, when treatment is simpler and the outcome better. If an invitation arrives, go.

How a diagnosis is made and why the biopsy decides it

The path is usually the same: examination and questioning, then blood tests and imaging — ultrasound, X-ray, scans, endoscopy. All of that shows where a mass is and how far it has spread, but no image says for certain whether it is malignant. Only a biopsy answers that — taking a piece of tissue and examining it under the microscope. The same examination determines the subtype and the features that govern the choice of treatment.

One misconception is worth stating plainly: blood tests for tumour markers are no good for checking a healthy person. They rise with inflammation and with benign conditions and stay normal in some cancers, so a set ordered "just in case" delivers either false alarm and a cascade of pointless investigations, or false reassurance. They are used to monitor a disease already diagnosed, not as a substitute for screening.

What treatment consists of

The plan depends on the type of tumour, its stage, its location and the person's general condition, so there is no standard regimen. A tumour may be removed surgically, irradiated, or acted on with medicines: chemotherapy, which strikes rapidly dividing cells; targeted drugs aimed at a specific fault; immunotherapy, which helps the immune system recognise the tumour; hormone therapy for hormone-sensitive cancers. Most often these are combined.

The decision is not made by one doctor but by a team — oncologist, surgeon, radiation specialist, pathologist. When a cure is not possible, treatment is aimed at holding the disease back and at letting the person live longer and with less suffering; pain relief and supportive care are a full part of the plan, not a sign that the patient has been given up on.

Online consultation

During an online appointment the doctor will go through what worried you in detail: how long the symptom has been there, whether it has changed, whether similar cases have occurred in the family. They will explain which investigations make sense and in what order, help you interpret results and images you already have, and advise which specialist to see in person and how urgently. If you are already in treatment, the appointment is a place to discuss side effects and learn which of them call for immediate attention.

This material is for information only and does not replace medical advice.