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Symptom guide
Common side effects, their causes, and what you can do.
General medical information
This guide offers general orientation and does not replace a medical consultation. Every situation is unique — always talk with your medical team before making decisions about treatment or symptoms.
How to use this guide
Pick a symptom and see what helps. If things get worse, use the Warning signs page.
🌊 Nausea
Nausea is one of the most common effects of chemotherapy and radiotherapy. It happens because the treatment stimulates receptors in your digestive tract and brain. It does not mean you are weak or that the treatment is not working — it is a normal response from your body.
What helps
- ✓Eat small portions every 2–3 hours rather than large meals.
- ✓Choose cold or room-temperature foods — the smell of hot food can make nausea worse.
- ✓Ginger (as tea or biscuits) can reduce nausea for many patients.
When to contact your doctor
Nausea lasting more than 24 hours, repeated vomiting that stops you keeping fluids down, or rapid weight loss need urgent medical contact.
Full escalation guide →😴 Fatigue
Cancer-related fatigue is different from ordinary tiredness — it does not go away after rest and can last for weeks or months. It is caused by the treatment, anaemia, disturbed sleep, or your body's inflammatory response to the illness.
What helps
- ✓Plan activities for the times when your energy is highest — usually the morning.
- ✓A short rest (20–30 minutes) is more effective than a long daytime sleep, which can disrupt your night.
- ✓Eating regularly, with protein and carbohydrates, supports your energy — do not skip meals.
When to contact your doctor
Extreme fatigue that comes on suddenly, especially with paleness, a fast heartbeat or breathlessness, can point to severe anaemia — tell your medical team straight away.
Full escalation guide →⚡ Pain
Pain in cancer can be caused by the tumor, by the treatment, or by medical procedures. Managing pain is an essential part of your care — you should not have to put up with pain. Doctors have effective tools to control it.
What helps
- ✓Keep a pain diary: intensity (0–10), location, timing, and triggers.
- ✓Do not delay reporting new pain to your doctor — uncontrolled pain is a sign that needs assessment.
- ✓Take your pain-relief medicines exactly as prescribed, not only as needed if they are prescribed regularly.
When to contact your doctor
New, severe or rapidly worsening pain — especially at night or at rest — needs urgent medical assessment. Do not try to manage severe pain on your own.
Full escalation guide →🍃 Loss of appetite
Loss of appetite is caused by the treatment, medicines, stress, or changes to your taste and smell. The goal is not to eat a lot, but to give your body essential energy and nutrients, even in small amounts.
What helps
- ✓Eat at set times, even in very small portions — do not wait to feel hungry.
- ✓Choose calorie-dense foods: nuts, peanut butter, avocado, Greek yogurt.
- ✓Make the most of the moments when you feel better — usually early in the morning.
When to contact your doctor
Weight loss of more than 1–2 kg in a week, or being unable to eat or drink anything for 24 hours — contact your doctor or dietitian.
Full escalation guide →🦷 Mouth sores and oral sensitivity
Oral mucositis (mouth sores) means painful ulcers on the lining of the mouth, caused by chemotherapy or radiotherapy. They appear because the cells lining the mouth regenerate quickly and are affected by the treatment.
What helps
- ✓Rinse your mouth with salt water (¼ teaspoon of salt in 250 ml of water) 3–4 times a day.
- ✓Avoid alcohol, tobacco, acidic juices, and hard or spicy foods.
- ✓Choose soft foods that are cold or at room temperature: purees, puddings, yogurt.
When to contact your doctor
Severe mouth sores that stop you keeping fluids down or swallowing, fever, or signs of infection (pus, spreading redness) — contact your medical team straight away.
Full escalation guide →🌿 Hair loss
Alopecia (hair loss) is caused by chemotherapy drugs that affect rapidly dividing cells, including hair follicles. It usually appears 2–4 weeks after treatment starts and is temporary — hair grows back after treatment.
What helps
- ✓Cutting your hair short or shaving before it falls out can make the transition easier.
- ✓Wigs, scarves and hats are all valid options — choose what makes you feel good.
- ✓Protect your scalp from the sun with a high SPF or by covering it.
When to contact your doctor
Hair loss itself does not need urgent escalation, but severe scalp rashes or intense irritation should be mentioned at your appointment.
Full escalation guide →🌱 Constipation
Constipation is common due to anti-sickness medicines, opioid-based painkillers, not drinking enough, or being less active. It is a manageable side effect, but one that needs attention early on.
What helps
- ✓Drink enough fluids — at least 8 glasses of water a day.
- ✓Fiber-rich foods: fruit, cooked vegetables, whole-grain bread (if tolerated).
- ✓Gentle daily movement — even 10–15 minutes of walking.
When to contact your doctor
No bowel movement for more than 3–4 days, severe abdominal pain, intense bloating, or blood in your stool — contact your doctor straight away.
Full escalation guide →💧 Diarrhoea
Diarrhoea is common during chemotherapy, abdominal radiotherapy, or as an effect of certain medicines. It can quickly lead to dehydration and electrolyte imbalances, so it needs to be managed promptly.
What helps
- ✓Drink plenty of fluids — water, clear soups, oral rehydration solutions (such as Gesol or Pedialyte).
- ✓The BRAT diet: bananas, boiled rice, apple puree, toast — foods that help settle your bowels.
- ✓Avoid dairy, fatty foods, fried foods, and foods high in insoluble fiber.
When to contact your doctor
Severe diarrhoea (more than 4–6 episodes a day), blood or mucus in your stool, fever, or signs of dehydration (dizziness, dark urine) — seek help urgently.
Full escalation guide →✋ Peripheral neuropathy
Chemotherapy-induced peripheral neuropathy shows up as numbness, tingling, burning or weakness in your hands and feet. It happens because certain chemotherapy drugs (taxanes, platinums, vinca alkaloids) damage the peripheral nerves.
What helps
- ✓Protect the affected areas — wear thick socks and gloves in cold weather.
- ✓Avoid extreme temperatures (water that is too hot or too cold).
- ✓Gentle walking and balance exercises, if tolerated.
When to contact your doctor
Severe pain, muscle weakness that affects your walking or daily activities, or a sudden loss of sensation — tell your oncologist straight away.
Full escalation guide →🌙 Sleep problems
Insomnia and sleep problems affect 30–60% of cancer patients. They are caused by anxiety, pain, medicines (steroids), night sweats, or changes to the body clock due to hospital stays.
What helps
- ✓Keep a fixed sleep schedule — going to bed and getting up at the same time, including at weekends.
- ✓Avoid screens (phone, TV) for 1 hour before bed.
- ✓A cool, dark and quiet room improves the quality of your sleep.
When to contact your doctor
Insomnia lasting more than 2–3 weeks that significantly affects your quality of life, or extreme daytime drowsiness, needs medical assessment.
Full escalation guide →⚖️ Weight loss
Unintentional weight loss is common in cancer and can be caused by loss of appetite, a faster metabolism, or poor absorption of nutrients. Keeping your weight up matters for tolerating treatment and for recovery.
What helps
- ✓Increase calorie density without increasing volume: add olive oil, butter, nuts or cheese to your food.
- ✓Replace water with whole milk or liquid supplements in your dishes (porridge, pudding, smoothies).
- ✓5–6 small meals a day instead of 3 large ones.
When to contact your doctor
Losing more than 5% of your body weight in 1 month, or 10% in 6 months — ask for an urgent nutritional assessment and a discussion with your oncologist.
Full escalation guide →Other useful sections
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