Understanding / Info
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.
Read everything about NauseaWhen to seek help
Nausea lasting more than 24 hours, repeated vomiting that stops you keeping fluids down, or rapid weight loss need urgent medical contact.
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.
Read everything about FatigueWhen to seek help
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.
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.
Read everything about PainWhen to seek help
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.
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.
Read everything about Loss of appetiteWhen to seek help
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.
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.
Read everything about Mouth sores and oral sensitivityWhen to seek help
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.
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.
Read everything about Hair lossWhen to seek help
Hair loss itself does not need urgent escalation, but severe scalp rashes or intense irritation should be mentioned at your appointment.
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.
Read everything about ConstipationWhen to seek help
No bowel movement for more than 3–4 days, severe abdominal pain, intense bloating, or blood in your stool — contact your doctor straight away.
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.
Read everything about DiarrhoeaWhen to seek help
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.
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.
Read everything about Peripheral neuropathyWhen to seek help
Severe pain, muscle weakness that affects your walking or daily activities, or a sudden loss of sensation — tell your oncologist straight away.
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.
Read everything about Sleep problemsWhen to seek help
Insomnia lasting more than 2–3 weeks that significantly affects your quality of life, or extreme daytime drowsiness, needs medical assessment.
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.
Read everything about Weight lossWhen to seek help
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.
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