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Managing Symptoms of Unknown Primary Cancer

Page last updated: November 2025

The information on this webpage was adapted from Understanding Cancer of Unknown Primary - A guide for people with cancer, their families and friends (2024 edition). This webpage was last updated in November 2025.

Expert content reviewers:

This information was developed based on international clinical practice guidelines. All updated content has been clinically reviewed by:

Prof Chris Karapetis, Network Clinical Director (Cancer Services), Southern Adelaide Local Health Network, Head, Department of Medical Oncology, and Director, Clinical Research in Medical Oncology, Flinders Medical Centre and Flinders University, SA.

This edition is based on the previous edition, which was reviewed by the following panel:

Prof Chris Karapetis (see above)
Dr Amey Aurangabadkar, Radiologist, Illawarra Radiology Group, NSW
Clare Brophy, Consumer
Prof Katherine Clark, Clinical Director of Palliative Care, NSLHD Supportive and Palliative Care Network, Northern Sydney Cancer Centre, Royal North Shore Hospital, NSW
Prof Wendy Cooper, Senior Staff Specialist, Tissue Pathology and Diagnostic Oncology, NSW Health Pathology, Royal Prince Alfred Hospital, NSW
A/Prof Richard Gallagher, Head and Neck Surgeon, Director of Cancer Services and Head and Neck Cancer Services, St Vincent’s Health Network, NSW
Dr Chloe Georgiou, Oncology Research Fellow, Australian Rare Cancer Portal, and Oncology Trials Fellow, Bendigo Health Cancer Centre, VIC
Dr Susan Harden, Radiation Oncologist, Peter MacCallum Cancer Centre, VIC
Justin Hargreaves, Medical Oncology Nurse Practitioner, Bendigo Health Cancer Centre, VIC
Dr Laura Kirsten, Principal Clinical Psychologist, Nepean Cancer Care Centre, NSW
Prof Linda Mileshkin, Medical Oncologist, Peter MacCallum Cancer Centre, VIC
Caitriona Nienaber, 13 11 20 Consultant, Cancer Council WA

Symptoms and side effects vary from person to person – you may have none or only a few. This section describes the most common symptoms and side effects experienced during treatment for CUP.

You may experience others not mentioned here. Talk to your treatment team about ways to manage any symptoms and side effects you have.

Your guide to best cancer care

A lot can happen in a hurry when you’re diagnosed with cancer. The guide to best cancer care for liver cancer can help you make sense of what should happen.

It will help you with what questions to ask your health professionals to make sure you receive the best care at every step.

Read the guide

Pain

Many people with cancer worry that they will be in pain. Not everyone will have pain, and those who do may find it comes and goes. Pain is affected by the location of the cancer and its size.

Ways to relieve pain include:

pain medicines, such as paracetamol, ibuprofen and other non-steroidal anti-inflammatory drugs, and opioids (e.g. oxycodone, morphine)
medicines that are normally used for other conditions, such as antidepressants and anticonvulsants (known as adjuvant analgesics)
procedures to block pain signals (e.g. nerve blocks or spinal injections)
therapies, such as massage, meditation, relaxation, hypnotherapy, exercise and physical therapy
psychological therapies that can change the way you think about and respond to pain
cancer treatments used palliatively.

Often a combination of methods is needed and it may take time to find the right pain relief. If one method doesn’t work, you can try something else. Be sure to tell your doctor and pharmacist of all medicines you take.

“During the treatment, I had pins and needles in my hands and in my feet. Walking just got to be almost impossible because I couldn’t quite walk properly at all.” Phil

Using cancer treatments to control pain

Chemotherapy, radiation therapy and surgery are common cancer treatments. They can sometimes be used palliatively to reduce pain by helping to remove its cause.

Radiation therapy

This treatment can be used to relieve many types of pain. The most common form of radiation therapy for pain is external beam radiation therapy.

If cancer has spread to many places in the bone and is causing pain, you may have another form of radiation therapy.

Cancer drug therapies

In some cases, chemotherapy, hormone therapy, targeted therapy and immunotherapy can shrink a tumour that is pressing on nerves or organs and causing pain.

Surgery

Some people have an operation to remove part or all of a tumour.

Surgery can also be used to treat a serious condition such as a bowel blockage (obstruction) that is causing pain, or to reduce the size of a cancer and improve how well chemotherapy and radiation therapy work.

Pain management experts

Your GP or oncologist may be able to suggest effective medicine, but if you are still uncomfortable, ask to see a palliative care specialist.

Good pain control is one of the major ways a specialist palliative care team can help. How and where the pain is felt, and how it affects your life, may change.

Regular check-ups with pain management experts can help keep the pain under control.

Fatigue

For many people, feeling tired and lacking energy can be the most difficult symptom to manage. It can be very frustrating if other people don’t understand how you’re feeling.

Fatigue can be caused by a range of things, such as:

the cancer itself or cancer treatments
low levels of red blood cells (anaemia) or high levels of calcium in the blood (hypercalcaemia)
drugs such as pain medicines, antidepressants and sedatives
infection
loss of weight and muscle tone
anxiety or depression
lack of sleep
poorly managed pain.

Tips for managing fatigue

Pace yourself. Spread your activities throughout the day and take rest periods in between.
Try to do gentle exercise. Research shows this reduces tiredness and preserves muscle strength. Even walking to the letterbox or getting up for meals can help.
Speak to an occupational therapist about ways to conserve energy.
Have a short nap (no more than 30 minutes) during the day. This can refresh you without making it hard to sleep well at night.
Talk to your doctor if you often feel anxious or sad, or if you are having trouble sleeping at night.

Learn more

Nausea

Feeling sick in the stomach (nauseated) is an unpleasant symptom that may be caused by the cancer itself. Nausea can also be a side effect of some types of chemotherapy, but anti-nausea medicines can often prevent or manage this.

Other causes of nausea include:

treatment with radiation therapy
stress or anxiety
too much or too little of a mineral in the blood (e.g. calcium)
drugs used to control other symptoms (e.g. morphine for pain)
the kidneys not working properly
a bowel blockage (obstruction) or constipation
increased pressure around the brain as a result of cancer in the brain or cancer affecting the flow of fluid around the brain and spinal cord.

Tips for easing nausea

Eat small meals as often as you can.
Eat cold foods, such as sandwiches, stewed fruit, salads or jelly.
Have food or drink that contains ginger, such as ginger ale, ginger tea or ginger cake.
Talk to your doctor or nurse about anti-nausea drugs or treatments that can help relieve constipation.
Try to reduce stress by using meditation or relaxation techniques. Listen to our Finding Calm During Cancer podcast.
Avoid strong odours and cooking smells.
Listen to our podcast episode “ Appetite Loss and Nausea”.

Loss of appetite

Not feeling like eating is a common problem faced by people with CUP. This may be caused by the cancer itself or side effects of treatment. You may not enjoy the way food tastes or smells, or you may be worried about the diagnosis and treatment.

You might also not want to eat much if you are feeling sick (nauseated) or have a sore mouth or oral thrush infection. These problems can often be managed, so let your treatment team know.

You may go through periods of having no appetite. These may last a few days or weeks, or be ongoing. During these periods, it may help to have liquid meal substitutes. These are high-kilojoule drinks containing some of the major nutrients needed by your body. Drinking these may help keep your energy levels up during periods when your appetite is poor.

Tips for when you don't feel like eating

Have small meals and snacks frequently throughout the day.
Use small dishes so food isn’t “lost” on the plate (e.g. serve soup in a cup).
Use lemon juice, fresh herbs, ginger, garlic or honey to add more interesting flavours to food.
Sip fluids throughout the day. Add ice-cream, yoghurt or fruit to drinks to increase the kilojoules.
Choose full-fat foods over low-fat, light or diet versions.
If you have a sore mouth, eat soft food, such as scrambled eggs or stewed fruit.
Ask your dietitian or doctor to recommend the right nutritional supplement for you to help slow weight loss and maintain your muscle strength.

Nutrition and Cancer

Breathlessness

Some people with CUP experience shortness of breath. Causes include:

fluid surrounding the lungs (pleural effusion)
an infection in the lungs
a blood clot in the lungs (pulmonary embolism)
pressure from the cancer itself or from a swollen abdomen
anaemia (low levels of red blood cells).

Treatment will depend on the cause. You may need fluid drained from the chest (pleural tap) or medicine for an infection or other lung problem. A low-dose opioid medicine is sometimes prescribed.

Feeling short of breath may make you feel anxious, which can make the breathlessness worse. Your doctor or a psychologist can help you find ways to manage any anxiety.

Tips to help your breathing

Use a battery-operated handheld fan or open a window to increase airflow near your face.
Sit up straight to ease your breathing or lean forward on a table with an arm crossed over a pillow. Try sleeping in a more upright position.
Try relaxation or breathing techniques to see if they help. A physiotherapist or psychologist can teach you these techniques. You can also try listening to recorded meditation or relaxation exercises.
Ask someone else to breathe in time with you so you can focus on slowing your breath to their pace.
Listen to our podcast episode “ Managing Breathlessness when Cancer Is Advanced”.

Get support

Many people feel shocked and upset when told they have cancer. It can be even more distressing if the cancer has spread and the original (primary) site cannot be found.

Cancer Council's experienced nurses can help you connect with other people who are living with advanced cancer, and provide you with information about the emotional and practical aspects of living with CUP.

Contact cancer support