Cancer of Unknown Primary
Cancer of unknown primary is diagnosed when cancer cells are found but the place where the cancer began remains unknown. The biopsy pattern and molecular features help guide care.
Common signs and symptoms
Having one or more of these symptoms does not mean you have cancer. New, unexplained or persistent changes should be assessed.
- symptoms depend on the organs involved
- a persistent lump or swollen lymph node
- unexplained pain or weight loss
- fluid build up, breathlessness or altered bowel habits
Risk factors
A risk factor changes probability; it does not predict who will or will not develop cancer.
- risk cannot be described as one list because this is a group of cancers
- tobacco, infection and other exposures may be relevant depending on the biopsy pattern
Screening and early detection
There is no screening test specifically for cancer of unknown primary.
How it is investigated and diagnosed
Diagnosis includes biopsy review, imaging, blood tests and selected endoscopic or molecular tests, while avoiding investigations unlikely to change management.
A biopsy or specialist test is usually needed to confirm the diagnosis and exact cancer type. Your healthcare team will explain which tests are appropriate.
Common treatment approaches
Treatment is individual and depends on the cancer subtype, stage, test results, general health and the patient’s priorities.
- treatment directed by the most likely tissue of origin
- chemotherapy, targeted therapy or immunotherapy
- radiotherapy or surgery in selected cases
- symptom and palliative care
Only a qualified treating team can recommend a treatment plan.
Questions to ask your healthcare professional
- What exact cancer type and subtype has been found?
- What stage is it, and which tests established the stage?
- What are my treatment options, expected benefits and possible side effects?
- Should biomarker, genetic or inherited risk testing be considered?
- Who should I contact if my symptoms change or I need urgent help?
When to seek urgent help
Seek urgent help for severe breathlessness, uncontrolled pain, confusion, heavy bleeding or sudden weakness.
If someone is in immediate danger, contact emergency services or go to the nearest emergency department. CFC is not an emergency medical service.
Reliable medical sources
This guide was medically reviewed against current public information from the following authoritative organisations:
This page provides general information only. It cannot diagnose cancer, recommend treatment or replace advice from a qualified healthcare professional who knows your circumstances.