CA 72-4 test: what it shows and how the result is read

CA 72-4 (a tumour-associated glycoprotein) is a protein whose level in the blood can rise when certain tumour cells are present in the body, most often ones related to stomach cancer, and also with some mucinous ovarian or pancreatic tumours. Tumour marker tests in general are used not to make a primary diagnosis but after a diagnosis has been made — to follow how the body is responding to treatment, whether the tumour is not growing, whether it has not come back after treatment, and to assess the stage of the disease. Some such tests are also used to check people at high risk or with symptoms. It is important to understand this: a raised marker level shows a higher probability of cancer, but does not by itself confirm cancer, because some conditions that are not cancer (benign, inflammatory) can also raise the concentration of certain tumour markers. In addition, not all tumours produce large amounts of the marker — so a normal result likewise does not rule cancer out entirely. A CA 72-4 result always has to be assessed together with imaging tests, a biopsy and the doctor's assessment.

• To follow the course of treatment after a diagnosis of stomach cancer or a mucinous ovarian tumour — whether the treatment is working
• To check whether the tumour has come back after a course of treatment or an operation
• To help establish the stage of the disease, together with other tests and imaging methods
• Sometimes — as an additional test for people with matching symptoms or a higher risk, together with other tumour markers (for example CEA, CA 19-9)

There is no universally recognised international threshold value in publicly published health organisation guidelines, and different laboratories use different test methods and intervals. You will find the exact reference limit used by your own laboratory on your result report — and it always has to be assessed together with a doctor.

A raised CA 72-4

A raised CA 72-4 is most often seen in stomach cancer or mucinous ovarian tumours, but according to the general information on tumour markers, some conditions that are not cancer (benign, inflammatory) can also raise the amount of certain tumour markers. That is why a single raised result does not by itself confirm a diagnosis — it has to be assessed together with imaging tests and the doctor's assessment.

• Cancers — most often stomach cancer, and also some mucinous-type ovarian or pancreatic tumours
• Benign (non-cancerous) conditions of the digestive tract or the ovaries — it is generally known that some conditions which are not cancer can also raise the concentration of tumour markers
• The stage and size of the disease — larger or more widespread tumours are more often associated with a higher marker level

What to discuss with a doctor

• Discussing the result with a doctor alongside imaging tests (endoscopy, ultrasound, CT) and biopsy findings
• Assessing it together with other tumour markers (for example CEA, CA 19-9, CA 125), which can help to assess the situation more precisely
• If the test is being done to follow the course of treatment — comparing it with earlier results, not with a single number
• Checking whether there was an acute illness or inflammation at the time that could have temporarily affected the result

Related pages: CA 15-3, AFP, how to prepare for a blood test and how to read blood test results.