Recent reports
Measuring CA125 during follow-up
Professor Gordon Rustin from Mount Vernon Hospital reviews the pros and cons of regular CA125 measurement, which is currently being assessed in a clinical trial. If you would like more information about this trial ask your local oncologist. 28 hospitals around the UK are offering this trial to their patients.
The blood test for CA125 is elevated in over 90% of patients with advanced ovarian cancer. Many patients, however, remain well despite a rising CA125 level for six to 36 months. There is debate around the world as to whether it is in the patient's best interest to have CA125 measured routinely during follow-up.
There are good arguments for regular CA125 tests and equally good ones against. The main reason for measuring CA125 regularly during follow-up is the hope that early detection and treatment of relapsed disease, indicated by rising CA125, would improve overall survival. In addition, hospital admissions for symptoms due to tumour bulk, fluid in the abdomen or blockage of the bowel might also be avoided. However, there is currently no evidence that early treatment based on a raised CA125 in patients without any symptoms improves either survival or symptom control. Many patients and clinicians are reassured by a normal CA125, but this can be misleading: it is possible for patients to have recurrent disease but still have normal CA125 levels.
One disadvantage is the inconvenience of having to go for routine blood tests. Another disadvantage of routine CA125 measurements in follow-up include considerable anxiety among patients receiving regular blood tests. This often results in patients losing sleep prior to the next clinic visit worrying about the result. Such anxiety may even induce what some doctors call CA125 psychosis and others a 'disease in a tube'. Treating relapsed ovarian cancer when patients are symptom free may result in the patient receiving more chemotherapy and with this more treatment related side effects. Treating relapsed ovarian cancer early when patients are symptom-free may result in the patient receiving more chemotherapy during their remaining life and, with this, more treatment-related side effects.
These uncertainties are being addressed in a multi-centre trial, run by the Medical Research Council Clinical Trials Unit in the UK, called MRC OV05 trial (ISRCTN 87786644), and the EORTC (European Organisation for the Treatment of Cancer) in mainland Europe where it is called EORTC 55955. Patients who consent have blood tests for CA125 each time they attend the hospital for follow-up visits. The CA125 result is only sent to the trial organisers; the doctor and patient are not told the result. If the CA125 level is double the upper limit of the local normal range, the patient is randomised (allocation by chance) into one of two groups. In the first group, the patient is offered immediate chemotherapy whilst in the second group the patient continues her usual follow-up until she develops signs or symptoms that suggest relapse of ovarian cancer. The main question of this study is whether survival is affected by earlier or later treatment of relapsed ovarian cancer.
Patients in the study fill in quality of life questionnaires so it should be possible to also compare factors such as emotional wellbeing between the two groups. Over 850 patients have so far entered the study and it will continue for a further three years so that 1400 patients can enter.
Until the results of this trial are available, any survival benefit due to the routine use of CA125 measurements in the follow-up of ovarian cancer patients remain unknown. In several large European centres the majority of patients agree to enter the CA125 follow up trial. We recommend that, for patients not entering the CA125 follow-up trial, CA 125 measurements are only performed when there are symptoms or signs that might indicate disease progression. Many patients are given CA125 pathology request forms and advised to use them only if they have worrying symptoms. However, many patients, particularly in the USA, demand regular CA125 measurements for reassurance purposes, but require counselling about the potential disadvantages.
