Professor Christian Marth discusses whether clinicians should continue to follow-up ovarian cancer patients using the CA-125 tumour marker. A recent study has shown that early treatment in response to a rise in this tumour marker does not increase patient survival; however the patients in this study did not undergo surgery, which is known to increase survival. Prof Marth talks about the reliability of this marker, and explains the progress that has been made using treatment with trabectedin and pegylated liposomal doxorubicin to increase the platinum free interval in ovarian cancer patients and subsequently increase overall survival.
IGCS 2010, 23-26 October, Prague
CA-125 in the follow up of patients with ovarian cancer
Professor Christian Marth – Innsbruck Medical University, Austria
Here at this meeting in Prague you’ve presented regarding the usefulness of follow-up of CA-125. Can you outline?
Recently there has been a major debate whether we should use the tumour marker and the follow-up for ovarian cancer patients because there was an elegant trial performed by the EOTC MRC, Gordon Rustin and Maria van der Burg, telling us that follow-up of ovarian cancer patients by this tumour marker is not helpful. So, early treatment by an early rise of the tumour marker does not increase the survival of ovarian cancer patients. However, in this trial almost nobody had an intervention or surgery and today we know that by performing surgery on recurring patients we can increase survival because we are able to remove the tumour and that’s the crucial point. We have to remove all of the tumour nodules, not only a little of them. So that’s the major point and therefore that’s one of the most important arguments to continue with the follow-up of ovarian cancer patients by the use of the tumour marker CA-125.
So it is a reliable marker or it can be negative and people can still have residual disease?
Yes, that’s possible of course, sometimes the tumour marker is negative. But in almost 70-80% of patients the rise of the tumour marker predicts, in about 4-5 months leading time, the recurrence. So the specificity as well as the sensitivity of this tumour marker is exceptional. Maybe new tumour markers are coming out - AG4 which seems to be very interesting to use as an additional parameter to measure and to predict the recurrence, however, at the moment the best we have is CA-125 and it’s very reliable.
And with regard to treatment of ovarian cancer, there has been a lot at this meeting, can you give us an update?
Of course there are many, many things ranging from biological agents coming out and especially discussion on the role of angiogenesis inhibitors. One point which I would like to focus on that’s very interesting is we know that in a recurrent situation the most important prognostic factor to predict a platinum sensitivity is the duration of the platinum free interval and the recent data telling us that by non-platinum treatment, let’s say pegylated liposomal doxorubicin and trabectedin, you can increase this platinum free interval. So you use another non-platinum treatment to enlarge the platinum free interval and, by the way, these patients then respond again to platinum treatment. The trial has shown that they were able to improve not only progression free survival, the duration of the platinum free interval but they have been able to improve overall survival and that is, of course, in the recurrent situation a very important endpoint.
So these patients which you call partially platinum sensitive would not have any other chemotherapy or they would continue on platinum if they couldn’t have this interval with these other drugs?
All patients with recurrence, finally, unfortunately, will die due to the disease. So now at the moment if we have a reasonable platinum free interval, let’s say at least six months, we will re-challenge them to platinum. If we use another drug combination like pegylated liposomal doxorubicin trabectedin, we can treat with a very good response in-between these patients and then re-challenge them and expose them to platinum. This procedure, up to now, was only a hypothesis, that by enlarging the platinum free interval with a non-platinum containing regimen in the meantime will improve then finally the platinum sensitivity. And that has been shown for the first time and that’s a very interesting point.