MARS Trial Update – Surgery a success?

The MARS trial is the first randomised trial to address the role of radical surgery such as extrapleural pneumonectomy or EPP when treating those who suffer with incurable asbestos related mesothelioma.

EPP is a surgical procedure which involves the removal of part of the lining of the lung (the pleura), part of the pericardium (the lining of the heart) and part of the diaphragm as well as the section of diseased lung itself.

The trial encompasses Trimodality therapy which involves induction chemotherapy where appropriate, followed by EPP with radical radiotherapy being provided after surgery.

Before the MARS trial, the available knowledge on patients’ outcome was from those who had received a combination of chemotherapy, surgery and radiotherapy, it was impossible to uncover whether the surgery on its own was of real benefit or not.

Those diagnosed with pleural mesothelioma and considered suitable for the above treatments gave consent to partake in the trial and underwent chemotherapy treatment. The results of which were then reviewed by the MARS team of medical specialists.

The aims and objectives of the trial was to uncover the effect on survival rates in those who suffer with mesothelioma and a sample size of 670 patients in groups who either did or did not go on to undergo EPP after undergoing the induction course of chemotherapy. It was hoped that the data would prove invaluable in the assessment of benefits of different forms of treatment.

The trial assessed post surgery mortality rates and considered the proportion of randomised patients proceeding to allocated treatment. Another important study involved assessing the effect of the treatment on the patients’ quality of life.

The Guy’s and St Thomas Hospital London, University Hospital in Leicester and the Cookridge Hospital in Leeds are all engaging in the trial from a surgical perspective as well as reviewing the affects of other forms of treatment.

Between October of 2005 and November of 2008, 112 patients were registered for the trial, with 50 having been allocated to undergo one or the other treatment on a split of 24 who underwent EEP surgery, with the remaining 26 not undergoing the radical operative procedure.

The results of the study were illuminating.

  • The data showed that as a group the non-surgical patients actually lived longer on average than those who had undergone EPP.
  • Sufferers who underwent the surgery experienced more complications than those who had other forms of treatment.
  • Patients in the surgery group’s quality of life, was more adversely affected, than those in the non-surgical group.

It was also uncovered that;

  • Just under half of the registered patients remained fit enough for surgery and were to be randomly selected for one or other treatment.
  • In around a third of the cases for referred EPP, the operations could not go ahead for a variety of reasons.

The question is therefore, what do the findings actually show?

What is clear is that all forms of cancer treatment carry with them risks and uncertainties which can result in adverse side effects and further harm to patients. The focus must be on ensuring that the benefits of different treatments outweigh the negatives.

On balance, the most recent MARS findings show that EPP offered no benefit to those who engaged in the trial which whilst initially seen as a disappointment, does allow treating medical teams to advise their patients further in when considering the most important issue of available treatments.