Pain in Malignant Pleural Mesothelioma
The pain which patients get with Malignant Pleural Mesothelioma (MPM) can be very difficult to control with standard painkillers and very often people remain uncomfortable despite being on a combination of tablets and patches. Treatment with high energy x-ray beams (radiotherapy) to areas of discomfort has been used for many years to help relieve pain in these patients, despite a lack of strong evidence to show that this works well or to indicate which dose of radiotherapy is best.
The SYSTEMS Study
The SYSTEMS study was a clinical trial set up to test whether a standard dose of radiotherapy is helpful for pain in MPM. ‘SYSTEMS’ stands for ‘Symptoms Study of radiotherapy in Mesothelioma’. This study recruited 40 patients from 3 cancer centres over 18 months and gave a standard dose of radiotherapy over 1 week to areas where the patients had most pain. Five weeks later, one third of patients reported a significant improvement in their pain score, with very few side effects.
In SYSTEMS-2, we are comparing the standard dose of radiotherapy (given in SYSTEMS) with a bigger dose given over 2 weeks. The reason for doing this is because we believe that the bigger dose of radiotherapy may be more effective in controlling pain, but because no-one has looked at this before, we cannot be sure. Also- because of the way that the radiotherapy is given, we think that a bigger dose of radiotherapy wouldn’t be significantly worse than the lower dose in terms of side effects, but again, we do not know this for sure. The only reasonable and ethical way to decide which dose is best for pain control with acceptable side effects is to compare both side by side in a randomised study. ‘Randomised’ means that patients who take part in the study will be chosen at random by computer to receive one of the two treatment regimes. Neither the doctor nor the patient has any control over which treatment will be selected, but over the course of the trial, 50% of patients will receive the standard dose and 50% will receive the higher dose of radiotherapy.
In addition to assessing pain control, we will be monitoring for any side effects of the radiotherapy as well as the impact on quality of life and overall survival time. Patients will have a CAT scan done 9 weeks after their radiotherapy to determine whether any changes can be seen as a result of the treatment.
Since we will be giving a bigger dose of radiotherapy to some of the patients, we are using more sophisticated methods to plan and deliver the treatments than were used in SYSTEMS. These techniques allow us to carefully control the doses given to ‘normal’ tissues, ensuring that these are kept at a safe level and don’t cause unacceptable side effects.