PIT: Prophylactic Irradiation of Tracts in Patients With Malignant Pleural Mesothelioma

• Time from randomisation to chest wall tract metastasis [ Time Frame: Weeks ] [ Designated as safety issue: No ]
  Patients will be assessed at regular intervals approximately every 4 weeks by phone and at regular outpatient visits in the first year of follow up for signs of chest wall metastasis
• Position of chest wall tract metastasis recurrence in relation to radiotherapy field in patients randomised to experimental arm (in field/out-of-field) [ Time Frame: Weeks ] [ Designated as safety issue: No ]
  Patients will be assessed at regular intervals approximately every 4 weeks by phone and at regular outpatient visits in the first year of follow up for signs of chest wall metastasis
• Acute and late skin radiotherapy toxicity [ Time Frame: Weeks ] [ Designated as safety issue: Yes ]

  Patient will attend hospital at 6, 12, 26 and 52 weeks post randomisation where toxicity to PIT will be assessed.

  CTCAE v4.0 will be used

• Pain from chest wall tract metastasis [ Time Frame: Weeks ] [ Designated as safety issue: No ]
  Patients will be assessed at regular intervals approximately every 4 weeks by phone and at regular outpatient visits in the first year of follow for pain scoring using a Visual Analogue Scale (VAS)

The PIT (Prophylactic Irradiation of Tracts) trial will determine whether or not PIT radiotherapy is effective in preventing or delaying the onset of chest nodules in patients with Mesothelioma.

Mesothelioma is a rare form of cancer affecting the protective lining that covers many of the body's internal organs. The most commonly affected areas are the lungs and internal chest wall. In the UK over 2300 patients are diagnosed with mesothelioma each year and the numbers are increasing.

As part of the diagnosis and treatment of mesothelioma, patients may undergo a procedure which involves inserting a thin tube into the chest wall enabling an internal examination and for any biopsies or samples of fluid to be taken. These procedures can result in the development of skin lumps or nodules along the tract created by inserting the tube. To try and reduce the risk of these nodules developing in the tract or at the site of the scar, radiotherapy can be given to the chest wall at the site of the tract after the procedure has been performed; this type of radiotherapy is known as prophylactic irradiation of tracts or PIT.

Although many hospitals already give patients this type of radiotherapy treatment to the chest wall we still do not know if the treatment works. This trial has been designed to answer the question about the effectiveness of PIT radiotherapy. If PIT is found to be effective in preventing or delaying the development of these skin nodules then it can be offered to all patients as part of their treatment. However, if we discover that PIT is not effective this will save patients from undergoing ineffective treatment and having to spend time making unnecessary extra visits to hospital

• Experimental: PIT Arm
  Intervention: Radiation: Prophylactic Irradiation of Tracts (PIT)
• No Intervention: No PIT Arm

Inclusion Criteria:

• Either sex, age ≥ 18 years
• Diagnosis of mesothelioma by multi-disciplinary team (MDT). All histological subtypes are eligible for the trial
• ECOG performance status 0-2 (Appendix C)
• Inoperable disease or operable disease in patients unsuitable for surgery as decided by a MDT
• Chest wall intervention with video-assisted thoracoscopy (VATS), open surgical biopsy (mini-thoracotomy), local anaesthetic thoracoscopy or chest drain
• Able to start radiotherapy within 42 days (6 weeks) of the most recent chest wall procedure
• Chest wall intervention scar visible at time of randomisation
• Radiotherapy target volume acceptable by the local radiotherapist
• Patients enrolled on other clinical trials could be considered after discussion with the chief investigators

Exclusion Criteria:

• Patients who underwent a thoracotomy (as large thoracotomy scars may not be adequately covered by this radiotherapy technique)
• Previous radiotherapy to the region of the chest wall intervention site
• Indwelling pleural catheter in-situ at the intervention site
• Patients currently receiving chemotherapy