Short Neoadjuvant Hemithoracic IMRT for MPM

Overview

Malignant pleural mesotheliomas (MPMs) are tumours associated with asbestos exposure involving the tissue lining surrounding the lung. Radiation therapy (RT) dramatically reduces the risk of tumour recurrence within the irradiated area (\>90%). But patients continue to succumb to MPMs due to the tumour spreading outside the chest cavity. This may be due to tumour cells inadvertently contaminating areas outside the chest cavity during surgery. The study will look at whether giving a short intense course of chest radiation just prior to surgery will sterilized these tumour cells and thus, avoid or reduce contamination of the areas outside the chest cavity. The investigators hypothesize that short neoadjuvant (pre-operative) hemithoracic RT, followed by immediate planned extrapleural pneumonectomy (EPP) (+/- adjuvant chemotherapy) will reduce the risk of intra-operative seeding and reduce the incidence of distant metastatic disease.

The study is a phase I/II prospective single cohort clinical feasibility study. 100 patients with early stage resectable malignant pleural mesothelioma will be enrolled into the study. Patients will have a baseline PET scan. Patients on the study will receive IMRT for approximately 1 week of 5 daily treatments. 1 week post-RT, they will proceed with an extrapleural pneumonectomy. If the mediastinal lymph nodes that are removed during surgery are positive for tumour cells, 3 cycles of chemotherapy, consisting of raltitrexed and cisplatin OR Pemetrexed and cisplatin, will be given 6-12 weeks post-surgery. Before and during treatment, side effects will be assessed. After treatment, follow up visits will be conducted every 1 to 2 months for the first year, and every 3 months for the second year. At each visit, a history and physical examination will be performed and ECOG performance status will be assessed. Routine tests will include CBC, liver profile, creatinine and chest x-ray. CT thorax and abdomen will be done at 3, 6, 12, 18, and 24 months. Additional test may be done at the discretion of the oncologist if the patient becomes symptomatic. The study will evaluate the feasibility and safety of short pre-operative RT, and may help confirm the intraoperative seeding hypothesis. Preoperative RT may also reduce the risk of both local and distant spread and, ultimately, improve overall survival. By shortening overall treatment time, it may also improve patient compliance and convenience. We may be able to give chemotherapy only to patients that are at highest risk and avoid it in others.