அணு மருத்துவம் & கதிர்வீச்சு சிகிச்சை

Malignant Pleural Mesothelioma: Management and Role of Radiation Therapy

Abstract

Donato V, Dognini J, Arcangeli S, Melis E and Facciolo F

Malignant pleural mesothelioma is a neoplasm derived from the mesothelial surfaces of the pleura. There are tree different mesothelioma types: Epithelioid Mesothelioma; Sarcomatoid; Biphasic /Mixed Mesothelioma. Patients with mesothelioma have a poor prognosis with a median survival ranging from 6 to 18 months depending on the stage of the disease at the time of diagnosis.

Standard Management: For patients with clinical stage I-III and Epithelial or Mixed histology who are considered medically fit, surgery is recommended with extrapleural pnemonectomy (EPP) or pleurectomy/decortication (P/D). Adjuvant radiation therapy is recommended for patients with good performance status: the goal of adjuvant radiotherapy is to improve local control and it is an effective palliative treatment for relief of chest pain associated with mesothelioma. Chemotherapy alone is recommended for those who are not operable, those with clinical stage IV MPM or those with sarcomatoid histology.

Radiotherapy: The target volumes delineation, defined by the radiation oncologist, is crucial because of large and irregularly shaped area at risk, high dose required for local control, the promixity of many structures as ipsilateral kidney, heart, spinal cord, esophagus, controlateral lung and the ipsilateral lung itself in inoperable cases. Actually sophisticated RT techniques such as IMRT, IGRT, and especially helical-slit IMRT (HT) might become appropriate alternatives for either definitive or palliative treatment for suitable patients based on compatible pulmonary toxicity criteria.

The actual MPM guidelines suggest that the dose of radiation should be based on the purpose of the treatment. So the dose of radiation for adjuvant therapy should be 50-54 Gy with negative margins and 54-60 Gy with microscopic-macroscopic positive margins, in 1.8-2.0 Gy/day. For prophylactic radiation to surgical sites, a total dose of 21 Gy (3 x 7 Gy) is recommended.