Radiation Oncology Strategies for Patients with Poor Pulmonary Function in Non-small Cell Lung Carcinoma

Abstract

Lung cancer is the leading cause of cancer deaths worldwide. Recently, there is an emerging interest on lung cancer screening which can increase the incidence of lung cancer among the population in the coming. There was 20% reduction in mortality from lung cancer in the National Lung Screening Trial (NLST) with the use of low-dose computed tomography. NLST criteria included people between ages 55-74 years, ≥30 pack-years of smoking or <15 years since cession of smoking. Patients with early stage disease and young age, good performance status and pulmonary function tests are treated with curative intent including either surgery or combined treatment modalities, concurrent chemo-radiation therapy. Treatment of choice for medically inoperable group of patients is definitive radiation therapy (RT). Patients with poor pulmonary function (PF) are considered a contraindication to definitive RT. We discuss the role of RT and importance of dose escalation to achieve improved local control rates among patients with different stages of non-small cell lung carcinoma (NSCLC) with poor PF. Till date, there are no clinical practice guidelines or randomized prospective phase III studies to treat this subset of high-risk patients with RT dose escalation using advanced RT techniques like intensity modulation radiation therapy, volumetric modulated arc therapy (IMRT, VMAT). Also, there is limited evidence on the use of newer chemotherapy regimens with advanced RT techniques for NSCLC patients with poor PF except for retrospective data or phase I/II studies. Different tools to estimate and measure radiation pneumonitis (RP) along with the review of the published data on RP was done. Impact of newer RT techniques along with adaptive RT using mid-course PET scans for RT planning using photons and protons are also addressed.