Is immunotherapy at reduced dose and radiotherapy for older patients with locally advanced non-small lung cancer feasible?-a narrative review by the international geriatric radiotherapy group.

Background and Objective: The standard of care for locally advanced non-small cell lung cancer (NSCLC) is either surgery followed by adjuvant chemotherapy with or without radiotherapy or concurrent chemotherapy and radiotherapy. However, older patients (70 years old or above) with multiple co-morbidities may not be able to tolerate the combined treatment due to its toxicity. Since lung cancer prevalence increases significantly with age, a new algorithm needs to be investigated to allow curative treatment for those with locally advanced disease. Methods: A literature search of the literature was conducted through PubMed and Google Scholar using search terms such as locally advanced NSCLC, older cancer patients, immunotherapy with check point inhibitors (CPI), and image-guided radiotherapy (IGRT). Abstracts were screened, full articles fitting the article topic were reviewed, and duplicated and non-English articles were excluded. Key Content and Findings: Recently, CPI has been introduced and proven effective for selected patients with increased program death ligand 1 (PD-L1) expression (50% or above). A reduced dose for CPI (RDCPI) may be as effective as a full dose and may decrease treatment cost. New radiation technique such as IGRT may also minimize radiotherapy complication through normal lung and cardiac sparing. Conclusions: IGRT and RDCPI may be an innovative option for older patients with locally advanced NSCLC and high PD-L1 expression and needs to be investigated in future prospective studies.