Risk and impact of radiation related lymphopenia in lung cancer: A systematic review and meta-analysis.

Abstract Background Despite the modern advances in treatment techniques, the survival of locally advanced lung cancer patients continues to remain poor. Circulating lymphocytes have an important role to play in local immune response to RT as well as immune checkpoint inhibitors, and radiation related lymphopenia has been associated with inferior survival in various tumors. Methods We undertook this systematic review and meta-analysis to evaluate the literature on risk and impact of lymphopenia in thoracic tumors. A systematic methodology search of the PubMed, Embase and Cochrane library was performed and eligible studies selected based on pre-defined inclusion and exclusion criteria. Review Manager Version 5.4.1 was used for the meta-analysis. Results Fourteen studies were included in the final systematic review and 10 in the quantitative analysis. Overall mean incidence of severe lymphopenia (absolute lymphocyte count Conclusion Radiation related lymphopenia is associated with increased hazard of progression and death in lung cancer. Minimizing the lung and heart dose, especially in patients with concurrent other risk factors can reduce lymphopenia and potentially improve treatment outcomes in these patients.