Bone marrow sparing RT in era of immunotherapy

Abstract

Recent advances in the field of immunotherapy have changed the perception of cancer treatment to complex model with host immunity in the spotlight. Potential synergy of immunotherapy drugs [aiming cytotoxic T cell antigen 4 (CTLA-4) or programmed cell death-1/ligand (PD-1/PD-L1)] and radiotherapy (RT) have established basis for ongo­ing clinical trials testing combined treatment. It was shown that complete blood cell counts (CBC) parameters may correlate with cancer survival, toxicity and outcomes of treatment. Therefore, reduction of hematologic toxicity of cancer treatment may gain in significance. Modern dose delivery techniques compromise dose reduction in critical organs (like bone marrow — BM) with adequate irradiation of target volumes. In addition, usage of modern imaging like positron emission tomography (PET), magnetic resonance imaging (MRI) allows to divide the volume of BM to active and inactive one.

In this review, we discuss the synergy of RT and immunity and techniques of Bone Marrow Sparing RT (BMS-RT).