Effect of Radiotherapy Variables on Circulating Effectors of Immune Response and Local Microbiome

The study prospectively collects blood specimens for assessment of peripheral immune mediators in 4 distinct clinical settings of standard radiotherapy. In addition to collecting blood specimens, the study will also collect physical and dosimetric information of treatment such as total dose, number of treatments, and/or size of the radiation targe, as these will allow the investigators to study the impact of radiation variables on the immune system. Stool specimens will be collected at baseline, end of radiation therapy and during the follow up visit to detect microbiome changes associated with different radiation treatment at various time points. Humans are colonized by commensal bacteria, which outnumber human cells. These normal bacteria colonize mucosal surfaces and play a critical role in immunity. It is hypothesized that the underlying microbiota may also undergo changes in composition that correspond to the regimen of radiation that is utilized. By collecting stool specimens, investigators will be able to study microbial changes and how these changes correlate with alteration in immune mediators (i.e., lymphocytes, cytokines) present in blood samples before, during and after radiation; and explore the association between these parameters and type of radiation received.