Blue and Amber Light Exposure in Patients With Rectal and Pancreatic Cancer

The investigators incorporate appropriate control participants, which include participants who are matched for stage and age and who undergo neoadjuvant chemoradiation and/or surgery but who are not exposed to modulation of their environmental light. There are no deviations from the standard of care for these patients. They will be receiving care identical to that had they not been involved in this study. The only alteration is that some participants will be exposed additionally to either blue or amber light. The investigators use commercially available seasonal affective disorder (SAD) lights that are already approved for therapeutic human use. These lights are small and portable and approved for use for seasonal affective disorder (SAD). The investigators have used them in other human trials and have not identified any adverse or unexpected events. The participants will be asked to have 10 mL of blood drawn for research purposes at 4 time points to assess for markers of the inflammatory response and circadian clock activation. Additionally, they will be asked to complete surveys at 3 time points to assess for quality-of-life measures. They will be asked to wear a small light sensor and a heart rate variability monitor for 7 days to measure the adequacy of light exposure and physiologic response to the exposure, respectively. In the participants who undergo definitive operative resection (e.g., Whipple (pancreaticoduodenectomy) procedure, mesorectal proctectomy), we will analyze a sample of the resected specimen. The investigators will obtain this sample only after complete pathological examination and reporting in accordance with best practices of care. Thus, the sample being acquired for research purposes is discarded biological tissue and no additional sampling is performed. In fact, there are absolutely no deviations or interference with the processes of delivering care.