Predictors of Normal Tissue Response From the Microenvironment in Radiotherapy for Prostate and Head-and-neck Cancer

\*\*Prospective Clinical Trial: discovery population\*\* 130 PCa and 130 HNCa consecutive patients will be enrolled in 18 months. All patients will receive radiotherapy at radical curative doses at the National Cancer Institute in Milan, and follow-up visits at the same centre. Detailed pre-treatment evaluation will include: recording of demographic features, clinical history, comorbidities and habits, evaluation of normal tissue functioning by the health practitioner (CTCAE scoring system), evaluation of quality of life and normal tissue functioning through validated patient reported outcome (PROs) questionnaires, evaluation of organ functioning by instrumental measures (i.e. baseline swallowing screening with flexible endoscopic evaluation of swallowing - FEES - and unstimulated salivary flow for HNCa patients), biochemical examinations, gut (PCa)/salivary (HNCa) microbiome measurement, determination of baseline level of plasma/salivary inflammatory markers, baseline multi-parametric magnetic resonance imaging (MRI). Patients will receive radiotherapy and possible adjuvant (hormone or chemo) therapies as foreseen by international guidelines. In this aspect the here proposed trial is an observational study, no modification to standard regimens is considered. Radiotherapy is performed with 6 MV photon beams delivered with Volumetric Modulated arc Therapy (VMAT) technique at conventional fractionations. Evaluation during treatment will include weekly assessment of toxicity, as measured by the clinician (according to CTCAE v 4.0) and by PROs and biochemical measurements, and evaluation of inflammatory markers (plasmatic and salivary cytokines) after a dose of 20 Gy. For a subpopulation of 60 oropharyngeal cancer patients treated with definitive radiotherapy +/- chemotherapy an additional MRI study during the second week of treatment is foreseen. Assessment at the end of radiotherapy will include evaluation of toxicity by the clinician and by PROs, FEES and unstimulated salivary flow for HNCa patients, biochemical examinations, gut/salivary microbiome measurement. Evaluation at 3, 6 and 12 months will include: evaluation of toxicity by the clinician and by PROs, FEES and unstimulated salivary flow for HNCa patients and biochemical examinations. Minimum follow-up is set to 12 months for the specific purpose of evaluation of acute and mid-term toxicity, which are the endpoints considered in this project. Nevertheless, follow-up will continue until 3 years after the end of radiotherapy (beyond the end of the project) in order to allow evaluation of incidence, prevalence and patterns of late side-effects, as well as for survival outcome assessment. After 12 months, follow-up will be performed every 6 months and limited to assessment of toxicity by the clinician and by PROs. Follow-up MRI studies will be performed at 3, 12 and 24 months for HNCa patients and at 12 months for PCa patients. \*\*Prospective Clinical Trial: validation population\*\* 70 PCa and 70 HNCa consecutive patients will be enrolled in 12 months, starting immediately after the end of enrolment of the discovering population. The specific aim of this second phase is validation of results on microbiota, specifically on association between selected baseline microbiota profiles and the risk of acute toxicity (for the purpose of this project) and for mid-term/late toxicity (beyond this projects). This result should be the more significant from the clinical point of view, allowing development of a therapeutic algorithm to be used before treatment and permitting introduction ways of changing the make-up of gut/salivary bacteria in patients at high risk of toxicity. Baseline assessment, treatment and follow-up evaluation of toxicity by the clinician and by PROs will follow the scheme described for the developing population. Microbioma measurement will be only performed at baseline, due to the higher clinical interest in having a test determining patient radiosensitivity before treatment. Imaging and assessment of inflammatory marker levels will not be accomplished in the validation population.