Microbiota, Inflammatory Environment, Clinical and Radiomic Features as Predictors of Normal Tissue Response in Radiotherapy for Prostate and Head-and-neck Cancer

The main idea behind MICRO-LEARNER is to provide new insights about the response of healthy tissues to radiation by using information from the micro-environment obtained by biological measurements and imaging. This new knowledge will be included in current available predictive models of radio-induced toxicity, thus allowing to add unique biological characteristics of patients to dosimetry and treatment/clinical related variables.

MICRO-LEARNER focuses on prostate cancer (PCa) and head-and-neck cancer (HNCa). For both cancers, radiotherapy is effectively used as curative treatment, in single modality or within a multidisciplinary approach including surgery (PCa) and/or chemotherapy (HNCa). Prediction and reduction of radio-induced side effects are becoming a priority: for PCa, high survival rates should be accompanied by a very low rate of moderate/severe toxicities; for HNCa, there is the need to tailor radiation dose according to disease recurrence risk profile. The shared aim of both cancers is to balance the improvement in outcome with a well-tolerated toxicity profile.

Recent research indicates that the intestinal/salivary bacteria are strongly suspected of being very important in mediating the response to inflammation and lesions. Although their balance deeply changes during radiotherapy, studies done so far in the field of the microbiota-host relationship in radiotherapy have not addressed their role in insurgence of radiation toxicity.

In this study, the investigators will assess how microbial populations evolve and how this influences the host and radiation induced toxicity in a significant number of patients. Moreover, the individual response at the tissue microstructure level, through analysis of images with advanced bioengineering techniques, will be determined.

Results from this research, besides suggesting new ways to predict patients at risk of relevant side-effects, may also suggest possible treatments to change the baseline microbiota of patients at high risk or to modify it during therapy, in order to mitigate toxicity. Understanding the microbiota-radiotherapy interaction may thus lead to novel, effective and inexpensive ways of assessing and managing complications of cancer treatment.