Prediction of True Oligo-metastatic Disease.

In recent years, the scientific community has recognized the need to differentiate between poly- and oligo-metastatic disease (OMD) in oncology due to their distinct clinical and biological behavior. The definition of "true" and good-prognosis OMD is necessarily retrospective, as many patients initially considered oligo-metastatic develop poly-metastatic disease within one year. The PREDICTION study is a prospective, observational, and monocentric investigation. The study has two primary objectives. The first one is descriptive and aims to determine the prevalence of specific biological characteristics in OMD derived from gastrointestinal tract neoplasms (colon, stomach, biliary tract, exocrine glands of the digestive tract). These biological characteristics include genetic landscape and T lymphocyte infiltrate of the primary tumor and/or metastases. Genetic assessment will be done on formalin-fixed paraffin-embedded (FFPE) tissues or liquid biopsies with the Oncomine Solid Tumour DNA kit (Thermo Fisher Scientific, Waltham, MA, USA). Data analysis will be performed using the Torrent Suite Software v5.0 (Thermo Fisher Scientific). The analysis of T lymphocytes will be conducted through immunohistochemistry (IHC) in primary and or metastatic tissues (if available). The second co-primary objective aims to identify OMD through the prognostic effect of a score designed ad hoc. It is tested in a single pathology, namely in patients with metastatic colorectal cancer. A score is constructed based on the following characteristics, with possession of all characteristics (3+) constituting the full score: a primitive/metastasis genetic concordance \>80% = 1 point; high T-lymphocyte infiltration GRZB+ (\>10 cells/mm2) in the primary tumor and/or metastases (where tissue is available) = 1 point; absence of clonal evolution favoring specific key-driver genes = 1 point. The hypothesis is that patients with true OMD (score 3+) have a significantly lower rate of progression at one ye