Undergoing a cancer genetic testing pathway and receiving results regarding a personal or familial cancer predisposition can generate substantial, multifaceted psycho-emotional distress for patients. While professional psychological support is strongly recommended in clinical guidelines, very few studies have formally quantified its actual contribution to the longitudinal psycho-emotional experiences of patients within real-world clinical practices. The primary objective of the PsyOncoGen study is to describe the longitudinal psycho-emotional trajectories of patients within the routine care pathway. It evaluates the clinical impact of psychological support by observing the natural outcomes of patients who choose to accept this systematically offered service versus those who choose to decline it. The study will follow 220 adult patients across two natural cohorts determined solely by patient choice: 110 patients utilising the clinical psychological support and 110 patients declining it.