CLINICAL INTUITION is an Experience-based, Often Unconscious Assessment of a Patient's Resilience and Tolerance. It is INFLUENCED by Clinical Signs, Behavior, Functioning, and Context. While it MAY PREDICT Patient Dropout, it is Difficult to Objectify.

Patient selection for Phase I oncology trials is formally based on protocol-defined inclusion and exclusion criteria. In practice, however, healthcare professionals also take clinical intuition and professional experience into account when assessing suitability. The role of this intuitive judgment is insufficiently described in the literature, even though it may be relevant for preventing early trial discontinuation.

Inclusion Criteria: * Healthcare professionals working within or closely affiliated with the Erasmus MC Phase I team. * Direct involvement in eligibility assessment and recruitment for Phase I oncology studies. * Ability to communicate in Dutch. * Provision of written informed consent. Exclusion Criteria: * No involvement in patient selection in phase I. * Inability or unwillingness to provide consent. * Insufficient availability to participate in an interview.