Background: Early phase oncology clinical trials have become increasingly complicated in terms of patient selection and trial procedures. Informed consent has been contentious due to potential ethical issues associated with performing experimental research on patients with advanced cancer who lack standard treatment options. Prior research has shown significant gaps in patient understanding regarding the nature and intent of these trials. CONSENT aimed to test whether enhanced informed consent can improve clinical trial comprehension. Methods: We randomized patients eligible to participate in one of four investigator-initiated early phase oncology clinical trials at the Royal Marsden Drug Development Unit to either a control arm or an experimental arm, stratified by age and educational level. The control arm received the full-length trial PIS, followed by electronic or paper administration of the Quality of Informed Consent Questionnaire Parts A (QuIC-A). The experimental arm received the full-length trial PIS, exposure to a two-page study specific aid and 10 online educational videos (both co-designed with patients and clinicians), followed by administration of the QuIC-A. The primary endpoint was the difference in the QuIC-A score between the control and experimental arm. The accrual target was at least 17 evaluable patients per arm to detect an 8-point difference (80% power, alpha 0.05). Results: 23 patients were accrued to the control arm (17 evaluable) and 22 patients (18 evaluable) were accrued to the experimental arm. Patients were evaluable if they had completed the QuIC-A. 38% of the participants were over the age of 65, 91% identified as White, 56% had completed a university degree and 97% spoke English at home. We did not observe a significant improvement in the primary endpoint in evaluable patients – control (QuIC-A - 76.5/100) vs experimental arm (QuIC-A - 77.4/100), p value = 0.39 (one sided, two sample t-test). 20 participants provided feedback on the enhanced consent materials via a study questionnaire –75% found both the 2-page study aid and the videos not at all distressing or uncomfortable and 85% found them either quite useful or very useful. Conclusions: This is the first prospective randomized trial evaluating the impact of communication interventions on informed consent in advanced cancer patients considering early phase oncology clinical trials. The co-designed interventions were deliverable online and were acceptable and useful for patients. We did not demonstrate an improvement in the primary endpoint with a high QuIC-A score observed in the control arm- this could be explained by the study population which was highly educated, White and spoke English at home. Future studies should focus on groups with lower literacy and from culturally and linguistically diverse backgrounds. Clinical trial information: NCT04407676.