Background: Drug-related complications have been associated with adverse outcomes in older adults with cancer. This pilot interventional study aimed to assess the feasibility of introducing an inpatient multidisciplinary (MDT) comprehensive medication assessment focussing on the specific needs of older adults with cancer, in addition to standard hospital medication review and reconciliation. Methods: Patients≥70 years with a solid tumour diagnosis, admitted under the medical oncology service, were discussed at a weekly MDT meeting involving geriatric oncology physicians, nurses and pharmacists. Relevant data including age, cancer type and stage, Rockwood clinical frailty scale, comorbidities, medications on admission and initiated during hospitalisation, systemic anti-cancer therapy (SACT), falls history, cognitive screening, and laboratory parameters were prospectively collected. An MDT medication review was conducted including SACT toxicity assessment, drug-drug interactions (DDI), potentially inappropriate medication (PIM) assessment using STOPP/START criteria, and anticholinergic burden (ACB) scoring. A summary of medication review findings and recommendations was provided to the primary inpatient team to support medication optimisation. Results: Sixty patients were included over a 4 month period, with a median age of 76.5 years (range 65-88). Most patients had lung cancer (36.7%), 80% had stage IV disease. Twenty-five patients (42%) were moderately or severely frail. Most patients (61.7%) were on systemic anti-cancer therapy (SACT). Seven patients (11.7%) had a fall in the previous 3 months and 15 patients (25%) experienced acute confusion during the hospitalisation. ADEs were identified in 26 patients (43%), PIMs in 33 (55%), excessive ACB in 43 (72%) and DDIs in 53 (88%). MDT medication optimisation recommendations were made in 59 patients (98%) in addition to standard of care review. Based on review findings, medication interventions included recommendations to deprescribe, start drug, amend drug dose, route or frequency, perform additional laboratory monitoring, and SACT-specific recommendations (Table 1). Conclusions: Implementing an interprofessional geriatric oncology MDT approach to medication review in hospitalised older adults with cancer can result in additional medication recommendations alongside standard of care.