Abstract Introduction In the UK, up to two-thirds of all cancer patients have at least one comorbidity, with around half having multiple long-term conditions (LTCs).1 Older people with cancer often require multiple medications including cancer-specific treatments, supportive care medications, and medications for pre-existing LTCs. They are therefore at higher risk of the adverse effects of polypharmacy, inappropriate prescribing, drug-drug interactions, and drug-disease interactions. Complexity of medication regimens and treatment burden can cause confusion and medicines mismanagement, thereby influencing a patient's ability to adhere to treatment with the outcome being an increased chance of treatment failure. It is thus essential that medicines be optimised in these patients.2 The Oncology Pharmacy Team based in the North West Cancer Centre, located on the Altnagelvin acute hospital site in the Western Health and Social Care Trust, Northern Ireland, secured Macmillan funding to provide a specialist medicines optimisation service to older patients about to start cancer treatment (the Medicines Optimisation in Older People with Cancer [MOOC] Service). A pharmacy technician and pharmacist were recruited and the service implemented from October 2023. The roles are new and innovative and require extensive evaluation. Aim To evaluate the introduction of the Macmillan senior pharmacy technician into the oncology pharmacy team, analysing impact on medicines optimisation and patient safety. Methods A census approach was taken to include all patients with a new cancer diagnosis and medicines reconciliation (MedRec) completed by the pharmacy technician during the study period. The technician identified and rectified any issues prior to the patient’s first scheduled treatment. Patients with significant medicines-related concerns, or aged ≥65 years and taking ≥8 drugs, were referred to the Macmillan pharmacist for holistic medication review. Data collected included number of MedRecs completed by the pharmacy technician (relative to total completed by the team weekly), cancer diagnosis, medicines-related problems identified, interventions made, other activities completed, and time directed away from the pharmacist. Analysis of patient age and number of medications taken informed whether inclusion criteria for MOOC pharmacist referral were appropriate. Results The specialist medicines optimisation service started in October 2023, however, data collection for the purpose of this study commenced on 1st January and took place over a two-month period.101 patients (aged 69.0 ± 5.7 years, range 57 -74 years)) taking an average of 12.6 medicines (range = 8-18), and recently diagnosed with cancer were reviewed by the pharmacy technician. On average, the technician completed 76.4% of medicines reconciliations each week. 120 medicines-related problems were identified, and 178 interventions made. The service yielded net cost savings of £826.34 (pharmacist time saved). Nine patients were referred to the MOOC pharmacist service; a further five patients did not consent to referral. Discussion / Conclusion Although the evaluation of the MOOC service is ongoing, this interim analysis demonstrated that integration of the pharmacy technician into the oncology team yielded cost savings and reduced and improved provision of patient-centred healthcare and safety. Inclusion criteria for the MOOC pharmacist review were confirmed via analysis of patient age and number of medicines taken.