72 Effectiveness and safety of Lonsurf as a third-line palliative agent in metastatic colorectal cancer: is it a worthwhile therapy for our patients?

<h3>Background</h3> Trifluridine/Tipiracil (LONSURF) is approved in the UK for the treatment of refractory metastatic colorectal cancer, following modest improvements in overall survival in the RECOURSE trial compared to best supportive care and placebo. This study aimed to evaluate the safety and efficacy of LONSURF in a local population at Queen Alexandra Hospital (QAH), Portsmouth, and to compare outcomes with phase 3 clinical trials, guiding prognostication and treatment decisions for our patients. <h3>Methods</h3> A retrospective analysis was conducted using the local chemotherapy database at QAH, identifying patients who started on LONSURF (n=56), with an age range of 23–83 years. Data included the number of treatment cycles received, maximum tolerated dose, progression of cancer markers, radiological response, adverse effects, and reasons for treatment discontinuation. Survival benefit was assessed by recording the duration from the first treatment cycle to the date of death. <h3>Results</h3> Only 9% of patients demonstrated radiological stability, while over 90% showed disease progression on imaging. The proportion of patients with stable disease or a positive response to treatment was lower than reported in clinical trials. Adverse events associated with LONSURF were consistent with those observed in trials, though the differentiation between treatment-related side effects and those from underlying disease remains challenging. <h3>Conclusion</h3> Our analysis indicates a limited impact of LONSURF on disease progression in this patient cohort, raising questions about the value of initiating treatment given the potential for side effects and grade 3 adverse events. Despite the alignment of adverse event rates with clinical trial data, the modest efficacy observed suggests that a more selective approach may be needed when considering LONSURF for patients with refractory metastatic colorectal cancer.