In the RECOURSE trial which lead to its accreditation, Lonsurf 
(trifluridine/tipiracil) was shown to extend progression free survival (PFS) by 
1.8 months in metastatic colorectal cancer. This Trust audit aims to assess the 
average quantity of cycles of Lonsurf received by participants and the length of 
time it extends PFS. Similarly, to identify how many participants required a 
dose-reduction or experienced toxicities which necessitated supportive 
therapies. Quantitative data was collected retrospectively from all participants 
who had received ≥1 cycle of Lonsurf from The Clatterbridge Cancer Centre (CCC) 
from 2016 until June 2020. Participant electronic patient records were accessed 
to identify toxicity grading, length of treatment received, the date progression 
was identified, if dose reductions were applied and if supportive therapies were 
administered. Lonsurf extends PFS in patients with metastatic colorectal cancer 
at CCC by 3.0 months (95% CI: 2.73-3.27) and average treatment length was 
2.4 months. However, 78 participants (41.5%) received a dose reduction due to 
toxicities. A total of 955 toxicities were recorded by participants; the most 
commonly reported toxicities irrespective of grade were fatigue (33.8%), 
diarrhoea (13.8%) and nausea (12.3%). The most common grade ≥3 toxicities were 
constipation and infection. The most frequently utilised supportive therapies 
were loperamide (49.6%) and domperidone (49.1%). Granulocyte colony stimulating 
factor (GCSF) was required by patients on 5 occasions (0.3%) in total. Lonsurf 
extends median PFS in patients with metastatic colorectal cancer by 3.0 months. 
The most common grade ≥3 toxicities which necessitated supportive therapies or a 
dose reduction were gastrointestinal and infection.