Background and importance Trifluridine/tipiracil (TAS-102) is a drug with a doubtful clinical benefit according to the ESMO-MCBS scale (values=1–2) in the treatment of patients with metastatic colorectal cancer (mCRC) who have previously been treated with, or are not considered candidates for, available therapies, including fluoropyrimidine, oxaliplatin and irinotecan based chemotherapies, anti-VEGF agents and anti-EGFR agents.

Aim and objectives The objective of this study was to evaluate the effectiveness and safety of TAS-102 in mCRC in real world use.

Material and methods An observational, retrospective, descriptive study was conducted in all patients with a diagnosis of mCRC who received treatment with TAS-102 from January 2017 to April 2019. Demographic (sex and age) and clinical variables (RAS gene mutation, primary tumour location, duration of treatment, progression free survival (PFS) and adverse events) were analysed. Progression was analysed according to the response evaluation criteria in solid tumours (RECIST V.1.1).

Results 32 patients with mCRC were included. Mean age was 69.4 years (IQR 61.7–75.4). RAS wild-type was detected in 53.1% of patients. The primary location was the colon in 71.9% (43.5% unspecified, 30.5% left, 26% right), the rectum in 25% and both in 3.1%. 3.1% of patients received two previous lines of treatment, 68.8% three and 28.1% four (schemes with capecitabine±oxaliplatin, FOLFOX, FOLFIRI and regorafenib). The addition of anti-VEGFR/EGFR therapy was not considered a differentiated scheme.

All patients progressed to fluoropyrimidines, 96.9% progressed to irinotecan and 53.1% to cetuximab. 100% of patients received biological therapy. Bevacizumab was administered to 90.6% of patients, aflibercept to 59.4% and cetuximab/panitumumab to 53.1%. Mean duration of treatment (months) was 2.3 (IQR1.6–3.3). At the time of data collection, 81.2% had progressed, 12.5% stopped because of toxicity and 6.2% remained on the regimens. Median PFS was 2.3 (95% CI 1.5 to 3.0) months. Any grade adverse events occurred in 90.6% of patients. These were asthenia (65.6%), pain (56.2%), neutropenia (40.6%; differentiated as 38.5% grade 3, 46.1% grade 2, 15.4% grade 1), diarrhoea (34.4%), nausea (31.3%), anorexia (18.7%), liver toxicity (18.7%), infections (15.6%) and haemorrhages (9.4%).

Conclusion and relevance In our study, patients treated with trifluridine/tipiracil presented toxicity and a PFS similar to that observed in the pivotal clinical trial (2.0 (1.9 to 2.1)). TAS-102 is a low clinical benefit option in mCRC.

Conflict of interest No conflict of interest