Baseline serum albumin level as a predictive factor for the efficacy of trifluridine/tipiracil plus bevacizumab in metastatic colorectal cancer: a retrospective cohort study

Trifluridine/tipiracil (FTD/TPI) combined with bevacizumab (BEV) has become a standard later-line therapy for metastatic colorectal cancer (mCRC). However, predictive biomarkers of treatment efficacy remain limited. Serum albumin (Alb)—reflecting nutritional and inflammatory status—has been reported as a prognostic factor in various malignancies, but its predictive value in patients receiving FTD/TPI plus BEV is unclear. We examined whether baseline Alb levels are linked to treatment outcomes in patients with metastatic CRC receiving FTD/TPI plus BEV, aiming to clarify if Alb could serve as a predictive marker of therapeutic efficacy. We retrospectively analyzed patients with unresectable or recurrent mCRC treated with FTD/TPI plus BEV at Fukuyama Medical Center between December 2017 and March 2024. Patients were divided into High- or Low-Alb groups based on an optimal cutoff derived from receiver operating characteristic (ROC) analysis for progression-free survival (PFS). The primary endpoint was PFS, and the secondary endpoint was overall survival (OS). Survival outcomes were assessed using the Kaplan–Meier method and Cox proportional hazards models. Sixty-nine patients were included (median age, 69 years). ROC analysis identified an Alb cutoff of 3.7 g/dL (area under the curve: 0.740). Using this cutoff, 39 patients (56.5%) were included in the High-Alb group. Patients in the High-Alb group had significantly lower lactate dehydrogenase (LDH) and C-reactive protein levels than those in the Low-Alb group. The median PFS (5.2 vs. 3.0 months; p < 0.01) and OS (15.6 vs. 6.0 months; p < 0.01) were significantly longer in the High-Alb group than in the Low-Alb group. In the multivariate analysis, Alb ≥3.7 g/dL was independently associated with improved PFS (hazard ratio [HR]: 0.40, 95% confidence interval [CI]: 0.22–0.73, p = 0.003), whereas LDH ≥338 U/L was associated with shorter PFS (HR: 2.31, 95% CI: 1.28–4.32, p = 0.009). Baseline serum Alb levels were associated with survival outcomes in patients with mCRC treated with FTD/TPI plus BEV. Thus, Alb may represent a simple and clinically accessible marker with potential predictive value. Initiating FTD/TPI plus BEV before a substantial decline in nutritional or inflammatory status may help achieve more favorable outcomes.