Association of Maintenance Therapy Strategies with Survival Following First-Line Bevacizumab-Based Combination Chemotherapy in Metastatic Colorectal Cancer: A Single-Center Retrospective Observational Study

Objectives: This study evaluated the association between maintenance therapy and survival outcomes following first-line bevacizumab-based combination chemotherapy in metastatic colorectal cancer (mCRC) using real-world data. Methods: This retrospective study included 94 mCRC patients achieving disease control, defined as complete response (CR), partial response (PR), or stable disease (SD), after first-line bevacizumab-based chemotherapy (2015–2025). Patients were divided into maintenance (fluoropyrimidine ± bevacizumab, n = 44) and active surveillance (n = 50) groups. Progression-free survival (PFS) and overall survival (OS) were analyzed using a landmark approach, Kaplan–Meier methods, and Cox regression models. Results: The overall patient cohort (n = 94) had a median age of 62 years and a male predominance of 61.7%. Median OS was significantly longer with maintenance therapy than surveillance (24.8 vs. 18.0 months; p = 0.045); PFS differences were not statistically significant (11.3 vs. 6.7 months; p = 0.077). In multivariable analysis, maintenance was not independently associated with OS or PFS. Male sex, comorbidities, multiple metastases, and non-resected primary tumors independently predicted worse OS. No statistically significant treatment-by-subgroup interactions were identified in the exploratory analyses. Conclusions: These real-world data suggest a potential survival advantage associated with maintenance therapy following first-line bevacizumab-based combination chemotherapy in patients with mCRC who achieve disease control. However, this association was not maintained after multivariable adjustment, suggesting that baseline differences may have contributed to the observed findings. Trial Registration: This retrospective observational study was not prospectively registered.