Aims & objectives: This study evaluates the feasibility and clinical outcomes of using 3D-printed polyetheretherketone (PEEK) patient-specific implants (PSI) for vertebral body replacement (VBR) in patients with spinal tumors. The research question focuses on postoperative results, implant integration, and complications over a 12-month period. Methods: A single-center, retrospective case series analyzed five patients who underwent spinal reconstruction after tumor resection using PEEK 3D VBR between April 2022 and June 2023. Inclusion criteria were thoracic/lumbar spinal tumors, tumor resection with PEEK 3D VBR reconstruction, and follow-up exceeding 12 months. PEEK implants were created using fused filament fabrication from medical-grade PEEK. Patient data included demographics, medical history, tumor characteristics, and surgical outcomes. Radiological evaluations assessed bony fusion, local angle changes, and segment height stability. Descriptive statistical analyses were performed using R software. Results: The mean follow-up duration was 19.2 months. All patients remained alive, with one experiencing local recurrence. Postoperative imaging showed a decrease in local angle with no significant changes during follow-up. Segment heights remained stable, and no PEEK 3D VBR subsidence or hardware failure was observed. Bony fusion was observed in all patients. Conclusions: The use of PEEK 3D printed PSI for VBR in spinal tumor patients demonstrates promising feasibility and clinical outcomes, with stable implant integration and minimal complications over a 12-month period. Further studies with larger cohorts are recommended to validate these findings. © 2024 Professor P K Surendran Memorial Education Foundation