Total En Bloc Spondylectomy in Modern Spine Oncology: Selection-Relevant Survival Signals and Treatment Burden in a Single-Center Cohort

Background/Objectives: Total en bloc spondylectomy (TES) remains one of the most invasive and selectively used procedures in spine oncology. Its role has become more selective in the modern era of stereotactic body radiotherapy, separation surgery, targeted systemic therapy, immunotherapy, and multidisciplinary cancer care. This study evaluated long-term survival, imaging-defined systemic disease burden, operative morbidity, patient-reported outcomes, and frailty-related variables after TES in a rare single-center cohort, with the goal of identifying selection-relevant survival and treatment-burden signals rather than developing a validated decision algorithm. Methods: We performed a retrospective single-center cohort study of consecutive adults who underwent TES for spinal tumors between 2011 and 2022. Of the 36 screened patients, 30 had sufficient clinical and survival data for analysis; patients without reliable survival or last-contact data were not included. Contrast-enhanced CT and PET-CT were reviewed for extraspinal metastases, lymphadenopathy, pleural effusion, and soft-tissue extension. Survival was analyzed using Kaplan–Meier methods, log-rank testing, and exploratory univariate Cox regression. Patient-reported outcomes included the Oswestry Disability Index (ODI) and SF-36 when available; frailty was summarized with the modified frailty index-5 (mFI-5) when component data were present. Results: The cohort included 13 men and 17 women with a mean age of 54.8 ± 15.2 years. At final follow-up, 18 patients had died, and 12 were alive. Five-year overall survival was approximately 76% in the full cohort. Extraspinal metastases were present in 72.2% of deceased patients compared with 8.3% of survivors and showed the clearest exploratory association with increased mortality (HR 3.46, 95% CI 1.23–9.78; p = 0.019). Metastatic disease demonstrated inferior survival compared with primary bone or soft-tissue tumors. Perioperative blood loss and transfusion burden were substantial but were not associated with survival in univariate analysis. ODI and SF-36 data were available only in small subsets and were therefore interpreted as descriptive signals of treatment burden. Conclusions: TES remains relevant in modern spine oncology, but only as an increasingly selective intervention. In this rare cohort, systemic disease burden, particularly extraspinal metastases, was the clearest selection-relevant survival signal, while blood loss, transfusion requirements, complications, and limited patient-reported outcomes illustrated substantial treatment burden. These findings do not establish a validated selection algorithm but support a contemporary decision threshold that integrates tumor biology, systemic disease status, anticipated margins, physiologic reserve, operative morbidity, and patient goals.