Immune Checkpoint Inhibitors and Other Immunotherapies in the Treatment of Spinal Column Tumors: A Systematic Review and Meta-analysis of Efficacy, and Safety

Introduction: Spinal metastases affect up to 40% of systemic cancer patients, with overall survival averaging less than six months. Traditional chemotherapeutic agents have unsatisfactory results, leading to immunotherapy (IT) investigations. There is no clear consensus on the benefits and risks of IT for spinal tumors. This study assesses the current literature to determine IT safety and survival efficacy.

Methods: Following PRISMA guidelines, a systematic search was conducted across Embase, Scopus, Web of Science, and PubMed through September 15th, 2024. Patient demographics, disease control, survival, and toxicity were analyzed using R

Results: A total of 416 articles were screened, with 17 included for qualitative analysis and four for quantitative analysis. This review encompasses 166 patients (48.2% female) with a median age of 50.13 years. Prior to IT, 44 patients had undergone surgery and 110 had received radiotherapy. Primary tumors originated from non-small cell lung cancer in 86 patients (51.8%), breast cancer in 41 (24.7%), renal cell carcinoma in 35 (21.1%), and other cancers in 4 (2.4%). The most common IT was anti-PD1 (90.1%), followed by anti-CTLA4 therapy. Among 86 patients with survival data, 65 patients passed away within 100 months (median survival = 12.3 months; 95% CI = 8.2–18.8). Of the 110 patients analyzed for toxicity, the overall proportion of affected individuals differed (8/37 [22%] vs. 6/73 [8%]), though there was overlap in 95% confidence intervals (0.10–0.38 vs. 0.03–0.17). The proportional risk of toxicity was 0.13 (95% CI = 0.08–0.20), with significant heterogeneity between the two cohorts (I² = 73%, τ² = 0.1509, p = 0.05).

Conclusion : IT showed comparable survival to surgery, a promising result for conservative treatment. Toxicity also demonstrated a lower risk ratio in comparison with radiotherapies. The limited number of studies and combined use of radiosurgery with immunotherapy may explain the significant heterogeneity in toxicity analysis and minor improvement in survival. Further investigations of IT for spinal metastases are needed to understand its place in treatment algorithms.