Abstract Rationale Major advances in precision medicine and immunotherapy have led to improved outcomes for patients with metastatic cancer, but have also introduced new, severe toxicities that can necessitate ICU admission. The overall mortality remains substantial; however, prior studies have often been single centered with small sample sizes. Therefore, we sought to provide an overview of the current literature with pooled estimates of short- and long-term mortality. Methods This study was registered a priori on Open Science Framework (10.17605/OSF.IO/438RY) and conducted per the Cochrane Handbook. A medical librarian searched MEDLINE, Embase, PubMed, Cochrane Central Register for Controlled Trials, supplemented by hand searching. Eligible studies included randomized and observational designs with 10 patients; studies were included if ≥ 70% of participants had metastatic disease when subgroup data were unavailable. The primary outcome was ICU mortality. Other outcomes included hospital, 30-day, 3-month, 6-month, and 12-month mortality. Pooled prevalence and 95% CIs were estimated using a random-effects model with Freeman-Tukey transformation. Risk of bias was assessed using the validated 10-item tool for prevalence studies. Results Of 4752 unique citations, 49 were included (N = 168,209). All studies were rated as having low risk of bias with the main threat to external validity being single-center design. Fourteen studies were multi-centered and 3 were multi-national, with the rest being single center. Across 23 studies (N = 2,918), the ICU mortality was 32% (95% CI: 25-39%; I2 = 89%; Figure 1). Across 5 studies (N = 400) with a focus on lung cancer, there was significantly higher ICU mortality (53% 43-64%; I2 = 75% versus 26% 20-34%; I2 = 86%; PQ = 0.01). Among 5 studies (N = 474) focusing on acute respiratory failure (ARF), ICU mortality was numerically higher but not statistically significant (49% 33-66%; I2 = 91% versus 26% 20-34%; I2 = 85%; PQ=0.07). Hospital mortality was 50% (44-56%; I2 = 99%; N = 157,682), 30-day mortality was 48% (39-57%; I2 = 84%; N = 1,067), 3-month mortality was 69% (62-74%; I2 = 80%; N = 1,296), 6-month mortality was 70% (59-79%; I2 = 91%; N = 1,310), and 12-month mortality was 84% (71-91%; I2 = 95%; N = 1,446; Figure 1). Conclusions Among critically ill adults with metastatic cancer, about one-third died in the ICU, half survived to hospital discharge, and 12-month mortality was 84%. There was considerable heterogeneity in mortality estimates, with worse outcomes in lung cancer. Given that ICU admission criteria and illness severity may differ, large multi-center studies are needed to clarify temporal trends and identify management strategies to improve outcomes. This abstract is funded by: None
Heybati et al. (2026) studied this question.