Is mortality truly higher for oncology patients admitted to intensive care units? A matched cohort observational study

Abstract

Background Cancer patients often develop life-threatening events that prompt intensive care unit (ICU) admission. However, uncertainty regarding prognosis may hinder timely referral. We compared ICU survival in adults with solid tumors admitted emergently for medical or urgent surgical reasons with that of non-cancer controls. Methods We retrospectively analyzed 167 consecutive adults with solid tumors emergently admitted to a mixed ICU in a single center between 2010 and 2016, and compared them with two propensity-matched non-cancer cohorts. We made two 1:1 comparisons: (1) cancer and non-cancer patients matched for age, sex and do-not-intubate order; (2) the same cancer cohort matched additionally for admission diagnosis, maximum SOFA, SAPS II and Charlson Comorbidity Index. Primary outcome was ICU mortality; hospital mortality and 90-day survival were secondary endpoints. Results Cancer cases represented 4.8% of all ICU admissions; 54% had metastatic disease, 41% acute respiratory failure, and 28.7% sepsis/shock. When matched only for demographic and functional factors, cancer patients had higher intensive care unit and hospital mortality rates than controls (27.5% vs 10.8%, p < 0.001, and 35.3% vs 16.2%, p < 0.001, respectively). After matching for severity and comorbidity, ICU and hospital mortality no longer differed significantly (27.5% vs 19.8%; p = 0.094, and 35.3% vs 28.7%; p = 0.4). 90-day survival was significantly lower for cancer patients (64.7% vs 80.2%, p < 0.001), but no differences were found with controls matched for severity and comorbidity (64.7% vs 71.3%, p = 0.4). Conclusions Solid-tumor patients admitted to the ICU are generally more severely ill and thus present higher crude mortality than non-cancer patients. However, when severity and comorbidity are equivalent, outcomes are similar. Therefore, intensive care should be offered to cancer patients with reversible critical illness and acceptable baseline status, and a cancer diagnosis alone should not be considered a contraindication for ICU admission.