Poorer survival after out-of-hospital cardiac arrest among cancer patients: a population-based register study

Aims: The association between cancer and survival after out-of-hospital cardiac arrest (OHCA) has not been thoroughly investigated. We aimed to address this knowledge gap using national, population-based registries. Methods and results: For this study, 30 163 patients with OHCA (≥18 years) were included from the Swedish Register of Cardiopulmonary Resuscitation. Through linkage to the National Patient Registry, 2894 patients (10%) with cancer diagnosed within 5 years prior to OHCA were identified. Differences in 30-day survival between patients with cancer and controls (defined as patients with OHCA without previous cancer diagnosis) were assessed related to cancer stage (locoregional vs. metastasized cancer) and cancer site (e.g. lung cancer, breast cancer, etc.) using logistic regression adjusted for prognostic factors. Long-term survival was presented as a Kaplan-Meier curve. For locoregional cancer, no statistically significant difference in return of spontaneous circulation (ROSC) was seen compared with controls, and metastasized disease was associated with a poorer chance of ROSC. Cancer was associated with a lower 30-day survival for all cancers [adjusted odds ratio (OR) 0.57, confidence interval (CI) 0.49-0.66], locoregional cancer (adjusted OR 0.68, CI 0.57-0.82), and metastasized cancer (adjusted OR 0.24, CI 0.14-0.40) compared with controls. A lower 30-day survival compared with controls was seen for lung, gynaecological and haematological cancers. Conclusion: Cancer is associated with poorer 30-day survival after OHCA. This study suggests that cancer site and disease stage are more relevant factors than cancer in general with regard to its effect on survival after OHCA.