Mortality in acute ischemic stroke patients with new cancer diagnosed during the index hospitalization versus after discharge

Background: Early diagnosis of previously unknown cancer (i.e., occult cancer) after an acute ischemic stroke (AIS) could result in faster initiation of cancer therapy and potentially improve clinical outcomes. Our study aimed to compare mortality rates between AIS patients with occult cancer diagnosed during the index stroke hospitalization versus those diagnosed after hospital discharge. Methods: Among consecutive AIS patients treated at our stroke center from 2015 through 2020, we identified new cancer diagnoses made within the year after the AIS. We used multivariable Cox regression analyses to evaluate the association between the timing of occult cancer diagnosis (during the AIS hospitalization versus after discharge) and long-term survival. Results: Of 3894 AIS patients with available long-term follow-up data, 59 (1.5 %) were diagnosed with a new cancer within one year after index stroke. Of these, 27 (46 %) were diagnosed during the index hospitalization and 32 (54 %) were diagnosed after discharge. During a median follow-up of 406 days (interquartile range, 89–1073), 70 % (n = 19) of patients whose cancer was diagnosed during hospitalization had died, compared to 63 % (n = 20) of patients whose cancer was diagnosed after discharge (p = 0.58). In our main multivariable model, there was no difference in long-term mortality between patient groups (adjusted hazard ratio, 1.16; 95 % confidence interval, 0.53–2.52; p = 0.71). Conclusions: In this analysis, timing of a new cancer diagnosis after AIS did not seem to influence patients’ long-term survival. Given the fairly small number of included patients with previously occult cancer, larger multicenter studies are needed to confirm our results.