Background: Takotsubo syndrome (TTS), primarily an acute myocardial inflammatory condition engendered by catecholamine exposure, is associated with similar long-term mortality rates to those of patients with acute myocardial infarction. However, there is increasing evidence of a nexus between TTS and underlying malignancies:many patients have antecedent cancer (A/Ca), while incremental risk of late cancer-related death has also been reported. Purpose: To evaluate potential interactions between A/Ca among TTS patients and both early and late clinical course.Methods: Three hundred forty-six consecutive TTS patients [aged 69 ± 13 (SD) years, males: 8.2%] were prospectively followed up for a median duration of 4.1 (IQR 2.2-6.4) years. Associations between A/Ca and severity of acute attacks, in-hospital complications and long-term death rates were sought utilising univariate analyses followed by multiple logistic regression analysis. Results: A/Ca (present in 16.8% of patients) was associated with (i) greater elevation of hs-CRP and NT-proBNP concentrations (p = 0.01 and 0.04, respectively), (ii) more complicated in-hospital clinical course, with major adverse cardiac events (MACE) in 30.9% of patients, compared to 18.2% in non-A/Ca patients (p = 0.04). Long-term all-cause mortality rate was also greater [hazard ratio (HR) = 2.4, p = 0.0001] in A/Ca patients, with an excess cardiovascular (CVS) fatality rate (HR = 3.1, p = 0.001). On multivariate analysis, male gender, peak plasma concentrations of normetanephrine and hs-CRP, early arrhythmias and development of shock, but not A/Ca per se, were all independently associated with increased long-term mortality rate. Furthermore, patients discharged on β-adrenoceptor antagonists (βBl) or angiotensin converting enzyme inhibitors/ angiotensin receptor blockers (ACEi/ARB) had lower long-term mortality rates (β = − 0.2, p = 0.01; β = − 0.14, p = 0.05, respectively). Conclusions: (1) A/Ca is associated with greater clinical severity of initial TTS attacks and substantially greater longterm CVS-related as well as all-cause mortality.(2) Post-discharge therapy with either βBl or ACEi/ARB is associated with reductions in long-term mortality rates. Overall, the current data suggest operation of substantial interactions between neoplasia and TTS, both at the level of pathogenesis and of outcomes.