Correspondence: Cancer incidence and mortality after a first-ever venous thrombosis in northern Sweden.

We congratulate Hägg et al. on their study investigating cancer incidence and mortality following first-ever venous thromboembolism (VTE), which provides valuable insights into VTE as a potential marker for underlying malignancies. However, we highlight concerns regarding healthy user bias, the unclear follow-up duration, and inconsistent adjustment in the statistical analysis. We also suggest the use of the Fine-Gray subdistribution hazard model to address competing risks, and the accurate reporting of sex-gender terminology. Lastly, we advise caution in concluding a high incidence of cancer following first-ever VTE without pre-VTE data for comparison and recommend acknowledging potential surveillance bias when interpreting the higher cancer detection rate within 6 months of VTE diagnosis.