Thromboembolism in patients with melanoma receiving immune checkpoint inhibitors: incidence and risk factors

Background

Immune checkpoint inhibitors (ICIs) may increase the incidence of thromboembolisms (TEs). In patients with melanoma, the risk of TE and its association with the disease setting remains largely unknown. This study investigated the incidences of arterial thromboembolism (ATE) and venous thromboembolism (VTE) and associated risk factors in ICI-treated patients with melanoma in the advanced and adjuvant disease settings.

Patients and methods

ATE and VTE incidences were retrospectively collected from patients receiving ICI in the advanced (irresectable stage III/IV) or adjuvant (stage III/IV, after complete resection) disease setting until 2 years or after censoring. Associations between characteristics and ATE/VTE were analyzed using the Fine–Gray model, with all-cause death as competing risk.

Results

In the advanced disease cohort, 7 (2.2%) and 16 (5.1%) of 315 included patients developed ATE and VTE, respectively. In the adjuvant cohort, 3 (2.1%) and 2 (1.4%) of 143 included patients developed ATE and VTE, respectively. In the advanced cohort, ICI combination therapy was associated with VTE [standardized hazard ration (sHR) 4.42, 95% confidence interval (CI) 1.58-12.38, P = 0.005] and higher body mass index (BMI) with ATE (sHR 1.09 per point BMI increase, 95% CI 1.02-1.17, P = 0.017), with a trend toward VTE (sHR 1.06, 95% CI 1.00-1.13, P = 0.055). In the adjuvant cohort, VTE history was associated with increased combined TE (sHR 11.22, 95% CI 1.83-68.68, P = 0.009) and higher BMI with a trend toward increased TE (sHR 1.19, 95% CI 0.97-1.46, P = 0.091).

Conclusions

Both ATE and VTE incidences seem to be modest in patients with melanoma receiving ICI in both disease settings. Patients with higher BMI and who are prescribed ICI combination therapy might be at increased thrombotic risk.