Higher AJCC stage at primary tumor diagnosis may predict shorter survival in metastatic uveal melanoma.

In this international collaboration, we examined whether survival in metastatic uveal melanoma is associated with primary tumor size at initial diagnosis. A total of 128 and 205 patients with American Joint Committee on Cancer (AJCC) stage IV disease were included from the Netherlands and Sweden, respectively. Across both cohorts, patients whose tumors had a largest basal diameter ≥ 16 mm or a higher AJCC stage presented with a greater number of hepatic metastases and showed shorter Kaplan-Meier overall survival from the time of metastatic detection. However, this association did not persist after adjustment for the number of hepatic metastases in multivariate Cox regression and a Markov multi-state model. These findings suggest that primary tumor size is associated with survival in metastatic disease and the burden of metastatic lesions at detection, indicating a potential survival benefit of primary tumor treatment. Nevertheless, caution is warranted when interpreting these results, as they differ from some previous reports.