Metachronous renal cell carcinoma: an unbeatable leviathan?

Renal cell carcinoma (RCC) is a heterogeneous tumor, even within the same histological type (1). This feature, combined with non-modifiable (age, sex, race, genetic), and modifiable (family, and smoking history, hypertension, drugs) predisposing factors, increases the risk to develop metachronous RCC at long-term (2). Besides, concerns still remain about what a metachronous tumor is, and on what features allow to recognize it as metachronous rather than recurrence (3,4). Understanding the predisposing factors, and find a univocal portrayal of “metachronous” might shift the history of this condition. Nevertheless, literature have not found an answer to these questions yet, and evidence remains sparse. Because of this, we strongly applaud the authors for their effort to provide a further insight on this controversial topic fueling the debate, and giving hint for future studies.