Physicians should consider tumor size rather than anatomic features alone when managing T3a renal cell carcinoma (RCC), a new study suggests.
In a paper published in Cancer Medicine, Luping Li, MD, of Zhengzhou University in Zhengzhou, China, explained that the 8th TNM staging system identifies T3a RCC as an anatomic extrarenal invasion and does not take tumor size into account. Findings from their study of 49,586 patients with T1-3aN0M0 RCC in the Surveillance, Epidemiology, and End Results database (2004-2015) showed that T3a tumors 4 cm or less and T1b tumors did not differ in their associated all-cause and RCC-specific mortality risks.
“Consideration of tumor size as a parameter for T3a RCC may assist clinicians to select an optimum surgical approach for patients with smaller tumors that have been upstaged to T3a,” the authors wrote.
Results also showed that all-cause and RCC-specific mortality risks rose with increasing T3a tumor size: Each 1-cm increase was significantly associated with an 8% increased risk for all-cause mortality and 14% increased risk for RCC-specific mortality.
The study demonstrated that T3a tumor size stratified by a cutoff of 4 cm and 7 cm offered better prediction of RCC survival compared with only a 4 cm or a 7 cm cutoff.
Dr Li and colleagues proposed an alternative T-staging system: T1a, a combination of T1b and T3a (tumor size 4 cm or less), T2a, T2b, T3a (tumor size 4-7 cm), and T3a (tumor size greater than 7 cm). This system demonstrated greater predictive accuracy than the current 8th T-staging system, they stated.
“For better clinical practice, we should consider sub-staging the current T3a RCC stage by tumor size; this practice may improve surgical options,” they concluded.
Selected patients with small T3a RCCs may be candidates for partial nephrectomy rather than radical nephrectomy, they noted.
Li L, Shi L, Zhang J, Fan Y, Li Q. The critical impact of tumor size in predicting cancer special survival for T3aM0M0 renal cell carcinoma: A proposal of an alternative T3aN0M0 stage[WU1] . Published online December 6, 2020. Cancer Med. doi:10.1002/cam4.3629