Renal mass size predicts the likelihood of harboring synchronous lung metastasis, a finding that could help physicians decide whether chest imaging is warranted, according to study data presented at the 36th annual European Association of Urology congress.
The study, which included 253,838 patients with a renal mass who underwent staging chest imaging from 2011-2016, showed that the likelihood of synchronous lung metastases increases proportional to renal mass size, but these metastases occur in less than 1% of patients with renal masses less than 4 cm in diameter.
“Our findings provide physicians with the necessary information to assess a patient’s risk of synchronous lung metastasis based upon the initial renal mass size,” said investigator Marcus Jamil, MD, of the Vattikuti Urology Institute at Henry Ford Hospital in Detroit, Michigan, who presented study findings.
A 4 cm cutoff would result in a nearly 50% reduction in unnecessary imaging in all patients presenting with a renal tumor, Dr Jamil said.
The investigators identified the study population using the National Cancer Database. Of the
253,838 patients, 120,386 (47%) had a renal mass less than 4 cm and 14,524 (5.7%) had synchronous lung metastases at diagnosis. The median tumor size for patients with and without synchronous lung metastasis was 9 cm and 4 cm, respectively. Of the 120,386 patients with a small renal mass, 1135 (0.9%) had synchronous lung metastases. These 1135 patients made up 8% of the 14,524 patients with synchronous lung metastases.
Thus, in patients with a tumor size less than 4 cm, a 4 cm cut off for performing chest imaging would risk missing 0.9% of synchronous lung metastases, according to Dr Jamil.
The 4 cm threshold could be useful in counseling patients about the benefits and risks of undergoing staging chest imaging and possibly reduce exposing patients to unnecessary radiation and decrease health care costs, he said.
Jamil M, Hanna R, Sood A, et al. Renal mass size and presence of synchronous lung metastasis at time of diagnosis: Implications for chest imaging. Presented at: EAU 2021, held July 8-12. Abstract P0640.