Imaging Increases RCC Diagnoses

Renal cell carcinoma (RCC) is the most common histologic type of urologic cancer. Worldwide, the age-standardized rate of RCC is 4.4/100,000; higher income countries have higher rates of RCC. Up to one-third of patients with RCC have metastatic disease at presentation, although recent studies have demonstrated smaller proportions. It is possible that the widespread use of imaging performed for a variety of reasons is associated with the increase of incidentally diagnosed RCC.

Ido Orlin, MD, and colleagues at the Lady Davis Medical Center, Haifa, Israel, conducted a retrospective analysis of trends in cancers of the kidney and renal pelvis in Israel. Results were reported in conjunction with the ASCO 2019 Annual Meeting.

The analysis included all cases of RCC of the kidney and renal pelvis neoplasms that were reported to the Israel National Cancer Registry for the years 2000 through 2015. The researchers extracted demographic and clinical variables from the registry, including sex, population group, dates of birth/death, tumor size, stage at presentation according to the Surveillance, Epidemiology and End Results (SEER) summary staging manual 2000. The overall and population group age-standardized incidence of RCC were calculated using the direct method and the Segi World Standard population.

The researchers identified a total of 9595 cases of RCC. The average age-standardized rate was 7.7/100,000. The incidence of RCC was highest in the seventh decade of life with a male/female ratio of 1.7:1. The incidence was higher in the Jewish population than in the Arab population,

Ten percent of cases had metastatic disease at the time of diagnosis; the percentage was unchanged during the study period. Nearly two thirds of localized tumors were masses smaller than 4 cm, a trend that saw a significant increase during the study period (P<.001). Five-year overall survival for localized disease was 86%; for metastatic disease, 5-year overall survival was 12%. Survival rates were similar in the Jewish and Arab populations (P=.06).

In conclusion, the researchers said, “RCC incidence and survival in Israel mirror those of other western countries. The proportion of cases with distant spread at diagnosis is smaller than elsewhere reported. Small incidental renal masses (less than 4 cm) are increasingly diagnosed in the localized stages, possible due to increased using of imaging.”

Source: Orlin I, Silverman B G, Dekel Y, Stein A, Friedman B, Ben-Lasson M. Renal cell carcinoma epidemiology in the era of widespread imaging. Abstract of a poster published in conjunction with the American Society of Clinical Oncology 2019 Annual Meeting, May 31-June 4, 2019, Chicago, Illinois.