Renal cell carcinoma incidence rates and trends in young adults aged 20-39 years.

Background: The burden of renal cell carcinoma (RCC) in young adults received marginal attention. We assessed contemporary gender, race and stage-specific incidence and trends of RCC among young adults (20-39 years-old) in the United States.

Methods: Within Surveillance, Epidemiology, and End Results database (2000-2016), patients aged 20-39 years with histologically confirmed RCC were included. Age-standardized incidence rates (ASR per 100,000 person-years) were estimated. Temporal trends were calculated through joinpoint regression analyses to describe the average annual percent change (AAPC).

Results: From 2000-2016, 7767 new RCC cases were recorded (ASR 0.6, AAPC  + 5.0 %, p < 0.001). ASRs were higher in males than in females (0.7 and 0.5, respectively) and increased significantly in both genders (AAPC + 5.0 % and +4.7 % both p < 0.001, respectively). Non-Hispanic American Indian/Alaska Native had the highest incidence (ASR 1.0) vs. non-Hispanic Asian or Pacific Islander the lowest (ASR 0.3). ASRs significantly increased in all ethnic groups. T1aN0M0 and T1bN0M0 stages showed the highest incidence and increase (ASR 0.3, AAPC + 5.9 %, p < 0.001 and ASR 0.1, AAPC + 5.7 %, p < 0.001, respectively). Also regional and distant stages increased (AAPC + 3.7 %, p = 0.001 and AAPC + 1.5 %, p = 0.06). The most frequent tumor characteristics were G2 (44.4 %, ASR 0.3, AAPC + 6.3 %, p < 0.001) and G1 (13.1 %, ASR 0.1, AAPC + 1.1 %, p = 0.2), as well as clear cell histology (54.8 %, ASR 0.3, AAPC  + 7.6 %, p < 0.001).

Conclusions: RCC in young adults is rare, but increasing. This is mainly due to T1aN0M0 tumors. Nonetheless, also regional diseases are significantly increasing. Differences between ethnic groups exist and may warrant further research.