Changes in the Characteristics of Kidney Cancer Detection During the COVID-19 Pandemic.

: The COVID-19 pandemic affected cancer care globally. Our objective was to analyze the demographic and clinical characteristics of kidney cancer (KC) patients between the pre-COVID-19 and COVID-19 periods. We also aimed to assess how KC was discovered-incidentally or symptomatically-and identify factors predicting the mode of discovery and advanced-stage disease. : This retrospective study analyzed data from 400 patients aged 18 years or older diagnosed with kidney cancer (KC) at a large regional Hungarian clinical center during two time periods: the pre-COVID-19 period (1 January 2019 to 15 March 2020) and the COVID-19 period (16 March 2020 to 13 May 2021). Demographic and clinical information, including the mode of cancer discovery, was collected for all patients. : During the pandemic, monthly kidney cancer diagnoses declined by 10.3%. The proportion of female patients rose significantly from 31.9% to 42.9% ( = 0.023). Incidental tumor detection decreased from 82.4% to 72.4% ( = 0.018), while symptomatic presentation increased from 14.2% to 19.4%, although not significantly ( = 0.166). Non-incidental detection was associated with a 3.42-fold increase in odds of advanced cancer pre-pandemic and a 2.03-fold increase during the pandemic. Symptomatic presentation raised these odds by 4.51 and 2.76 times, respectively. : Our study revealed changes in kidney cancer detection during the pandemic, including a rise in the proportion of female patients and a decline in case numbers, likely due to reduced incidental findings. Non-incidental discovery and symptom presence remained predictors of advanced-stage disease, although the odds were lower. Various factors-such as changes in healthcare access and gender-related differences in health-seeking behavior-may possibly explain these changes. Our findings support the critical role of incidental detection in high-risk populations.