In this issue of the International Journal of Urology, Kobayashi et al. examined the clinicopathological features, risk factors and prognosis in renal cell carcinoma (RCC) patients with late recurrence.1 As they described, one of the unique characteristics of RCC might be a biological potential for recurrence or metastasis over 5 years after primary surgical treatment with curative intent. 2,3 In the present study, 8.3% of the patients who underwent primary radical surgery and remained free of recurrence after 5 years had late recurrence of disease, which was consistent with the results in previous reports.In terms of risk factors of late recurrence, a risk model (PRELANE score), including factors of lymphovascular invasion, Furman grade and tumor stage, had been recently developed and validated on the basis of a large multicenter database of the Western population.3 The present study showed that vascular invasion (including microscopic and gross invasion) at the primary site was the only predictor of late recurrence, and the authors reported that larger primary tumor size and more aggressive tumor pathology might be risk factors of early rather than late recurrence.1 In contrast, a previous study in the Japanese population reported that lymph node metastasis was the only factor to predict late recurrence. 4 Further large Japanese cohort studies will be expected to determine risk factors of late recurrence in Japanese RCC patients and to compare the findings with those in Western patients.From the results regarding risk factors of late recurrence in the present study, the hypothesis that a lower malignant potential of cancer cells results in late recurrence might arise. As expected, Kaplan-Meier curves showed better overall and disease-specific survivals in patients with late than in those with early recurrence, and this finding was consistent with that of a previous study.5 However, four (9.8%) patients with late recurrence had rapid disease progression and died within 1 year after recurrence. Alterations in the character of cancer before the recurrence clinically emerged were suggested, and the pathological and molecular mechanisms of these alterations should be elucidated in further examinations as the next challenging issue.