Acquired cystic disease (ACD) associated renal cell carcinoma (RCC) is designated as a new subtype unique to patients with end-stage renal disease (ESRD) according to the 2016 World Health Organization (WHO) classification. However, the oncological outcomes of the prognostic factors for patients with this subtype are not fully understood. In the present study, we compared the survival of ACD associated RCC patients who underwent nephrectomy with that of patients with other histological subtypes who developed ESRD. Over 378 patients who underwent nephrectomy at three Japanese institutes between 1987 and 2016 were included in this study. A central pathologist reviewed the sections from all patients according to the 2016 WHO classification. The central pathological review showed a clear cell subtype in 165 patients (43.6%), ACD associated RCC in 112 (29.6%), papillary in 61 (16.1%), and others in 40 (10.7%). The proportion of patients with pathological stage 1 was extremely high in both clear cell and ACD associated RCC cohorts (86.6%, 85.7%). The cancer specific survival (CSS) and recurrence free survival rates of patients with ACD associated RCC were comparable with those with clear cell carcinoma and significantly better than those with the papillary subtype. The factors predictive of unfavourable outcomes were long dialysis duration, tumour size, pathological stage, grade 4 tumour, and the presence of lymphovascular invasion or a sarcomatoid component. Patients with a pre-operative dialysis duration of 20 years or longer showed a significantly worse CSS than other patients, probably owing to sarcomatoid differentiation and stage migration during the advanced stages. In conclusion, this study included the largest number of patients with ACD associated RCC, showing a survival similar to that of clear cell histology patients with ESRD, except for the rarity of late recurrence. ACD associated RCC was not as indolent as initially recognised when patients were on long term dialysis.
Copyright © 2021 Royal College of Pathologists of Australasia. Published by Elsevier B.V. All rights reserved.

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