AUA 2006 - ABST [711] ARE SMALL RENAL TUMORS HARMLESS? ANALYSIS OF HISTOPATHOLOGICAL FEATURES ACCORDING TO TUMOR SIZE IN TUMORS 4 CM. OR LESS IN DIAMETER

Mesut Remzi*, Mehmet Oezsoy, Hans-Christoph C Klingler, Martin Susani, Matthias Waldert, Christian Seitz, Joerg Schmidbauer, Enis Tanovic, Michael Marberger, Vienna, Austria.

Introduction and Objective: Small renal tumors detected incidentally are considered to have less aggressive potential. This assumption is mainly based on their low tendency to increase in size at serial imaging studies, but histopathological data on larger patient series are scant.

Methods: 287 tumor bearing kidneys in which solid tumors less than or equal to 4cm in diameter were detected by cross-sectional imaging and subsequently removed surgically were reviewed. Tumor size as documented by preoperative CT scan was correlated to the histological diagnosis, and in case of malignancy to tumor type, pathological TNM stage and nuclear (Fuhrman) grade. With multifocal lesions the largest single tumor was considered as reference lesion, but multifocality was also considered as a separate parameter.

Results: At a mean tumor diameter of 2.94±0.87cm overall 65 (22.6%) of tumors were less than or equal to 2cm, 103 (35.9%) 2.1-3.0cm, and 119 (41.5%) 3.1-4cm in diameter. 56 (19.5%) tumors were found to be benign, with no correlation to tumor size (p=0.660, Pearson test). 227 (79.1%) were renal cell cancer (RCC) with 159 (70.0%) clear cell RCC, 47 (20.7%) papillary, 11 (4.8%) chromophob, and 10 others, with no correlation to tumor diameter. 31 (13.6%) of kidneys had multifocal RCC, with a significant correlation to larger tumor diameter (p=0.048) and papillary RCC subtype (p=0.018). 2 (4.2%), 4 (5%) and 25 (25.5%) of RCC in less than or equal to 2cm, 2.1-3cm, and 3.1-4cm had Fuhrman grade G3/4, respectively (p=0.0007). Advanced stage (greater than or equal to pT3a) was documented in 2 (4.2%), 12 (14.9%), and 35 (35.7%) for the same categories, respectively (p=0.0023). Whereas distant metastases were diagnosed in only 4 RCC patients with tumors less than or equal to 3cm this was in 10 (8.4%) of patients with RCC from 3.1-4cm (p=0.045).

Conclusions: The aggressive potential of small RCC increases dramatically beyond a tumor diameter of 3cm. Given the difficulty in measuring tumor diameters reliably by sequential imaging studies, the threshold for selecting patients for a surveillance strategy should be selected well under this parameter.

Discussed Poster: Kidney & Ureteral Cancer: Evaluation & Treatment (I) (1:00 PM-4:00 PM)

Please log-in or register in order to submit comments.

Powered by AkoComment!