Purpose: To assess nationwide the pathologic characteristics and trends in type of surgery and pathologic reporting in surgically managed renal tumors ≤ 4 cm.
Materials and methods: A review of all pathologic reports of primary small renal masses operated on in the Netherlands during the period 1995 to 2005 was performed. The data source was a nationwide central archive of histocytopathology (Patologisch Anatomisch Landelijk Geautomatiseerde Archief). Tumors were stratified into three groups: ≤ 2, 2.1 to 3.0, and 3.1 to 4.0 cm. Age, sex, type of operation, and tumor pathology were analyzed. For renal-cell carcinomas, grade (3-tiers Fuhrman) and stage (2002 Tumor, Node, Metastasis) were assessed. Trends in type of surgery (radical or partial nephrectomy [PN]) and pathologic reporting during the study period were analyzed.
Results: Of all operated primary kidney tumors, 25.3% were ≤ 4.0 cm. The mean age of the patients was 63.1 years (standard deviation 11.7), and the male/female ratio was 3:2. Only 7.5% were benign tumors, and 9.8% were locally advanced (≥ T₃). Tumors ≤ 3.0 cm were more likely to be benign (P = 0.006) and of lower stage (P ≤ 0.001) than tumors of 3.1 to 4 cm. PN was performed in 16.5% of the cases. Grade and subtype were reported in 55% of the cases. The rate of PNs performed increased during the decade. There was a trend in increased reporting of grade and subtype.
Conclusions: A quarter of all the operated primary kidney tumors were ≤ 4 cm. Smaller tumors were more likely to be benign and of lower stage. A cutoff size regarding biologic aggressiveness can be settled at the 3 cm size. The PN rate increased along the decade. Grade and subtype reporting rates remained suboptimal, although a positive trend was noted.