Urological Oncology Comparative Analysis of Radiologically Measured Size and True Size of Renal Tumors

Purpose: We evaluated the differences between radiologically measured size and patho-logic size of renal tumors. Materials and Methods: The data from 171 patients who underwent radical or partial nephrectomy for a renal tumor at Ajou University Hospital were reviewed. Radiologic tumor size, which was defined as the largest diameter on a computed tomographic scan, was compared with pathologic tumor size, which was defined as the largest diameter on gross pathologic examination. Results: Mean radiologic size was significantly larger than mean pathologic size for all tumors (p=0.019). When stratified according to radiologic size range, mean radio-logic size was significantly larger than mean pathologic size for tumors ＜4 cm (p=0.003), but there was no significant difference between the sizes for tumors 4–7 cm and ＞7 cm. When classified according to histologic subtype, mean radiologic size was significantly larger than mean pathologic size only in clear cell renal cell carcinomas (p=0.002). When classified according to tumor location, mean radiologic size was sig-nificantly larger than mean pathologic size in endophytic tumors (p=0.043) but not in exophytic tumors. When endophytic tumors were stratified according to radiologic size range, there was a significant difference between the mean radiologic and pathologic sizes for tumors ＜4 cm (p=0.001) but not for tumors 4–7 cm (p=0.073) and ＞7 cm (p=0.603). Conclusions: Our results suggest that in planning a nephron-sparing surgery for renal tumors, especially for endophytic tumors of less than 4 cm, the tumor size measured on a computed tomography scan should be readjusted to get a more precise estimate of the tumor size