Comparison Of Radiographic And Pathologic Sizes Of Renal Tumors

Main Category: Urology / Nephrology
Also Included In: Cancer / Oncology;  Radiology / Nuclear Medicine
Article Date: 28 Mar 2010 - 0:00 PDT


UroToday.com - The selection of appropriate candidates for partial nephrectomy, open, laparoscopic, or robotic, along with modern ablative therapies and active surveillance has been largely guided by the renal tumor sizes assessed via various imaging modalities.

Accordingly, radiographic size of tumor remains an important factor in the era of minimal invasive treatment approaches as the treatment options for renal lesions are continued to be contemplated based upon longstanding assumptions that radiographic and pathologic tumor sizes are equivalent. Surely, a difference of only a millimeter in radiologic and pathologic tumor size can alter patients' status regarding tumor stage and outlook for prognosis. Also, such discrepancy, if indeed present, may well result in inadvertent exclusion of a significant number of patients from having opportunity to receive nephron-sparing surgeries.

In our study, it was observed that although actual size of renal mass can be generally overestimated by CT images, differences may be minimal and clinically insignificant in most cases. Meanwhile, for tumors measured to be 4 to < 5 cm on CT, we observed a significant overestimation of pathologic tumor size as reported by others. Previously, such phenomenon was mentioned as having clinical significance since 4-cm cutoff has long been applied for selection of candidates for partial nephrectomy. Meanwhile, despite the statistical significance, observed difference in sizes for tumors in 4 to < 5 cm range was only about 2 mm in our study.

Furthermore, the indication for partial nephrectomy is currently expanding, and recent reports have suggested that partial nephrectomy can be safely performed for tumors sized up to 7 cm. Accordingly, we believe that radiographic overestimation of size for renal tumors in 4 to < 5 cm range may be of less clinical significance today than has previously been suggested.

The limitations of our study may include the fact that our study was retrospective, and thus we could not control for the timing of imaging before surgical resection of renal lesions. Still, unlike in other similar studies previously reported, CT scans were obtained within 4 weeks before the surgery using the same technique in all of our subjects. Also, the same uro-radiologists participated in the review of imagings from all cases included in our study and the situation was the same for pathologic analyses of specimens. Thus, we believe that our data would be additive to the existing literature.

Written by Sung Kyu Hong, MD, PhD as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations, etc., of their research by referencing the published abstract.

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