Smaller renal tumors are more likely to be benign or be a lower grade of malignancy. T1 renal tumors are more likely to be detected incidentally than T2 tumors. When T1 incidental and symptomatic tumors were compared, there was no difference between the malignancy rates. However, when T2 incidental and symptomatic tumors were compared, symptomatic tumors were more likely to be high grade malignancy.
Ureteroscopy and shock wave lithotripsy were associated with high success and low complication rates. However, shock wave lithotripsy required significantly less operating time, was more often performed on an outpatient basis, and showed a trend towards less flank pain and dysuria, fewer complications and quicker convalescence. Patient satisfaction was uniformly high in both groups. Although ureteroscopy and shock wave lithotripsy are highly effective for treatment of distal ureteral stones, we believe that HM3 shock wave lithotripsy, albeit slightly more costly, is preferable to manipulation with ureteroscopy since it is equally efficacious, more efficient and less morbid.
IMPORTANCE
Early detection of small asymptomatic kidney tumors presages better patient outcome. Incidental discovery of asymptomatic renal tumors by abdominal imaging is expensive and cannot reliably distinguish benign from malignant tumors.
OBJECTIVE
This investigation evaluated the clinical utility, sensitivity and specificity of urine aquaporin-1 (AQP1) and perilipin-2 (PLIN2) concentrations as unique noninvasive biomarkers to diagnose malignant clear cell or papillary renal cell carcinoma (RCC) in a screening paradigm.
DESIGN, SETTING, AND PARTICIPANTS
Urine samples were obtained from 720 patients undergoing routine abdominal CT (screening population), 80 healthy controls and 19 patients with pathologically confirmed RCC. Urine AQP1 and PLIN2 concentrations were measured by sensitive and specific ELISA and Western blot procedures, respectively.
MAIN OUTCOMES AND MEASURES
AQP1 and PLIN2 were measured prospectively in a screening paradigm in an otherwise asymptomatic population. The absence or presence of a renal mass and of RCC, were verified by abdominal computed tomography (CT) and by post-nephrectomy pathologic diagnosis, respectively.
RESULTS
Median urine AQP1 and PLIN2 concentrations in patients with known RCC were more than 12-fold higher (P<0.0001 each) than controls and the screening population. The area under the receiver operating characteristic curve for urine AQP1 and PLIN2 concentrations individually or in combination was ≥0.92, with ≥85% sensitivity and ≥87% specificity compared with control or screening patients. Three of the 720 screening patients had biomarker concentrations suggestive of RCC and were found to have an imaged renal mass by CT. Two patients, evaluated further, had RCC.
CONCLUSIONS AND RELEVANCE
These results demonstrate the clinical utility, specificity and sensitivity of urine AQP1 and PLIN2 to diagnose RCC. These novel tumor-specific proteins have high clinical validity and substantial potential as specific diagnostic and screening biomarkers for clear cell and papillary RCC, and in the differential diagnosis of imaged renal masses.
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