IS ADRENALECTOMY A NECESSARY COMPONENT OF RADICAL NEPHRECTOMY? UCLA EXPERIENCE WITH 511 RADICAL NEPHRECTOMIES

Abstract

We determine the incidence and characteristics of adrenal involvement in localized and advanced renal cell carcinoma, and evaluate the role of adrenalectomy as part of radical nephrectomy. The records of 511 patients undergoing radical nephrectomy with ipsilateral adrenalectomy for renal cell carcinoma at our medical center between 1986 and 1998 were reviewed. Mean patient age was 63.2 years (range 38 to 85), and 78% of the subjects were males and 22% were females. Patients were divided into subgroups of 164 with localized (stage T1-2 tumor, group 1) and 347 with advanced (stage T3-4N01M01, group 2) renal cell carcinoma. Staging of tumors was performed according to the 1997 TNM guidelines. A retrospective review of preoperative computerized tomography (CT) of the abdomen was performed. Radiographic findings were subsequently compared to postoperative histopathological findings to assess the predictive value of tumor characteristics and imaging in determining adrenal metastasis. Of the 511 patients 29 (5.7%) had adrenal involvement. Average size of the adrenal tumor was 3.86 cm. (standard deviation 1.89). Tumor stage correlated with probability of adrenal spread, with T4, T3 and T1-2 tumors accounting for 40%, 7.8% and 0.6% of cases, respectively. Upper pole intrarenal renal cell carcinoma most likely to spread was local extension to the adrenal glands, representing 58.6% of adrenal involvement. In contrast, multifocal, lower pole and mid region renal cell carcinoma tumors metastasized hematogenously, representing 32%, 7% and 4% of adrenal metastasis, respectively. The relationship between intrarenal tumor size (mean 8.9 cm., range 3 to 17) and adrenal involvement (independent of stage) was not statistically significant. Renal vein thrombus involvement was demonstrated in 8 of 12 cases (67%) with left and 2 of 9 (22%) with right adrenal involvement. Preoperative CT demonstrated 99.6% specificity, 99.4% negative predictive value, 89.6% sensitivity and 92.8% positive predictive value for adrenal involvement by renal cell carcinoma. With a low incidence of 0.6%, adrenal involvement is not likely in patients with localized, early stage renal cell carcinoma and adrenalectomy is unnecessary, particularly when CT is negative. In contrast, the 8.1% incidence of adrenal involvement with advanced renal cell carcinoma supports the need for adrenalectomy. Careful review of preoperative imaging is required to determine the need for adrenalectomy in patients at increased risk with high stage lesions, renal vein thrombus and upper pole or multifocal intrarenal tumors. With a negative predictive value of 99.4%, negative CT should decrease the need for adrenalectomy. In contrast, positive findings are less reliable given the relatively lower positive predictive value of this imaging modality. Although such positive findings may raise suspicion of adrenal involvement, they may not necessarily indicate adrenalectomy given the low incidence, unless renal cell carcinoma with risk factors, such as high stage, upper pole location, multifocality and renal vein thrombus, is present.