970 MULTIFOCAL RENAL CELL CARCINOMA IN CANDIDATES FOR PARTIAL NEPHRECTOMY

CONCLUSIONS been detectable, thus leaving a true unknown incidence of 69l.l This 6% rate comes close to the observed 5% or less local recurrence rate found in 2 large clinical partial nephrectomy series (reference 12 in article).2 In the Cleveland Clinic study the local recurrence rate was as low as 1 in 95 patients (1.lTo for stage 1 and unilateral disease

we encountered a high incidence of unsuspected multifocal renal cancer in patients Otherwise have been 'Onsidered good candidates for partial nephrectomy. This high incidence of multifocality was independent of tumor size but did appear occur at increased frequency with advanc- ing tumor stage (T3A or greater). However, many surgeons consider the patient with a small exophytic tumor (stage T3A) an ideal candidate for partial nephrectomy, since there

reference 12 in article), m i s number is identical to the incidence of renal cell cancer developing in the contralateral kidney.3

The authors note that pathological information does not seem to be a reliable method of predicting multifocality, although Kletscher et al showed tha t papillary and mixed histological patterns were sig-

is little need for dissection deep within the renal paren- chma. It is recommended that partial nephrectomy be re-

nificantly associated with multifocality.' I agree that there is an ongoing controversy about the distinction between renal adenomas

served for patients who require nephron preservation and that partial nephrectomy not be simply because it is technically feasible.

and small renal cell adenocarcinomas independent of the previous statements of Bell (reference 10 in article). According to Farrow at my institution, there is a clear distinction between these 2 entities. Adenomas are small and often found in the subcapsular portion of the kidney. They consist of densely packed tubules lined by small regular cuboidal cells with rounded uniform nuclei lacking any cy- tological anaplasia. There is no mitotic activity, they are well cir- cumscribed and the interphase with normal renal parenchyma lacks sigxnficant inflammation or stromal reaction, which one could expect with a malignant tumor. Some of the small tumors may feature a predominance of papillary structures and may contain psam- momatous Apart from oncocytomas, which usually show benign behavior, a carcinoma can be anaplastic or i t can have hypernephroid features that consist usually of lipid-laden clear cells and can be considered malignant irrespective of size. A papillary carcinoma is distinguished by the presence of nuclear anaplasia consistent with a malignant tumor. In the opinion of Farrow, the relationship of corticoadenoma to carcinoma is unknown and there has been no report of a benign tubular corticoadenoma developing

Thus, as long as there is considerable confusion in regard to the histopathological determination of a tumor (adenoma versus carci- noma) the numbers for incidence in regard to multifocality may vary widely depending on the interpretation of our pathological col- leagues. However, for the time being, the low long-term local recur- rence rates observed after partial nephrectomy for low grade, low stage disease encourage many of us to continue to recommend partial nephrectomy for well selected patients (reference 12 in article)." This is also supported by the clinical experience of several of the large institutional experiences ~ o r l d w i d e . ~ , ~ Indeed, partial nephrectomy for low grade (2 degrees or less) and stage (P2 or less) renal cell cancer can be as effective as radial nephrectomy.:'

REFERENCES

1. Vermooten, V.: Indications for conservative surgery in certain tumors: a study based On the growth pattern Of the 'Iear

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incidental finding. J. Urol., 134: 1094, 1985. 4. Mein, E. A. and Novick, A. ,-: Partial nephrectomy for renal cell

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Catalona, L. I. Lipshultz and E, J, McGuire. st. Louis: Mosby Year Book, Inc., chapt. 1, pp. 1-9, 1992.

5. ~ a ~ ~ ~ l , E., ~ ~ f i ~ h ~ ~ k ~ , M,, ~ ~ ~ ~ l ~ ~ i ~ , D. and servadio, c,: Incidental small renal tumors accompanying clinically overt into a carcinoma. renal cell carcinoma. J. Urol., 140 22, 1988.

6. Cheng, w, s., Farrow, G. M, and Zincke, H.: The incidence of mdticentricity in renal cell carcinoma, J, ur0l., 146: 1221, 1991.

7. Novick, A. C., Streem, S., Montie, J. E., Po*s, J. E., Siegel, s., Montague, D. V. and Goormastic, M.: Conservative surgery for renal cell carcinoma: a single-center with 100 pa- tients. J. Urol., 141: 835, 1989.

8. Wieland, D., Sutherland, D. E. R., Chavers, B., Simmons, R. L., hcher , N. L, ~ ~ j a r i ~ ~ , J. s,: Information of 628 living related kidney donors at a single institution, with long-term follow-up in 472 cases. Transplant. Proc., 1 6 5, 1984.

9. Murphy, G. P. and Mostofi, F. K: Histologic assessment and clinical prognosis of renal adenoma. J. Urol., 103: 31, 1970.

10. Bell, E. T.: A classification of renal tumors with observations on the frequency of the various types. J. Urol., 3 9 238, 1938.

11. Fisher, E. R. and Horvat, B.: Comparative ultrastructural study of so-called renal adenoma and carcinoma. J. Urol., 108: 382, 1972.

12. Licht, M. R., Novick, A. C. and Goormastic, M.: Nephron sparing surgery in incidental versus suspected renal cell carcinoma. J. Urol., 152: 39, 1994.

13. Zincke, H. and Blute, M. L.: Renal tumors. J. Urol., 152: 43, 1994.

14. Kletscher, B. A., Qian, J., Bostwick, D. G., Andrews, P. E. and Zincke, H.: Prospective analysis of multifocal renal cell carci- noma (RCC): influence of histologic pattern, grade, stage, number, volume and DNA ploidy. J. Urol., part 2, 151: 314A, abstract 348, 1994.

3' KoMack' J. w' and Grossman' H' B.: carcinoma as an

Horst Zincke Department of Urology Mayo Clinic Rochester, Minnesota

1. Kletscher, B. A,, Qian, J., Bostwick, D. G., Andrews, P. E. and Zincke, H.: Prospective analysis of multifocality in renal cell carcinoma: influence of histological pattern, grade, number, size, volume and deoxyribonucleic acid ploidy. J. Urol., part 2, 1 5 3 904, 1995.

renal-conserving surgery for renal cell carcinoma: experience in 104 patients and extended followup. J. Urol., 144: 852,1990.

3. Hawkins, C. A., Wollan, p, c,, Grabner, A, and Zincke, H,: Disease outcome in patients (pts) with low-grade (521, low- stage (5T2) renal cell cancer (RCC) is similar when treated by nephron-preserving (CSx) or radical surgery 1 RSx). J. Ur& part 2, 151: 261A. abstract 133, 1994.

EDITORIAL COMMENT 4. Steinbach. F.. Stockle. M.. Muller. J . W.. Thiiroff. S. w.,

2. M ~ ~ ~ ~ ~ , w, R. and Zincke, H.: progression and survival

This prospective radical nephrectomy study of 44 patients set out to determine the incidence of multifocality in those with renal cell cancer whose primary tumor is 10 cm. or less in diameter. Of the patients 11 125%) had radiographically unsuspected multifocal renal cell cancer but 8 of these 11 had a stage of pT3a or greater. This high multifocality rate leads the authors to recommend caution in the decision to perform partial nephrectomy for renal cell cancer. This studv on multifocalitv is different from that reoorted bv others show-

5.

~ 1 ~ ~~~~~ , - . - , . Melchior, S. W.. Stein, R. and Hohenfellner, R.: Conservative surgery of renal cell tumors in 140 patients: 21 years OfeXPe- rience. J. Urol., 148: 24, 1992.

Moll, V., Becht, E. and Ziegler, M.: Kidney preserving surgery in renal cell tumors: indications, techniques and results in 152 patients. J. Urol., 150: 319, 1993.

REPLY BY AUTHORS ~~ <~

T h e Editorial Comment does not differ significantly from t he conclusion of our report. The Comment states t h a t partial nephrectomy should be offered to "well selected patients." We concluded t h a t partial nephrectomy should be reserved for patients who require nephron preservation and tha t partial

ing an incidence of 7% (reference 6 in article). 16%' and 19.7fJ (reference 5 in article) among 100, 100 and 69 patients, respectively. M ~ ~ , in the study by metscher et al multifocality on preoperative imaging studies could be verified in 44% ofthe patients and standard examination of the kidney at operation would have revealed an additional 19%. for a total of 63% whose multifocality would have