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Cryotherapy for Renal Cell Carcinoma and Angiomyolipoma
0022-5347W1551-0252803.MI10
Vol. 155,252-255. January 1% Printed in U . S q
THE JOLIWAL OF UROLDCY Copyright 0 1996 by AMERICAN UROLOCICAL ASSOCIATION. INC
Urologists At Work CRYOTHERAPY FOR RENAL CELL CARCINOMA AND ANGIOMYOLIPOMA MARK G. DELWORTH, LOUIS L. PISTERS," BRUNO D. FORNAGE ANDREW C. VON ESCHENBACH
AND
From the Departments of Urology and Diagnostic Radiology, University of T e r n M.D. Anderson Cancer Center, Houston, Texas
ABSTRACT
Purpose: We determined the feasibility of renal cryotherapy in humans. Materials and Methods: Two patients with tumors in a solitary kidney were treated with renal cryotherapy . Results: Both patients tolerated renal cryotherapy well with no change in renal function and no postoperative complications. Conclusions: Cryoablation of select renal lesions can be performed safely with minimal loss of renal function. KEYWORDS: cryosurgery; carcinoma, renal cell; kidney neoplasms; lipoma
The development of new cryosurgical technology has led to nitrogen is circulated through the probes until -7OC is a reevaluation of its usefulness in the field of urology. Thin reached so that they would adhere to the tissue. The probes percutaneous probes, refined multiport cryosurgical units are suspended from and over a hanging retractor. The freezing process is initiated by circulation of liquid and high resolution ultrasound have prompted the use of cryosurgical ablation of the prostate at many centers, with nitrogen through the probes, which reached a temperature of reports of excellent tumor destruction. Others have used -18OC. As in the prostate, the development of frozen tissue similar techniques for destruction of liver tumors. Given that produces an internal echogenic rim with attenuation of the this method effectively destroys tumors, we explored the use ultrasound and an anechoic black zone beyond which a dense of cryotherapy for the treatment of multifocal renal cell car- white rim is produced due to "through shadowing" (fig. 1, B). cinoma and a large angiomyolipoma in 2 patients with a The ultrasound probe is carefully maneuvered around the solitary kidney. surface of the kidney to observe the ice ball formation deep within the kidney. As the freezing process migrates toward the surface, the zone of frozen tissue becomes palpable, and MATERIALS AND METHODS The technique of renal cryoablation used was similar for closer to the surface visible changes are noted as the tissue both patients. After vigorous preoperative hydration the in- freezes. Once the ice ball has encompassed the tumor and an apvolved kidney is exposed through a flank incision. The renal artery is exposed and a vessel loop is passed around it for propriate margin of normal tissue, the probes are changed to occlusion if required. Mannitol and furosemide are adminis- the thaw cycle until the ice ball resolves completely. During tered intravenously. With the kidney mobilized, a 7.5 MHz. the thaw cycle, the previously frozen area becomes soft and sterile, linear array, T-shaped ultrasound probe is used to blue colored due to subcapsular hemorrhage, which is limited to the area of the freeze. A second complete freeze-thaw cycle identify the lesions. Because of the size of the larger tumor in case 1we elected is then performed, since recent data have shown a 92% negto use 3 cryoprobes with overlapping freeze zones to provide ative biopsy rate following prostate cryoablation using the optimal coverage for this lesion. A n 18 gauge, diamond- double-freeze technique.' As the probes and sheaths are retipped needle with obturator is placed under real-time ultra- moved, small tubular strips of absorbable gelatin sponge are sound guidance through the kidney into the lesion. The ob- placed in each sheath for hemostasis. In case 1 the same turator is removed and a 0.038 J-hook guide wire is inserted technique was then used to ablate the smaller lesion, except through the lumen of the needle. ARer confirming placement that only 1probe was necessary. of the guide wire by ultrasound, a dilator with sheath is placed over it into the lesion using ultrasound monitcring to CASE HISTORIES assure that the tip of the obturator is at the deepest margin Case 1. A 31-year-old Hispanic man with stage TlNOMO of the tumor. The guide wire and dilator are removed. Two renal cell carcinoma underwent right radical nephrectomy in other sheaths are placed via a similar technique such that July 1993. Contrast-enhanced computerized tomography the entire tumor volume along with a 1.0 to 1.5cm. margin of (CT) 15 months later revealed a 2 x 3 cm. lesion superolatnormal kidney is encompassed by the freezing process (fig. 1, to a 2 X 2 cm.lesion in the mid portion of the left kidney A). With the kidney stabilized, the 3 mm. cryoprobes are eral 2, A and B). Arteriography revealed these tumors to be (fig. placed into the sheaths under ultrasound guidance. Liquid hypervascular and no metastases were detected. We considered enucleation but were concerned about the risk of local Accepted for publication July 21, 1995. uesta for reprints: Department of Urology-Box 110, Univer- recurrence due to inadequate margins. Although the risk of aiG%%exas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., clinical recurrence is slight after enucleation? invasion of the Houston, Texas 77030. pseudocapsule and surrounding tissues is common and has 252
CRYOTHERAPY FOR RENAL CELL CANCER AND ANGIOMYOLIPOMA
253
FIG. 1. A, placement from left to right of 0.038 guide wire, sheath with 3 mm. cryoprobe and sheath within larger tumor. B, formation of ice ball by cryoprobe. Note echogenic interface between tumorhenal parenchyma and ice hall, resulting in dramatic posterior shadowing.
FIG. 2. Case 1.A and B , CT shows 2 x 2 cm. and 2 x 2 cm. lesions in leR kidney. C, MRI of largest tumor bed 1 month postoperatively reveals area of necrosis decreased in size consistent with resorption and scamng.
254
CRYOTHERAPY FOR RENAL CELL CANCER AND ANGIOMYOLIPOMA
therapy in urology. The application of cryosurgery to the prostate7.8 and live+' has been well described, and is currently performed at multiple medical centers. Renal cryosurgery has been described in the dog model with a n excellent correlation between the ultrasound and pathological measurements of the cryosurgical lesions caused by the freezing process, indicating the potential to obtain reliable margins around the t u m ~ r . ~ . ~ The treatment of renal tumors in patients with a solitary kidney presents the challenge of eradicating all disease while preserving renal function. In our 2 patients cryoablation appeared to have this possible advantage. Cryosurgical ablation was performed with minimal blood loss, no immediate complications, a short postoperative recovery period and minimal loss of renal parenchyma, as evidenced by a serum creatinine level of 1.3 mg./dl. at hospital discharge in both patients with a solitary kidney. Sonographically, the margins of the cryosurgical lesions extended a t least 1 cm. beyond FIG.3. Case 2. CT demonstrates 7 x 10 cm. angiomyolipoma in those of the renal cell carcinomas, and MRI 1month after the procedure demonstrated a decrease in the size of the lesions upper pole of right kidney. consistent with resorption of the necrotic tumors and surrounding margins. been reported in 4 0 8 of the cases.3 We also considered partial nephrectomy but believed that for excision of both mid renal masses with a 1 cm. margin of normal tissue approximately 50 to 60%,of the renal parenchyma would have to be resected. Excision of greater than 504 renal parenchyma and excision of tumor in a solitary kidney have been shown to increase the risk of postoperative renal failure.' We offered renal cry* therapy as an experimental nephron-sparing operation because its feasibility has been demonstrated in preclinical animal models.5.6 Total operative time was 3.5 hours and estimated blood loss was 200 cc. A closed suction drain was placed in the perinephric space and removed on postoperative day 2 after minimal drainage was noted (lessthan 20 cc in 8 hours). The patient was discharged from the hospital 5 days postoperatively with a creatinine level of 1.3 mgJdl. Magnetic resonance imaging (MRI) 2 days after cryosurgery revealed hemorrhagic necrosis in the tumor beds. Followup MRI 1 month later demonstrated a significant decrease in the hemorrhagic necrosis consistent with resorption (fig. 2, C). Case 2. A 32-year-old white man with a history of severe tuberous scleroais and bilateral renal angiomyolipoma underwent left radical nephrectomy in 1993 following severe hemorrhage from a 22 cm. renal angiomyolipoma. (The brother, also diagnosed with tuberous sclerosis, died of a massive hemorrhage originating in a renal angiomyolipoma.) Contraat-enhanced CT 8 months after nephrecbmy revealed an enlarging 7 x 10 cm.right upper pole angiomyolipoma (fig. 3).The patient experienced intermittent right flank pain and gross hematuria. Partial nephreetomy was not done because greater than 508 of normal parenchyma would need to be excised. placing the patient at significant risk for postoperative renal failure.' Selective embolization and antiangiogenic medical therapy were also considered. The patient chose experimental nephron-sparing renal cryotherapy. Total operative time was 4.5 hours and estimated blood loss was 700 cc. Two closed suction drains were left in the perinephric space. and removed on postoperative days 2 and 3 after minimal drainage was noted (less than 30 cc in 8 hours). The patient was discharged home 5 days postoperatively with a creatinine level of 1.3 mgJdl. Followup CT 3 months after cryoablation revealed a 10% enlargement in the size of the angiomyolipoma. DISCUSSlON
Cryosurgery is not a new concept but the advent of improved probee. cryosurgical freezing apparatus and ultrasound monitoring devices has led to a resurgence of this
CONCLUSIONS
We believe this to be the first report of cryosurgery for renal tumors in humans. It would appear that cryoablation of renal lesions can be performed safely with minimal loss of functioning renal parenchyma. Further studies are warranted to assess the usefulness of cryosurgery for renal tumors. REFERENCES
1. von Eschenbach, A. C., Pisters, L. L., Swanson, D. A,, Babaian, R. J., Dinney, C. P. N. and Evans, R. B.: Results of a phase I/II study of cryoablation for recurrent carcinoma of the prostate: the University of Texas M. D. Anderson Cancer Center experience. J. Urol., part 2, 163: 5034 abstract 1097,1995. 2. Novick, A. C., Zincke, H., Neves, R.J. and Topley, H. M.: Surgical enucleation for renal cell carcinoma. J. Urol., 135 235, 1986. 3. Marshall, F.F.,Taxy,J. B., Fishman, E. K and Chang, R.: The feasibility of surgical enucleation for renal cell carcinoma. J. Urol., 136 231,1986. 4. Campbell, S.C., Novick, A. C., Streem, S. B., Klein, E. and Light, M.: Complications of nephron sparing surgery for renal tumors. J. Urol., 161: 1177,1994. 5. Stephenson, R.A., King, D. and Rohr, R. L.: Renal cryoablation in a canine model. J. Urol., part 2, 153: 403A, abstract 700, 1995. 6. Onik, G.M., Reyes, G., Cohen, J. K and Porterfield, B.: Ultrasound characteristics of renal cryosurgery. Urology, 42: 212, 1993. 7. Onik,G.M., Cohen, J. K, Reyes, G. D., Rubinsky, B., Chang. Z. and Baust, J.: Transrectal ultrasound-guided percutaneous radical cryosurgical ablation of the prostate. Cancer, 72: 1291, 1993. 8. Miller, R. J., Jr.. Cohen, J. K. and Merlotti, L. A.:Percutaneous transperineal cryosurgical ablation of the prostate for the pnmary treatment of clinical stage C adenocarcinoma of the prostate. Urology,44: 170,1994. 9. Morris, D. L., Horton. M. D., Dilley, A. V., Warlters, A. and Clingan, P. R.: Treatment of hepatic metastases by cryotherapy and regional Cytotoxic perfusion. Gut, 34: 1156,1993. EDITORIAL COMMENTS The authors used cryotherapy to treat 2 patients with renal cell carcinoma and angiomyolipoma, respectively. involving a solitary kidney. Attempted cryotherapeutic management of a benign tumor, such as angiomyolipoma, is biologically safe and should not preclude subsequent conventional therapy if necessary. Cryotherapeutic management of a young patient with surgically treatable localized r e d cell carcinoma. as described in case 1, is a more troublesome issub This patient presented with 2 small (less than 3 cm.) renal d
CRYOTHEWY FOR RENAL CELL CANCER AND ANGIOMYOLIPOMA carcinomas involving a solitary kidney that could have been removed completely with a surrounding margin of normal tissue and preservation of at least two-thirds of the kidney. The risk of permanent renal failure requiring chronic dialysis in this setting is approximately 5% (reference 4 in article). Since cryotherapy represents an experimental undertaking in this setting, how assured can one be that there is no remaining viable renal cell carcinoma within the kidney? Emerging data on cryotherapy for prostate cancer demonstrate a definite incidence of locally recurrent (or persistent) malignancy within the treated organ. Notwithstanding the technical feasibility of renal cryotherapy in animal models, to my knowledge there are no clinical data relative to treatment of patients with renal cell carcinoma and its use in this setting must certainly be considered experimental. The long-term curative and functional efficacy of classical nephron-sparing surgery for renal cell carcinoma is well established,' and this procedure should be done preferentially in technically amenable cases. Andrew C. Novick Department of Urology Cleveland Clinic Foundation Cleveland, Ohio
1. Licht, M., Novick, A. C. and Goormastic, M.: Nephron-sparing surgery in incidental versus suspected renal cell carcinoma. J. Urol., 162 39, 1994. The concept of renal cryotherapy for tumors is interesting. Nevertheless, the indication for such a technique in a 32-year-old man with 2 relatively small and superficial tumors in a solitary kidney is hazardous. In the experimental study of Stephenson et al (reference 5 in article) only normal renal parenchyma was frozen on the kidney surface in a small series of 6 dogs. Ultrasonographic artifact of the frozen area and physical measurement of the cryosurgical lesion were not compared completely in all animals, and in 2 (33%) the difference was approximately 3 to 5 mm. In the absence of any experimental information on the efficacy of cryotherapy of renal tumors, how can the authors be certain of complete tumor cell destruction in this case? A preliminary study performed on patients with both kidneys seems necessary. Removal of the frozen lesion with the kidney could demonstrate the actual effect of cryotherapy
255
on renal tumors without risk to the patient. Remembering a report on dissemination of a nondiagnosed renal cancer after percutaneous nephrolithotomy and knowing the 5% risk of a wound gr& after laparoscopic colectomy, how can the authors be sure to avoid such risks with manipulation of the seeds? A 1-month followupis too short in oncological practice. Finally, appropriate surgical resection of renal cancer during partial nephrectomy in patients with a solitary kidney, performed by skilled urologists and followed by trained pathologists, results in a low risk of dialysis and offers the best chance of survival.l.* Strict protocols must be defined before seeds are placed in any renal tumor, particularly those in a solitary kidney. Innovation must not be confused with excitation. Guy Vallancien Department of Urology C.M.C. de la Porte de Choisy Paris, France
1. Novick, A. C., Streem, S., Montie, J. E., Pontes, J. E., Siegel, S., Montague, D. K and Goormastic, M.: Conservative surgery for renal cell carcinoma: a single-center experience with 100 patients. J. Urol., 141: 835, 1989. 2. Provet, J., Tessler, A, Brown,J., Golimbu, M., Bosniak,M. and Morales, P.: Partial nephrectomy for renal cell carcinoma: indications, results and implications. J. Urol., 14b:472,1991. REPLY BY AUTHORS At our institution partial nephreetomy remains the treatment of choice for patients with tumors in a solitary kidney. We have used cryotherapy exclusively in a highly select group of patients in whom we believed classic nephron sparing surgery would be a high risk. Based on our limited experience we think that cryotherapy for patients with multifocal complex central lesions may potentially be less morbid than standard nephmn sparing surgery. Because of ita proved safety and efficacy, nephmn sparing surgery should remain standard therapy for most tumors in solitary kidneys. We wish to emphasize that renal cryotherapy is currently experimental and should only be considered in highly select patients in whom nephmn sparing surgery would be technically difficult with a higher risk of complications.
Vol. 155,252-255. January 1% Printed in U . S q
THE JOLIWAL OF UROLDCY Copyright 0 1996 by AMERICAN UROLOCICAL ASSOCIATION. INC
Urologists At Work CRYOTHERAPY FOR RENAL CELL CARCINOMA AND ANGIOMYOLIPOMA MARK G. DELWORTH, LOUIS L. PISTERS," BRUNO D. FORNAGE ANDREW C. VON ESCHENBACH
AND
From the Departments of Urology and Diagnostic Radiology, University of T e r n M.D. Anderson Cancer Center, Houston, Texas
ABSTRACT
Purpose: We determined the feasibility of renal cryotherapy in humans. Materials and Methods: Two patients with tumors in a solitary kidney were treated with renal cryotherapy . Results: Both patients tolerated renal cryotherapy well with no change in renal function and no postoperative complications. Conclusions: Cryoablation of select renal lesions can be performed safely with minimal loss of renal function. KEYWORDS: cryosurgery; carcinoma, renal cell; kidney neoplasms; lipoma
The development of new cryosurgical technology has led to nitrogen is circulated through the probes until -7OC is a reevaluation of its usefulness in the field of urology. Thin reached so that they would adhere to the tissue. The probes percutaneous probes, refined multiport cryosurgical units are suspended from and over a hanging retractor. The freezing process is initiated by circulation of liquid and high resolution ultrasound have prompted the use of cryosurgical ablation of the prostate at many centers, with nitrogen through the probes, which reached a temperature of reports of excellent tumor destruction. Others have used -18OC. As in the prostate, the development of frozen tissue similar techniques for destruction of liver tumors. Given that produces an internal echogenic rim with attenuation of the this method effectively destroys tumors, we explored the use ultrasound and an anechoic black zone beyond which a dense of cryotherapy for the treatment of multifocal renal cell car- white rim is produced due to "through shadowing" (fig. 1, B). cinoma and a large angiomyolipoma in 2 patients with a The ultrasound probe is carefully maneuvered around the solitary kidney. surface of the kidney to observe the ice ball formation deep within the kidney. As the freezing process migrates toward the surface, the zone of frozen tissue becomes palpable, and MATERIALS AND METHODS The technique of renal cryoablation used was similar for closer to the surface visible changes are noted as the tissue both patients. After vigorous preoperative hydration the in- freezes. Once the ice ball has encompassed the tumor and an apvolved kidney is exposed through a flank incision. The renal artery is exposed and a vessel loop is passed around it for propriate margin of normal tissue, the probes are changed to occlusion if required. Mannitol and furosemide are adminis- the thaw cycle until the ice ball resolves completely. During tered intravenously. With the kidney mobilized, a 7.5 MHz. the thaw cycle, the previously frozen area becomes soft and sterile, linear array, T-shaped ultrasound probe is used to blue colored due to subcapsular hemorrhage, which is limited to the area of the freeze. A second complete freeze-thaw cycle identify the lesions. Because of the size of the larger tumor in case 1we elected is then performed, since recent data have shown a 92% negto use 3 cryoprobes with overlapping freeze zones to provide ative biopsy rate following prostate cryoablation using the optimal coverage for this lesion. A n 18 gauge, diamond- double-freeze technique.' As the probes and sheaths are retipped needle with obturator is placed under real-time ultra- moved, small tubular strips of absorbable gelatin sponge are sound guidance through the kidney into the lesion. The ob- placed in each sheath for hemostasis. In case 1 the same turator is removed and a 0.038 J-hook guide wire is inserted technique was then used to ablate the smaller lesion, except through the lumen of the needle. ARer confirming placement that only 1probe was necessary. of the guide wire by ultrasound, a dilator with sheath is placed over it into the lesion using ultrasound monitcring to CASE HISTORIES assure that the tip of the obturator is at the deepest margin Case 1. A 31-year-old Hispanic man with stage TlNOMO of the tumor. The guide wire and dilator are removed. Two renal cell carcinoma underwent right radical nephrectomy in other sheaths are placed via a similar technique such that July 1993. Contrast-enhanced computerized tomography the entire tumor volume along with a 1.0 to 1.5cm. margin of (CT) 15 months later revealed a 2 x 3 cm. lesion superolatnormal kidney is encompassed by the freezing process (fig. 1, to a 2 X 2 cm.lesion in the mid portion of the left kidney A). With the kidney stabilized, the 3 mm. cryoprobes are eral 2, A and B). Arteriography revealed these tumors to be (fig. placed into the sheaths under ultrasound guidance. Liquid hypervascular and no metastases were detected. We considered enucleation but were concerned about the risk of local Accepted for publication July 21, 1995. uesta for reprints: Department of Urology-Box 110, Univer- recurrence due to inadequate margins. Although the risk of aiG%%exas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., clinical recurrence is slight after enucleation? invasion of the Houston, Texas 77030. pseudocapsule and surrounding tissues is common and has 252
CRYOTHERAPY FOR RENAL CELL CANCER AND ANGIOMYOLIPOMA
253
FIG. 1. A, placement from left to right of 0.038 guide wire, sheath with 3 mm. cryoprobe and sheath within larger tumor. B, formation of ice ball by cryoprobe. Note echogenic interface between tumorhenal parenchyma and ice hall, resulting in dramatic posterior shadowing.
FIG. 2. Case 1.A and B , CT shows 2 x 2 cm. and 2 x 2 cm. lesions in leR kidney. C, MRI of largest tumor bed 1 month postoperatively reveals area of necrosis decreased in size consistent with resorption and scamng.
254
CRYOTHERAPY FOR RENAL CELL CANCER AND ANGIOMYOLIPOMA
therapy in urology. The application of cryosurgery to the prostate7.8 and live+' has been well described, and is currently performed at multiple medical centers. Renal cryosurgery has been described in the dog model with a n excellent correlation between the ultrasound and pathological measurements of the cryosurgical lesions caused by the freezing process, indicating the potential to obtain reliable margins around the t u m ~ r . ~ . ~ The treatment of renal tumors in patients with a solitary kidney presents the challenge of eradicating all disease while preserving renal function. In our 2 patients cryoablation appeared to have this possible advantage. Cryosurgical ablation was performed with minimal blood loss, no immediate complications, a short postoperative recovery period and minimal loss of renal parenchyma, as evidenced by a serum creatinine level of 1.3 mg./dl. at hospital discharge in both patients with a solitary kidney. Sonographically, the margins of the cryosurgical lesions extended a t least 1 cm. beyond FIG.3. Case 2. CT demonstrates 7 x 10 cm. angiomyolipoma in those of the renal cell carcinomas, and MRI 1month after the procedure demonstrated a decrease in the size of the lesions upper pole of right kidney. consistent with resorption of the necrotic tumors and surrounding margins. been reported in 4 0 8 of the cases.3 We also considered partial nephrectomy but believed that for excision of both mid renal masses with a 1 cm. margin of normal tissue approximately 50 to 60%,of the renal parenchyma would have to be resected. Excision of greater than 504 renal parenchyma and excision of tumor in a solitary kidney have been shown to increase the risk of postoperative renal failure.' We offered renal cry* therapy as an experimental nephron-sparing operation because its feasibility has been demonstrated in preclinical animal models.5.6 Total operative time was 3.5 hours and estimated blood loss was 200 cc. A closed suction drain was placed in the perinephric space and removed on postoperative day 2 after minimal drainage was noted (lessthan 20 cc in 8 hours). The patient was discharged from the hospital 5 days postoperatively with a creatinine level of 1.3 mgJdl. Magnetic resonance imaging (MRI) 2 days after cryosurgery revealed hemorrhagic necrosis in the tumor beds. Followup MRI 1 month later demonstrated a significant decrease in the hemorrhagic necrosis consistent with resorption (fig. 2, C). Case 2. A 32-year-old white man with a history of severe tuberous scleroais and bilateral renal angiomyolipoma underwent left radical nephrectomy in 1993 following severe hemorrhage from a 22 cm. renal angiomyolipoma. (The brother, also diagnosed with tuberous sclerosis, died of a massive hemorrhage originating in a renal angiomyolipoma.) Contraat-enhanced CT 8 months after nephrecbmy revealed an enlarging 7 x 10 cm.right upper pole angiomyolipoma (fig. 3).The patient experienced intermittent right flank pain and gross hematuria. Partial nephreetomy was not done because greater than 508 of normal parenchyma would need to be excised. placing the patient at significant risk for postoperative renal failure.' Selective embolization and antiangiogenic medical therapy were also considered. The patient chose experimental nephron-sparing renal cryotherapy. Total operative time was 4.5 hours and estimated blood loss was 700 cc. Two closed suction drains were left in the perinephric space. and removed on postoperative days 2 and 3 after minimal drainage was noted (less than 30 cc in 8 hours). The patient was discharged home 5 days postoperatively with a creatinine level of 1.3 mgJdl. Followup CT 3 months after cryoablation revealed a 10% enlargement in the size of the angiomyolipoma. DISCUSSlON
Cryosurgery is not a new concept but the advent of improved probee. cryosurgical freezing apparatus and ultrasound monitoring devices has led to a resurgence of this
CONCLUSIONS
We believe this to be the first report of cryosurgery for renal tumors in humans. It would appear that cryoablation of renal lesions can be performed safely with minimal loss of functioning renal parenchyma. Further studies are warranted to assess the usefulness of cryosurgery for renal tumors. REFERENCES
1. von Eschenbach, A. C., Pisters, L. L., Swanson, D. A,, Babaian, R. J., Dinney, C. P. N. and Evans, R. B.: Results of a phase I/II study of cryoablation for recurrent carcinoma of the prostate: the University of Texas M. D. Anderson Cancer Center experience. J. Urol., part 2, 163: 5034 abstract 1097,1995. 2. Novick, A. C., Zincke, H., Neves, R.J. and Topley, H. M.: Surgical enucleation for renal cell carcinoma. J. Urol., 135 235, 1986. 3. Marshall, F.F.,Taxy,J. B., Fishman, E. K and Chang, R.: The feasibility of surgical enucleation for renal cell carcinoma. J. Urol., 136 231,1986. 4. Campbell, S.C., Novick, A. C., Streem, S. B., Klein, E. and Light, M.: Complications of nephron sparing surgery for renal tumors. J. Urol., 161: 1177,1994. 5. Stephenson, R.A., King, D. and Rohr, R. L.: Renal cryoablation in a canine model. J. Urol., part 2, 153: 403A, abstract 700, 1995. 6. Onik, G.M., Reyes, G., Cohen, J. K and Porterfield, B.: Ultrasound characteristics of renal cryosurgery. Urology, 42: 212, 1993. 7. Onik,G.M., Cohen, J. K, Reyes, G. D., Rubinsky, B., Chang. Z. and Baust, J.: Transrectal ultrasound-guided percutaneous radical cryosurgical ablation of the prostate. Cancer, 72: 1291, 1993. 8. Miller, R. J., Jr.. Cohen, J. K. and Merlotti, L. A.:Percutaneous transperineal cryosurgical ablation of the prostate for the pnmary treatment of clinical stage C adenocarcinoma of the prostate. Urology,44: 170,1994. 9. Morris, D. L., Horton. M. D., Dilley, A. V., Warlters, A. and Clingan, P. R.: Treatment of hepatic metastases by cryotherapy and regional Cytotoxic perfusion. Gut, 34: 1156,1993. EDITORIAL COMMENTS The authors used cryotherapy to treat 2 patients with renal cell carcinoma and angiomyolipoma, respectively. involving a solitary kidney. Attempted cryotherapeutic management of a benign tumor, such as angiomyolipoma, is biologically safe and should not preclude subsequent conventional therapy if necessary. Cryotherapeutic management of a young patient with surgically treatable localized r e d cell carcinoma. as described in case 1, is a more troublesome issub This patient presented with 2 small (less than 3 cm.) renal d
CRYOTHEWY FOR RENAL CELL CANCER AND ANGIOMYOLIPOMA carcinomas involving a solitary kidney that could have been removed completely with a surrounding margin of normal tissue and preservation of at least two-thirds of the kidney. The risk of permanent renal failure requiring chronic dialysis in this setting is approximately 5% (reference 4 in article). Since cryotherapy represents an experimental undertaking in this setting, how assured can one be that there is no remaining viable renal cell carcinoma within the kidney? Emerging data on cryotherapy for prostate cancer demonstrate a definite incidence of locally recurrent (or persistent) malignancy within the treated organ. Notwithstanding the technical feasibility of renal cryotherapy in animal models, to my knowledge there are no clinical data relative to treatment of patients with renal cell carcinoma and its use in this setting must certainly be considered experimental. The long-term curative and functional efficacy of classical nephron-sparing surgery for renal cell carcinoma is well established,' and this procedure should be done preferentially in technically amenable cases. Andrew C. Novick Department of Urology Cleveland Clinic Foundation Cleveland, Ohio
1. Licht, M., Novick, A. C. and Goormastic, M.: Nephron-sparing surgery in incidental versus suspected renal cell carcinoma. J. Urol., 162 39, 1994. The concept of renal cryotherapy for tumors is interesting. Nevertheless, the indication for such a technique in a 32-year-old man with 2 relatively small and superficial tumors in a solitary kidney is hazardous. In the experimental study of Stephenson et al (reference 5 in article) only normal renal parenchyma was frozen on the kidney surface in a small series of 6 dogs. Ultrasonographic artifact of the frozen area and physical measurement of the cryosurgical lesion were not compared completely in all animals, and in 2 (33%) the difference was approximately 3 to 5 mm. In the absence of any experimental information on the efficacy of cryotherapy of renal tumors, how can the authors be certain of complete tumor cell destruction in this case? A preliminary study performed on patients with both kidneys seems necessary. Removal of the frozen lesion with the kidney could demonstrate the actual effect of cryotherapy
255
on renal tumors without risk to the patient. Remembering a report on dissemination of a nondiagnosed renal cancer after percutaneous nephrolithotomy and knowing the 5% risk of a wound gr& after laparoscopic colectomy, how can the authors be sure to avoid such risks with manipulation of the seeds? A 1-month followupis too short in oncological practice. Finally, appropriate surgical resection of renal cancer during partial nephrectomy in patients with a solitary kidney, performed by skilled urologists and followed by trained pathologists, results in a low risk of dialysis and offers the best chance of survival.l.* Strict protocols must be defined before seeds are placed in any renal tumor, particularly those in a solitary kidney. Innovation must not be confused with excitation. Guy Vallancien Department of Urology C.M.C. de la Porte de Choisy Paris, France
1. Novick, A. C., Streem, S., Montie, J. E., Pontes, J. E., Siegel, S., Montague, D. K and Goormastic, M.: Conservative surgery for renal cell carcinoma: a single-center experience with 100 patients. J. Urol., 141: 835, 1989. 2. Provet, J., Tessler, A, Brown,J., Golimbu, M., Bosniak,M. and Morales, P.: Partial nephrectomy for renal cell carcinoma: indications, results and implications. J. Urol., 14b:472,1991. REPLY BY AUTHORS At our institution partial nephreetomy remains the treatment of choice for patients with tumors in a solitary kidney. We have used cryotherapy exclusively in a highly select group of patients in whom we believed classic nephron sparing surgery would be a high risk. Based on our limited experience we think that cryotherapy for patients with multifocal complex central lesions may potentially be less morbid than standard nephmn sparing surgery. Because of ita proved safety and efficacy, nephmn sparing surgery should remain standard therapy for most tumors in solitary kidneys. We wish to emphasize that renal cryotherapy is currently experimental and should only be considered in highly select patients in whom nephmn sparing surgery would be technically difficult with a higher risk of complications.