CyberKnife for Kidney Lesions

Stereotactic Radiosurgery/Stereotactic Body Radiotherapy for RCC

Radiosurgery and stereotactic body radiotherapy have been extensively applied against renal cell carcinoma (23-27). Paradoxically, although the response of metastatic RCC brain lesions to conventional radiotherapy has been virtually nil, the long-term response rate of RCC brain metastases to radiosurgery exceeds 90% in some series (24,25,26). The addition of conventional whole brain radiotherapy to stereotactic radiosurgery does not appear to improve the intracranial local control or recurrence-free survival in RCC patients with intracranial metastatic lesions (25,26).

Highly successful stereotactic radiotherapy results have been described for both primary and metastatic RCC all over the body by the Radiumhemmet group, with only 3 documented recurrences among 162 treated RCC lesions, using a variety of treatment regimens of 3-4 large stereotactic radiotherapy treatments (23). Similarly, spinal metastatic RCC lesions have been successfully radiosurgically ablated in a single treatment with CyberKnife® in 89% of cases, a figure that seems even more impressive when one considers that the majority of these lesions had already recurred after “conventional” spinal radiotherapy prior to their CyberKnife® radiosurgical treatment (27).

In summary, it appears that RCC is far more sensitive to ablative (1-5 treatments using large dose per treatment) radiotherapy/radiosurgery approaches than it is to “conventionally fractionated” radiotherapy (10-30 smaller radiation treatments).

Precise Ablation of Focal Kidney Lesions

The kidney is another organ that moves with respiration, limiting the accuracy of conventional or even stereotactic radiotherapy approaches against malignant lesions within the kidney itself, resulting in a large fuzzy margin between the high dose and low dose radiotherapy zone. This seriously limits the ability to safely delivery an ablative radiation regimen to a primary kidney lesion, even with sophisticated radiotherapy techniques.

CyberKnife® Synchrony® Respiratory Tracking System overcomes this problem by locking onto implanted gold fiducial markers that are easily placed within the kidney under CT guidance, and correlates their position with the respiratory cycle as determined by optical tracking, tracking the targeted lesion with 1.5 mm accuracy throughout the entire breathing cycle. This allows a much smaller applied margin compared with other radiation delivery systems – virtually surgical in its precision.

Targeting Angles

Traditional radiotherapy systems target the lesion from a relatively small number of fixed positions. In contrast the CyberKnife® device allows literally hundreds of targeting angles to be selected, increasing the ability to conform the ablative dose to the target lesion within the kidney, while better sparing the adjacent kidney and surrounding normal gastrointestinal tissues.

The accuracy of this model has been validated in a study of pig kidneys, in live animals treated with CyberKnife® radiosurgery, whose kidneys were then evaluated pathologically, revealing total destruction of all cellular elements within the focally targeted zone by 8 weeks post-treatment, with preserved kidney tissue adjacent to the sharply marginated target zone annihilation.


Treatment of renal cell carcinoma (RCC) is highly successful in early stage cases and sometimes results in prolonged disease-free survival even in patients with metastatic lesions (1-6). There is a trend toward kidney sparing surgery in patients with small tumors, and increasing use of nonsurgical ablative approaches (1,3,4,5, 7-11).

While there is some evidence that RCC is “resistant” to conventional radiotherapy doses (14), particularly for brain lesions (12,13,16), there is a substantial body of literature demonstrating local control rates in excess of 90% for renal cell carcinoma lesions targeted with stereotactic radiosurgery or large dose per treatment (hypofractionated) stereotactic radiotherapy (23-27).

As the only system capable of tracking respiratory-induced moving targets such as the kidney with radiosurgical precision, CyberKnife® appears uniquely capable of ablating focal tumor lesions within the kidney itself, in RCC patients for whom surgery is not an option (28).  Due to its robust dose sculpting and target tracking capability, CyberKnife® radiosurgery is also appropriately applied to ablate a range of locally recurrent, unresectable and metastatic RCC lesions (23-27).

Case Studies:

Spinal Cord Metastasis (L-1 from Renal Cell Carcinoma)
Peter Gerszten, M.D., Steve Burton, M. D. - UPMC
Posterior Fossa Metastatic Renal Cell Carcinoma
Debra Freeman, M.D., Paul D. Dernbach, M.D. - NCH


  1. Lee VT, Yip SK, Tan PH, Siow WY, Lau WK, Cheng CW. Renal cell carcinoma of 4 cm or less: an appraisal of its clinical presentation and contemporary surgical management. Asian J Surg. 2006 Jan;29(1):40-3
  2. Canfield SE, Kamat AM, Sanchez-Ortiz RF, Detry M, Swanson DA, Wood CG. Renal cell carcinoma with nodal metastases in the absence of distant metastatic disease (clinical stage TxN1-2M0): the impact of aggressive surgical resection on patient outcome. J Urol. 2006 Mar;175(3 Pt 1):864-9
  3. Konety BR, Lam JS, Shvarts O, Leppert JT, Pantuck AJ, Figlin RA, Belldegrun AS. Postoperative surveillance protocol for patients with localized and locally advanced renal cell carcinoma based on a validated prognostic nomogram and risk group stratification system. Urol Oncol. 2006 Jan-Feb;24(1):87-8
  4. Becker F, Siemer S, Humke U, Hack M, Ziegler M, Stockle M. Elective Nephron Sparing Surgery Should Become Standard Treatment for Small Unilateral Renal Cell Carcinoma: Long-term Survival Data of 216 Patients.Eur Urol. 2006 Feb;49(2):308-13.
  5. Phelan MW, Perry KT, Gore J, Schulam PG. Laparoscopic partial nephrectomy and minimally invasive nephron-sparing surgery.Curr Urol Rep. 2003 Feb;4(1):13-20.
  6. Murthy SC, Kim K, Rice TW, Rajeswaran J, Bukowski R, DeCamp MM, Blackstone EH. Can we predict long-term survival after pulmonary metastasectomy for renal cell carcinoma? Ann Thorac Surg. 2005 Mar;79(3):996-1003
  7. Gervais DA, McGovern FJ, Arellano RS, McDougal WS, Mueller PR. Radiofrequency ablation of renal cell carcinoma: part 1, Indications, results, and role in patient management over a 6-year period and ablation of 100 tumors. AJR Am J Roentgenol. 2005 Jul;185(1):64-71
  8. Gervais DA, Arellano RS, McGovern FJ, McDougal WS, Mueller PR. Radiofrequency ablation of renal cell carcinoma: part 2, Lessons learned with ablation of 100 tumors. AJR Am J Roentgenol. 2005 Jul;185(1):72-80.
  9. Merkle EM, Nour SG, Lewin JS. MR imaging follow-up after percutaneous radiofrequency ablation of renal cell carcinoma: findings in 18 patients during first 6 months. Radiology. 2005 Jun;235(3):1065-71
  10. Ahrar K, Matin S, Wood CG, Wallace MJ, Gupta S, Madoff DC, Rao S, Tannir NM, Jonasch E, Pisters LL, Rozner MA, Kennamer DL, Hicks ME. Percutaneous radiofrequency ablation of renal tumors: technique, complications, and outcomes. J Vasc Interv Radiol. 2005 May;16(5):679-88
  11. Lee DI, McGinnis DE, Feld R, Strup SE. Retroperitoneal laparoscopic cryoablation of small renal tumors: intermediate results. Urology. 2003 Jan;61(1):83-8.
  12. Halperin EC, Harisiadis L. The role of radiation therapy in the management of metastatic renal cell carcinoma. Cancer. 1983 Feb 15;51(4):614-7.
  13. Wronski M, Maor MH, Davis BJ, Sawaya R, Levin VA. External radiation of brain metastases from renal carcinoma: a retrospective study of 119 patients from the M. D. Anderson Cancer Center. Int J Radiat Oncol Biol Phys. 1997 Mar 1;37(4):753-9.
  14. DiBiase SJ, Valicenti RK, Schultz D, Xie Y, Gomella LG, Corn BW. Palliative irradiation for focally symptomatic metastatic renal cell carcinoma: support for dose escalation based on a biological model. J Urol. 1997 Sep;158(3 Pt 1):746-9.
  15. Lee J, Hodgson D, Chow E, Bezjak A, Catton P, Tsuji D, O'Brien M, Danjoux C, Hayter C, Warde P, Gospodarowicz MK. A phase II trial of palliative radiotherapy for metastatic renal cell carcinoma. Cancer. 2005 Nov 1;104(9):1894-900
  16. Cannady SB, Cavanaugh KA, Lee SY, Bukowski RM, Olencki TE, Stevens GH, Barnett GH, Suh JH. Results of whole brain radiotherapy and recursive partitioning analysis in patients with brain metastases from renal cell carcinoma: a retrospective study. Int J Radiat Oncol Biol Phys. 2004 Jan 1;58(1):253-8.
  17. Rost A, Brosig W. Preoperative irradiation of renal cell carcinoma. Urology. 1977 Nov;10(5):414-7.
  18. Malkin RB. Regression of renal carcinoma following radiation therapy. J Urol. 1975 Nov;114(5):782-3.
  19. Frydenberg M, Gunderson L, Hahn G, Fieck J, Zincke H. Preoperative external beam radiotherapy for locally advanced primary or recurrent renal malignancies. J Urol. 1994 Jul;152(1):15-21.
  20. Peeling WB, Mantell BS, Shepheard BG. Post-operative irradiation in the treatment of renal cell carcinoma. Br J Urol. 1969 Feb;41(1):23-31
  21. Aref I, Bociek RG, Salhani D. Is post-operative radiation for renal cell carcinoma justified? Radiother Oncol. 1997 May;43(2):155-7
  22. Kao GD, Malkowicz SB, Whittington R, D'Amico AV, Wein AJ. Locally advanced renal cell carcinoma: low complication rate and efficacy of postnephrectomy radiation therapy planned with CT. Radiology. 1994 Dec;193(3):725-30.
  23. Wersall PJ, Blomgren H, Lax I, Kalkner KM, Linder C, Lundell G, Nilsson B, Nilsson S, Naslund I, Pisa P, Svedman C. Extracranial stereotactic radiotherapy for primary and metastatic renal cell carcinoma. Radiother Oncol. 2005 Oct;77(1):88-95
  24. Noel G, Valery CA, Boisserie G, Cornu P, Hasboun D, Marc Simon J, Tep B, Ledu D, Delattre JY, Marsault C, Baillet F, Mazeron JJ. LINAC radiosurgery for brain metastasis of renal cell carcinoma. Urol Oncol. 2004 Jan-Feb;22(1):25-31
  25. Sheehan JP, Sun MH, Kondziolka D, Flickinger J, Lunsford LD. Radiosurgery in patients with renal cell carcinoma metastasis to the brain: long-term outcomes and prognostic factors influencing survival and local tumor control. J Neurosurg. 2003 Feb;98(2):342-9.
  26. Goyal LK, Suh JH, Reddy CA, Barnett GH. The role of whole brain radiotherapy and stereotactic radiosurgery on brain metastases from renal cell carcinoma. Int J Radiat Oncol Biol Phys. 2000 Jul 1;47(4):1007-12
  27. Gerszten PC, Burton SA, Ozhasoglu C, Vogel WJ, Welch WC, Baar J, Friedland DM. Stereotactic radiosurgery for spinal metastases from renal cell carcinoma. J Neurosurg Spine. 2005 Oct;3(4):288-95
  28. Ponsky LE, Crownover RL, Rosen MJ, Rodebaugh RF, Castilla EA, Brainard J, Cherullo EE, Novick AC. Initial evaluation of CyberKnife® technology for extracorporeal renal tissue ablation. Urology. 2003 Mar;61(3):498-501

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