eContour

71 yo female with medically inoperable, metastatic renal cell carcinoma, clear cell type with a large primary renal mass and oligometastases in the brain.

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Technique:

  • SBRT to the right renal tumor using VMAT
  • Dose painting to spare maximum normal kidney

Dose

  • 26 Gy in 1 fraction

Simulation

  • Supine with arms overhead, full-body vacbag with abdominal compression
  • Acquire a contrast enhanced 4D-CT scan encompassing all phases of respiration
  • NPO for at least 3 hours prior to CT to limit stomach/ bowel volumes.
  • Fuse CT with PET images focused on ipsilateral kidney.

 

Contours Per 

SBRT for treatment of medically inoperable primary renal cell carcinoma 

  • GTV includes the radiographic disease on the contrast CT and corroborated on fused PET images.
  • CTV with 2-3 mm margin into the renal parenchyma may be included if the tumor is not sharply defined / MRI imaging is not available.
  • ITV includes the extent of GTV / CTV on MIP images, including all phases of respiration on 4D CT.
  • PTV is 3- 5 mm margin on ITV depending on available Image guidance for treatment.

 

  • Many Renal cell cancer patients are medically inoperable or refuse surgery – historically these patients were managed with palliative intent, but recent studies show SBRT to primary kidney tumor to ablative doses is effective with >95% local control, especially for > 4 cm tumors. Treatment is safe with <1% grade 3 or higher toxicities.1
  • Acceptable prescription doses: 26 Gy in 1 fraction (<4 cm lesions), 42- 45 Gy in 3 fractions or 40 Gy in 5 fractions, depends on tumor size. Larger tumors > 7 cm in size can be treated in 5 fractions to a dose of 35 – 40 Gy depending on OAR constraints.2
  • OAR constraints (for 1 fraction SBRT): Bilateral kidneys 200 cc < 8.4 Gy, Liver 700 cc < 9.1 Gy, Stomach V11.2Gy < 10 cc, Small Bowel V11.9Gy < 5 cc, Large Bowel V14.3 Gy < 20 cc.3

References 

  1. Siva S, Ali M, Correa RJM, Muacevic A, Ponsky L, Ellis RJ, Lo SS, Onishi H, Swaminath A, McLaughlin M, Morgan SC, Cury FL, Teh BS, Mahadevan A, Kaplan ID, Chu W, Grubb W, Hannan R, Staehler M, Warner A, Louie AV. 5-year outcomes after stereotactic ablative body radiotherapy for primary renal cell carcinoma: an individual patient data meta-analysis from IROCK (the International Radiosurgery Consortium of the Kidney). Lancet Oncol. 2022 Dec;23(12):1508-1516. doi: 10.1016/S1470-2045(22)00656-8. Epub 2022 Nov 16. PMID: 36400098.
  2. Correa RJM, Rodrigues GB, Chen H, Warner A, Ahmad B, Louie AV. Stereotactic Ablative Radiotherapy (SABR) for Large Renal Tumors: A Retrospective Case Series Evaluating Clinical Outcomes, Toxicity, and Technical Considerations. Am J Clin Oncol. 2018 Jun;41(6):568-575. doi: 10.1097/COC.0000000000000329. PMID: 27635623.
  3. Pollom EL, Chin AL, Diehn M, et al. Normal Tissue Constraints for Abdominal and Thoracic Stereotactic Body Radiotherapy. Semin Radiat Oncol. 2017 Jul;27(3):197-208.doi: 10.1016/j.semradonc.2017.02.001. PMID: 28577827