title: Stereotactic ablative body radiation therapy for primary kidney cancer: a 3-dimensional conformal technique associated with low rates of early toxicity.
abstract: OBJECTIVE
  To describe our 3-dimensional conformal planning approaches and report early toxicities with stereotactic body radiation therapy for the management of primary renal cell carcinoma.
  
  
  METHODS
  This is an analysis of a phase 1 trial of stereotactic body radiation therapy for primary inoperable renal cell carcinoma. A dose of 42 Gy/3 fractions was prescribed to targets ≥5 cm, whereas for <5 cm 26 Gy/1 fraction was used. All patients underwent a planning 4-dimensional CT to generate a planning target volume (PTV) from a 5-mm isotropic expansion of the internal target volume. Planning required a minimum of 8 fields prescribing to the minimum isodose surrounding the PTV. Intermediate dose spillage at 50% of the prescription dose (R50%) was measured to describe the dose gradient. Early toxicity (<6 months) was scored using the Common Terminology Criteria for Adverse Events (v4.0).
  
  
  RESULTS
  From July 2012 to August 2013 a total of 20 patients (median age, 77 years) were recruited into a prospective clinical trial. Eleven patients underwent fractionated treatment and 9 patients a single fraction. For PTV targets <100 cm(3) the median number of beams used was 8 (2 noncoplanar) to achieve an average R50% of 3.7. For PTV targets >100 cm(3) the median beam number used was 10 (4 noncoplanar) for an average R50% value of 4.3. The R50% was inversely proportional to decreasing PTV volume (r=-0.62, P=.003) and increasing total beams used (r=-0.51, P=.022). Twelve of 20 patients (60%) suffered grade ≤2 early toxicity, whereas 8 of 20 patients (40%) were asymptomatic. Nausea, chest wall pain, and fatigue were the most common toxicities reported.
  
  
  CONCLUSIONS
  A 3-dimensional conformal planning technique of 8-10 beams can be used to deliver highly tolerable stereotactic ablation to primary kidney targets with minimal early toxicities. Ongoing follow-up is currently in place to assess long-term toxicities and cancer control.
authors.affiliation: Department of Radiotherapy Services, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Department of Medical Imaging and Radiation Sciences, Monash University, Melbourne, Victoria, Australia. Electronic address: daniel.pham@petermac.org.
authors.forename: Daniel
authors.initials: D
authors.lastname: Pham
authors.affiliation: Department of Radiotherapy Services, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
authors.forename: Ann
authors.initials: A
authors.lastname: Thompson
authors.affiliation: Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Sir Peter MacCallum Department of Oncology, Melbourne University, Melbourne, Victoria, Australia.
authors.forename: Tomas
authors.initials: T
authors.lastname: Kron
authors.affiliation: Sir Peter MacCallum Department of Oncology, Melbourne University, Melbourne, Victoria, Australia; Department of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
authors.forename: Farshad
authors.initials: F
authors.lastname: Foroudi
authors.affiliation: Department of Medical Imaging and Radiation Sciences, Monash University, Melbourne, Victoria, Australia.
authors.forename: Michal Schneider
authors.initials: MS
authors.lastname: Kolsky
authors.affiliation: Department of Radiotherapy Services, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
authors.forename: Thomas
authors.initials: T
authors.lastname: Devereux
authors.affiliation: Department of Radiotherapy Services, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Lim
authors.affiliation: Sir Peter MacCallum Department of Oncology, Melbourne University, Melbourne, Victoria, Australia; Department of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
authors.forename: Shankar
authors.initials: S
authors.lastname: Siva
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000473:pathology / Q000601:surgery*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D058958:Organs at Risk / Q000528:radiation effects; D011446:Prospective Studies; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000009:adverse effects / Q000379:methods*; D013997:Time Factors; D047368:Tumor Burden