Stereotactic ablative body radiation therapy for primary kidney cancer: a 3-dimensional conformal technique associated with low rates of early toxicity

Int J Radiat Oncol Biol Phys. 2014 Dec 1;90(5):1061-8. doi: 10.1016/j.ijrobp.2014.07.043. Epub 2014 Oct 13.

Abstract

Purpose: 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 and materials: 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.

Conclusion: 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.

Trial registration: ClinicalTrials.gov NCT01676428.

Publication types

  • Clinical Trial, Phase I
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Carcinoma, Renal Cell / pathology
  • Carcinoma, Renal Cell / surgery*
  • Feasibility Studies
  • Female
  • Humans
  • Kidney Neoplasms / pathology
  • Kidney Neoplasms / surgery*
  • Male
  • Middle Aged
  • Organs at Risk / radiation effects
  • Prospective Studies
  • Radiosurgery / adverse effects
  • Radiosurgery / methods*
  • Radiotherapy Dosage
  • Radiotherapy Planning, Computer-Assisted / adverse effects
  • Radiotherapy Planning, Computer-Assisted / methods*
  • Time Factors
  • Tumor Burden

Associated data

  • ClinicalTrials.gov/NCT01676428