A Treatment Planning and Acute Toxicity Comparison of Two Pelvic Nodal Volume Delineation Techniques and Delivery Comparison of Intensity-Modulated Radiotherapy Versus Volumetric Modulated Arc Therapy for Hypofractionated High-Risk Prostate Cancer Radiotherapy
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario (Canada)
- Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario (Canada)
- Biostatistics Core, Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA (United States)
- Department of Radiation Oncology, University of California San Francisco, San Francisco, CA (United States)
Purpose: To perform a comparison of two pelvic lymph node volume delineation strategies used in intensity-modulated radiotherapy (IMRT) for high risk prostate cancer and to determine the role of volumetric modulated arc therapy (VMAT). Methods and Materials: Eighteen consecutive patients accrued to an ongoing clinical trial were identified according to either the nodal contouring strategy as described based on lymphotropic nanoparticle-enhanced magnetic resonance imaging technology (9 patients) or the current Radiation Therapy Oncology Group (RTOG) consensus guidelines (9 patients). Radiation consisted of 45 Gy to prostate, seminal vesicles, and lymph nodes, with a simultaneous integrated boost to the prostate alone, to a total dose of 67.5 Gy delivered in 25 fractions. Prospective acute genitourinary and gastrointestinal toxicities were compared at baseline, during radiotherapy, and 3 months after radiotherapy. Each patient was retrospectively replanned using the opposite method of nodal contouring, and plans were normalized for dosimetric comparison. VMAT plans were also generated according to the RTOG method for comparison. Results: RTOG plans resulted in a significantly lower rate of genitourinary frequency 3 months after treatment. The dosimetric comparison showed that the RTOG plans resulted in both favorable planning target volume (PTV) coverage and lower organs at risk (OARs) and integral (ID) doses. VMAT required two to three arcs to achieve adequate treatment plans, we did not observe consistent dosimetric benefits to either the PTV or the OARs, and a higher ID was observed. However, treatment times were significantly shorter with VMAT. Conclusion: The RTOG guidelines for pelvic nodal volume delineation results in favorable dosimetry and acceptable acute toxicities for both the target and OARs. We are unable to conclude that VMAT provides a benefit compared with IMRT.
- OSTI ID:
- 22056191
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 82, Issue 4; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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