Parameters Favorable to Intraprostatic Radiation Dose Escalation in Men With Localized Prostate Cancer

Journal Article · Wed Jun 01 00:00:00 EDT 2011 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2010.06.050· OSTI ID:21491784

Housri, Nadine; Ning, Holly; Ondos, John ^[1]; Choyke, Peter ^[2]; Camphausen, Kevin; Citrin, Deborah; Arora, Barbara; Shankavaram, Uma ^[1]; Kaushal, Aradhana ^[1]

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1. Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD (United States)
2. Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD (United States)

Purpose: To identify , within the framework of a current Phase I trial, whether factors related to intraprostatic cancer lesions (IPLs) or individual patients predict the feasibility of high-dose intraprostatic irradiation. Methods and Materials: Endorectal coil MRI scans of the prostate from 42 men were evaluated for dominant IPLs. The IPLs, prostate, and critical normal tissues were contoured. Intensity-modulated radiotherapy plans were generated with the goal of delivering 75.6 Gy in 1.8-Gy fractions to the prostate, with IPLs receiving a simultaneous integrated boost of 3.6 Gy per fraction to a total dose of 151.2 Gy, 200% of the prescribed dose and the highest dose cohort in our trial. Rectal and bladder dose constraints were consistent with those outlined in current Radiation Therapy Oncology Group protocols. Results: Dominant IPLs were identified in 24 patients (57.1%). Simultaneous integrated boosts (SIB) to 200% of the prescribed dose were achieved in 12 of the 24 patients without violating dose constraints. Both the distance between the IPL and rectum and the hip-to-hip patient width on planning CT scans were associated with the feasibility to plan an SIB (p = 0.002 and p = 0.0137, respectively). Conclusions: On the basis of this small cohort, the distance between an intraprostatic lesion and the rectum most strongly predicted the ability to plan high-dose radiation to a dominant intraprostatic lesion. High-dose SIB planning seems possible for select intraprostatic lesions.

• OSTI ID: 21491784
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Vol. 80, Issue 2; Other Information: DOI: 10.1016/j.ijrobp.2010.06.050; PII: S0360-3016(10)00905-3; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0360-3016
• Country of Publication: United States
• Language: English

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