International journal of radiation oncology, biology, physics
-
Int. J. Radiat. Oncol. Biol. Phys. · May 2016
Comparative StudyInitial Report of a Prospective Dosimetric and Clinical Feasibility Trial Demonstrates the Potential of Protons to Increase the Therapeutic Ratio in Breast Cancer Compared With Photons.
To compare dosimetric endpoints between proton therapy (PT) and conventional radiation and determine the feasibility of PT for regional nodal irradiation (RNI) in women with breast cancer. ⋯ Proton therapy for RNI after mastectomy or BCT significantly improves cardiac dose, especially for left-sided patients, and lung V5 and V20 in all patients without excessive acute toxicity. Proton therapy simultaneously improves target coverage for the internal mammary nodes and level 2 axilla, which may positively impact long-term survival in breast cancer patients.
-
Int. J. Radiat. Oncol. Biol. Phys. · May 2016
Incidence of CNS Injury for a Cohort of 111 Patients Treated With Proton Therapy for Medulloblastoma: LET and RBE Associations for Areas of Injury.
Central nervous system (CNS) injury is a rare complication of radiation therapy for pediatric brain tumors, but its incidence with proton radiation therapy (PRT) is less well defined. Increased linear energy transfer (LET) and relative biological effectiveness (RBE) at the distal end of proton beams may influence this risk. We report the incidence of CNS injury in medulloblastoma patients treated with PRT and investigate correlations with LET and RBE values. ⋯ Central nervous system and brainstem injury incidence for PRT in this series is similar to that reported for photon radiation therapy. The risk of CNS injury was higher for whole posterior fossa boost than for involved field. Although no clear correlation with RBE values was found, numbers were small and additional investigation is warranted to better determine the relationship between injury and LET.
-
Int. J. Radiat. Oncol. Biol. Phys. · May 2016
A Prospective Outcomes Study of Proton Therapy for Chordomas and Chondrosarcomas of the Spine.
To evaluate the effectiveness of definitive or adjuvant external beam proton therapy on survival in patients with chordomas and chondrosarcomas of the spine. ⋯ High-dose proton therapy controls more than half of spinal chordomas and chondrosarcomas and compares favorably with historic photon data. Local progression is the dominant mode of treatment failure and may be reduced by treating patients at the time of initial diagnosis. The impact of age is a novel finding of this study.
-
Int. J. Radiat. Oncol. Biol. Phys. · May 2016
Clinical TrialFive-Year Biochemical Results, Toxicity, and Patient-Reported Quality of Life After Delivery of Dose-Escalated Image Guided Proton Therapy for Prostate Cancer.
To report clinical outcomes in patients treated with image guided proton therapy (PT) for localized prostate cancer. ⋯ Image guided PT provided excellent biochemical control rates for patients with localized prostate cancer. The actuarial rates of high-grade toxicity were low after PT. From pretreatment to 5 years of follow-up, a significant decline was found only in mean EPIC sexual summary scores. Prospective clinical studies are needed to determine the comparative effectiveness of PT and other radiation treatment strategies.
-
Int. J. Radiat. Oncol. Biol. Phys. · May 2016
Comparative StudyCan We Advance Proton Therapy for Prostate? Considering Alternative Beam Angles and Relative Biological Effectiveness Variations When Comparing Against Intensity Modulated Radiation Therapy.
For prostate treatments, robust evidence regarding the superiority of either intensity modulated radiation therapy (IMRT) or proton therapy is currently lacking. In this study we investigated the circumstances under which proton therapy should be expected to outperform IMRT, particularly the proton beam orientations and relative biological effectiveness (RBE) assumptions. ⋯ If either a fixed RBE of 1.1 or a variable RBE model could be validated in vivo, then it would always be possible to use AO IMPT to dose-boost the prostate and improve normal tissue sparing relative to IMRT. For a cohort without rectum spacer gels, this study (1) underlines the importance of resolving the question of proton RBE within the framework of an IMRT versus proton debate for the prostate and (2) highlights that without further LET/RBE model validation, great care must be taken if AO proton fields are to be considered for prostate treatments.