Long-Term Follow-up of Dose-Adapted and Reduced-Field Radiotherapy With or Without Chemotherapy for Central Nervous System GerminomaPage 1449
A. W. Jensen, N. N. Issa Laack, J. C. Buckner, P. J. Schomberg, C. J. Wetmore, and P. D. Brown
This article studies the role of chemotherapy and reduced dose- and field-size radiotherapy in central nervous system germinoma. Although early reports were encouraging, long-term follow-up reveals some important findings. Neoadjuvant chemotherapy and local-field radiation results in a long-term failure rate of nearly 20%, primarily marginal or ventricular, which is unsettling when no recurrences were seen in patients treated with larger radiation fields. This data suggests chemotherapy allows for reduction of total dose of radiotherapy, but does not provide adequate treatment of the region at highest-risk for recurrence with localized radiotherapy, the ventricular system.
Radiation-Induced Cancers from Modern Radiotherapy Techniques: Intensity-Modulated Radiotherapy Versus Proton TherapyPage 1477
M. Yoon, S. H. Ahn, J. Kim, D. H. Shin, S. Y. Park, S. B. Lee, K. H. Shin, and K. H. Cho
There is a concern that proton beam therapy (PBT) may have a higher risk of radiation-induced secondary cancers than x-ray therapy due to the number of neutrons produced by the scattering of proton beams. In this study, we compared the secondary radiation dose distribution resulting from PBT and IMRT treatment in patients with prostate and head and neck cancers. We found that the estimated secondary cancer risk in PBT was either significantly lower than in IMRT or that, at least, secondary cancer risk of PBT did not exceed that of conventional IMRT.
The Effects of G2-Phase Enrichment and Checkpoint Abrogation on Low-Dose Hyper-RadiosensitivityPage 1509
S. A. Krueger, G. D. Wilson, E. Piasentin, M. C. Joiner, and B. Marples
This article examines the underlying mechanisms of hyper-radiosensitivity (HRS), a response that defines the extreme sensitivity of cells to low doses of ionizing radiation. It is known that HRS cell killing involves the evasion of damage detection and repair processes leading to death by apoptosis. The current study demonstrates that the expression of HRS reflects the progression of G2-phase cells into mitosis in a dose dependent manner, and that this can be influenced by specific inhibitors of cell proliferation. The data indicate the potential of modulating HRS by manipulating the transition of radiation-damaged G2 phase cells into mitosis.
Online Adaptive Replanning Method for Prostate RadiotherapyPage 1561
E. E. Ahunbay, C. Peng, S. Holmes, A. Godley, C. Lawton, and X. A. Li
“This article describes an online adaptive replanning for the prostate cancer radiotherapy where the original treatment plan is quickly modified, instead of optimized from scratch, to adapt the anatomy of the day. The online replanning can be accomplished within a reasonable time frame (minutes), comparable to the time frames for IGRT. This is a retrospective study that demonstrates that significant dosimetric improvement can be achieved by the newly developed quick online replanning method in terms of both target coverage and/or organ sparing (e.g. 13% increase in the minimum prostate dose).”
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