Unacceptable Cosmesis in a Protocol Investigating Intensity Modulated Radiotherapy with Active Breathing Control for Accelerated Partial Breast IrradiationPage 71
R. Jagsi, M. A. Ben-David, J. M. Moran, R. B. Marsh, K. A. Griffith, J. A. Hayman, L.J. Pierce
This article reports cosmetic results and toxicity from a prospective study evaluating accelerated partial-breast irradiation (APBI). Patients received 38.5 Gy in 3.85 Gy fractions bid with a beamlet IMRT technique at deep-inspiration breath hold. Thirty-four patients were enrolled. With a median follow-up of 2.5 years, new unacceptable cosmesis developed in 7 patients, leading to early study closure. Therefore, the hypofractionated schedule and parameters commonly used for external beam APBI may be suboptimal when highly conformal techniques with management of breathing motion are used. The V50 and V100 of the breast seem correlated with cosmetic outcome, and stricter limits may be appropriate in this setting.
Margin on Gross Tumor Volume and Risk of Local Recurrence in Head and Neck CancerPage 164
J. J. Caudell, R. F. Meredith, S. A. Spencer, K.S. Keene, M.C. Dobelbower, J. A. Bonner
Little data is available regarding appropriate margins on the gross tumor volume of head and neck cancers. The current analysis retrospectively examined the margins utilized for intensity modulated radiotherapy and correlated those with locoregional control. Anatomical and volumetric expansions resulted in similar locoregional control. Patients with a total gross tumor volume to planning target volume volumetric expansion of 1.5 cm or less had similar locoregional control as those with larger expansions. These data may help physicians select an appropriate method of determining tumor volumes treated with intensity modulated radiotherapy.
Distinct Signaling Pathways Following Higher or Lower Doses of Radiation in Three Close-Related Human Lymphoblast Cell LinesPage 212
This article reports radiation-induced transcriptional responses in human lymphoblastoid lines with differing p53 status. We determined whether distinct signaling pathways are triggered after higher (10 Gy) or lower (at D0: 0.81-1.50 Gy) doses of radiation. At the 10 Gy, the p53 signaling pathway played a pivotal role in cells with functional p53, whereas in cells without p53 NFkB appeared to replace p53 function. In contrast, E2F4 seemed to play a dominant role independent of p53 status after lower doses. This study elucidates the impacts of transcription factors p53, NFkB, and E2F4 in response to higher or lower doses of radiation.
Volumetric Modulated Arc Therapy Improves Dosimetry And Reduces Treatment Time Compared To Conventional Intensity Modulated Radiotherapy For Locoregional Radiotherapy Of Left-Sided Breast Cancer Including The Internal Mammary NodesPage 287
C.C. Popescu, I.A. Olivotto, W.A. Beckham, W. Ansbacher, S. Zavgorodni, R. Shaffer, E. S. Wai, K. Otto,
Volumetric modulated arc therapy (VMAT) enables radiation treatment to be efficiently and precisely delivered to left-sided breast cancer patients with nodal involvement that are difficult to treat with conventional techniques or multi-field intensity modulated radiotherapy (IMRT). This is achieved by continuously varying treatment machine parameters such as multileaf collimator positions, dose rate and gantry angle.
In this dosimetric study, VMAT proved to halve the treatment time compared with IMRT without compromising breast and regional nodes dose coverage and with better sparing of ipsilateral lung and heart. This would contribute to greater patient comfort and improved throughput.
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