International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2004
A dynamic supraclavicular field-matching technique for head-and-neck cancer patients treated with IMRT.
The conventional single-isocenter and half-beam (SIHB) technique for matching supraclavicular fields with head-and-neck (HN) intensity-modulated radiotherapy (IMRT) fields is subject to substantial dose inhomogeneities from imperfect accelerator jaw/MLC calibration. It also limits the isocenter location and restricts the useful field size for IMRT. We propose a dynamic field-matching technique to overcome these limitations. ⋯ Compared with the conventional SIHB technique, the dynamic field-matching technique provides superior dose homogeneity in the abutment region between the supraclavicular and HN IMRT fields. The dynamic feathering mechanism substantially reduces dose inhomogeneities that result from imperfect jaw/MLC calibration. In addition, isocenter location in the dynamic field-matching technique can be chosen for reproducible patient setup and for adequate IMRT field size rather than being dictated by the match position. It also allows angling of the supraclavicular field to reduce the volume of healthy lung irradiated, which is impractical with the SIHB technique. In principle, this technique should be applicable to any treatment site that requires the abutment of static and intensity-modulated fields.
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2004
Concurrent weekly cisplatin and radiotherapy in routine management of cervical cancer: a report on patient compliance and acute toxicity.
To evaluate patient compliance and acute toxicity accompanying concurrent weekly cisplatin and radiotherapy (RT) in the routine management of cervical cancer. ⋯ Our results show that pelvic RT combined with weekly cisplatin in cervical cancer patients is accompanied by considerable acute toxicity. Furthermore, a number of patients were unable to comply with the treatment schedule owing to reasons unrelated to treatment toxicity. Thus, administration of the full chemotherapy dose may be difficult, although the delivery of planned RT was generally not compromised. Additional follow-up is needed to assess the late toxicity of combined modality treatment.
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2004
Time course of serum cytokines in patients receiving proton or combined photon/proton beam radiation for resectable but medically inoperable non-small-cell lung cancer.
We prospectively measured the levels of basic fibroblast growth factor (bFGF), tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, IL-10, and procollagen III peptide (P III P) in serum from non-small-cell lung cancer patients treated with photons combined with protons or protons alone. These factors were quantified because they may be extremely important in the development of side effects, and the treated volume integral dose may be crucial in inducing them. ⋯ Although significant changes occurred in some of the measured cytokines and P III P, it was the difference in the volume integral dose that occurred when protons were used alone vs. mixed photon/proton therapy that correlated with the incidence of pneumonitis and/or fibrosis. However, it cannot be ruled out that differences in cytokine levels before radiotherapy initiation may have contributed to the outcome.
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2004
Changes in temporal patterns of local failure after breast-conserving therapy and their prognostic implications.
The purpose of this analysis was to evaluate patterns and rates of ipsilateral breast tumor recurrence (IBTR) over time based on the type of failure (true recurrence/marginal miss [TR/MM] vs. elsewhere [E]) and to compare these to rates of contralateral failure in women with Stages I/II breast cancer treated with conservative surgery (CS) and radiation therapy (RT). ⋯ The rates and patterns of IBTR vary with time and, after 5 years, approach the rates of development of a contralateral breast cancer. E failures are, overall, less frequent than TR/MM but contribute increasingly to the IBTR rate after 5 years. Time to tumor recurrence is the most reliable predictor of prognosis after IBTR.
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Int. J. Radiat. Oncol. Biol. Phys. · Oct 2004
Interaction of amifostine and ionizing radiation on transcriptional patterns of apoptotic genes expressed in human microvascular endothelial cells (HMEC).
Amifostine is a prodrug that requires dephosphorylation by alkaline phosphatase to become activated. This process occurs rapidly within the bloodstream after its i.v. administration to patients undergoing cancer treatment with selected radiation and chemotherapies. Vascular endothelial cells will, therefore, represent a normal cell system that is among the first to experience the radioprotective effects of this agent. Amifostine's active free thiol WR-1065 was investigated to determine its effect on radiation-induced changes in transcriptional patterns and subsequent apoptosis in human microvascular endothelial cells (HMEC) growing in vitro. ⋯ WR-1065, the active thiol form of amifostine, is an effective radioprotector of HMEC as determined by use of clonogenic and apoptotic assays for cell survival. Expression profiling successfully defined the transcriptional response of HMEC to both WR-1065 and ionizing radiation exposure, either alone or in combination, and demonstrated both synergistic and antagonistic effects on the expression of different cellular genes, along with corresponding functional responses. The radioprotective effects of amifostine are not limited to its well-characterized physiochemical properties, which include free-radical scavenging, auto-oxidation leading to intracellular hypoxia, and chemical repair by hydrogen atom donation, but include its ability to modulate the complex transcriptional regulation of genes that are involved in apoptosis, cell cycle, and DNA repair.