International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 1998
The use of adaptive radiation therapy to reduce setup error: a prospective clinical study.
Adaptive Radiation Therapy (ART) is a feedback treatment process that optimizes a patient's treatment according to the patient specific information measured during the course of treatment. Utilizing an electronic portal imaging device (EPID) and a computer-controlled multileaf collimator (MLC), the ART process is currently being implemented in our clinic to improve the treatment accuracy by compensating for the treatment setup error. A prospective study was conducted to evaluate the feasibility and efficacy of the ART process for clinical use. ⋯ The prospective study demonstrates that the ART process can be effectively implemented in routine clinical practice to improve treatment accuracy. This process is also ready to be further extended to reoptimize the treatment plan by incorporating the predicted patient specific setup variation.
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 1998
Comparative StudyChanges in biochemical disease-free survival rates as a result of adoption of the consensus conference definition in patients with clinically localized prostate cancer treated with external-beam radiotherapy.
The optimal definition of biochemical recurrence of prostate cancer after definitive radiotherapy remains elusive. Different institutions have developed their own definitions, and a consensus conference (CC) sponsored by the American Society for Therapeutic Radiology and Oncology has recently proposed another definition. This study compares the definition previously used at our institution with the definition proposed by the CC. ⋯ The CPMC definition of two PSA increases can falsely identify patients as failures, particularly if the increases in PSA are small (i.e., < or = 0.3 ng/ml). The CC definition requiring three increases in PSA can falsely identify patients as disease-free when the time to failure is long relative to the follow-up time. We propose a that a definition that combines aspects of both definitions (two consecutive increases in PSA over 3 months, with a final value greater than 1.0 ng/ml and each increase being at least 0.3 ng/ml, or three consecutive increases) may be a better definition of biochemical failure.
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Int. J. Radiat. Oncol. Biol. Phys. · May 1998
The correlation between the ASTRO Consensus Panel definition of biochemical failure and clinical outcome for patients with prostate cancer treated with external beam irradiation. American Society of Therapeutic Radiology and Oncology.
We reviewed our institution's experience treating patients with external beam irradiation (RT) to determine if the ASTRO Consensus Panel definition of biochemical failure (BF) following radiation therapy correlates with clinical distant metastases free survival (DMFS), disease-free survival (DFS), cause-specific survival (CSS), and local control (LC). ⋯ The ASTRO Consensus Panel definition of BF following radiation therapy correlates well with clinical DMFS, DFS, and CSS. These findings suggest that the Consensus Panel definition may be a surrogate for clinical progression and survival and should be considered a valid endpoint for separating successful versus unsuccessful treatment. Additional studies with longer follow-up will be needed to corroborate these findings.
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Int. J. Radiat. Oncol. Biol. Phys. · May 1998
Randomized Controlled Trial Clinical TrialArtificial neural network model of survival in patients treated with irradiation with and without concurrent chemotherapy for advanced carcinoma of the head and neck.
This study was performed to investigate the feasibility of predicting survival in squamous cell carcinoma of the head and neck (SCCHN) with an artificial neural network (ANN), and to compare ANN performance with conventional models. ⋯ An ANN modeled 2-year survival in this data set more accurately than LR or staging models and employed predictive variables that could not be used by LR. Further work is planned to confirm these results on larger patient samples, examining longer follow-up to incorporate treatment type into the model.
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Int. J. Radiat. Oncol. Biol. Phys. · May 1998
Tumor size, irradiation dose, and long-term outcome of carcinoma of uterine cervix.
To assess the impact of tumor size and extent, and dose of irradiation on pelvic tumor control, incidence of distant metastases, and disease-free survival in carcinoma of the uterine cervix. ⋯ Clinical stage and size of tumor are critical factors in prognosis, therapy efficacy, and evaluation of results in carcinoma of the uterine cervix. The doses to point A suggest that for lesions <2 cm, doses of 75 Gy result in < or =10% pelvic failures, whereas in more extensive lesions, even with doses of 85 Gy, the pelvic failure rate is about 30%; and in Stage IIB-III tumors, doses of 85 Gy result in 35-50% pelvic failures. Refinements in brachytherapy techniques and/or use of agents to selectively sensitize the tumors to irradiation will be necessary to improve the present results in invasive carcinoma of t