International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 1998
Clinical TrialDose escalation with three-dimensional conformal radiation therapy affects the outcome in prostate cancer.
Three-dimensional conformal radiation therapy (3D-CRT) is a technique designed to deliver prescribed radiation doses to localized tumors with high precision, while effectively excluding the surrounding normal tissues. It facilitates tumor dose escalation which should overcome the relative resistance of tumor clonogens to conventional radiation dose levels. The present study was undertaken to test this hypothesis in patients with clinically localized prostate cancer. ⋯ The data provide evidence for a significant effect of dose escalation on the response of human prostate cancer to irradiation and defines new standards for curative radiotherapy in this disease.
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 1998
Dose escalation with 3D conformal treatment: five year outcomes, treatment optimization, and future directions.
To report the 5-year outcomes of dose escalation with 3D conformal treatment (3DCRT) of prostate cancer. ⋯ A dose response was observed for patients with pretreatment PSA >10 ng/ml based on 5-year bNED results. No dose response was observed for patients with pretreatment PSA < 10 ng/ml. Dose response was observed for FC-LENT grade 2 and grade 3,4 GI sequelae and for LENT grade 2 GU sequelae. Optimization of treatment was made possible by the results in this report. The improvement in 5-year bNED rates for patients with PSA levels > 10 ng/ml strongly suggests that clinical trials employing radiation should investigate the use of 3DCRT and prostate doses of 76-80 Gy.
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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.