International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · May 1995
Prostate-specific antigen and radiation therapy for clinically localized prostate cancer.
This study was undertaken to: (a) define the prognostic significance of pretreatment serum prostate-specific antigen (PSA) levels in localized prostate cancer treated with radiation; (b) define the prognostic usefulness of postradiation PSA levels; (c) evaluate the outcome of radiation using PSA as an endpoint. ⋯ Pretreatment serum PSA is the single most important predictor of disease outcome after radiation for local prostate cancer. Tumor grade has a lesser though significant prognostic role. Postirradiation nadir PSA value during the first year is a sensitive indicator of response to treatment. Only nadir values < 1 ng/ml are associated with a favorable outlook. A significant fraction of men with T1/T2 disease may be cured with radiation. There was no evidence for a cured fraction among patients with T3/T4 disease.
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Int. J. Radiat. Oncol. Biol. Phys. · May 1995
Conformal treatment of prostate cancer with improved targeting: superior prostate-specific antigen response compared to standard treatment.
Conformal radiation therapy (CRT) decreases the morbidity of prostate cancer treatment, but no published data attest to the improved ability of CRT to control disease. Therefore, we compared Prostate-Specific Antigen (PSA) response at 1 year among similarly staged patients treated by conformal techniques to those treated with conventional approaches, looking for an early indicator of tumor response. ⋯ As measured by PSA normalization, conformal techniques with improved targeting produced responses that were significantly better than conventional techniques among patients treated with definitive irradiation. These results, coupled with our previously documented reduction of acute and chronic sequelae, support the continued use of CRT as a more effective method of treatment for prostate cancer.
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Int. J. Radiat. Oncol. Biol. Phys. · May 1995
Dosimetry guidelines to minimize urethral and rectal morbidity following transperineal I-125 prostate brachytherapy.
To establish dosimetry guidelines to minimize urethral and rectal morbidity following permanent I-125 prostatic brachytherapy. ⋯ Postimplant, CT-based dosimetry can predict which patients are at higher risk of radiation-related morbidity. More simplistic parameters including the MPD, total activity implanted, or mCi/source, had no relationship with morbidity. To decrease the risk of long-term morbidity, an effort should be made to keep the central urethral dose below 400 Gy, and the rectal surface dose below 100 Gy.
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Int. J. Radiat. Oncol. Biol. Phys. · May 1995
Prostate-specific antigen for pretreatment prediction and posttreatment evaluation of outcome after definitive irradiation for prostate cancer.
This study was undertaken to assess the predictive value of pretreatment prostate-specific antigen (PSA) and the difference between clinical and PSA disease-free status in patients with long-term follow-up after irradiation for prostatic carcinoma. Comparison of the distribution of prognostic factors between surgical and radiation series was also made. ⋯ With long-term follow-up, the pretreatment PSA level continues to be a powerful predictor of clinical and biochemical outcome in patients irradiated for apparently localized prostate cancer. Differences between clinical and PSA outcome can be considerable, but oftentimes clinically insignificant. The distribution of prognostic factors between radiation and prostatectomy series seems to favor the latter.
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 1995
Treatment planning structure and process in the United States: a "Patterns of Care" study.
To conduct a study of the structure and process of treatment planning in the United States. ⋯ This is the first patterns of treatment planning study carried out in the United States and the results reported here will establish a baseline for future studies. The present study has identified some elements that were unexpected, such as the percentage of facilities lacking formal QA programs for treatment planning systems; however, it has not established any impact of such findings. It is recommended that future studies include the availability of new technologies such as multileaf collimation, dynamic wedges, digital portal imaging, and CT simulation. With the increasing nationwide concern with the cost of health care, we must continue to monitor the implementation, use, and impact on treatment outcome of new and expensive technologies.