International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2000
Comparative StudyNormal tissue dosimetric comparison between HDR prostate implant boost and conformal external beam radiotherapy boost: potential for dose escalation.
To compare the dose and volume of bladder and rectum treated using high-dose-rate (HDR) prostate implant boost versus conformal external beam radiotherapy boost, and to use the dose-volume information to perform a critical volume tolerance (CVT) analysis and then estimate the potential for further dose escalation using HDR brachytherapy boost. ⋯ HDR brachytherapy can provide better sparing of rectum and bladder while delivering a higher dose to the prostate. Even with the increased late effects of high dose per fraction, there is still a potential for dose escalation beyond external radiotherapy limits using HDR brachytherapy.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2000
Stage III thymoma: pattern of failure after surgery and postoperative radiotherapy and its implication for future study.
With the conventional approach of surgery and postoperative radiotherapy for patients with Masaoka Stage III thymoma, progress has been slow for an improvement in the long-term survival rate over the past 20 years. The objective of this study was to evaluate the pattern of failure and survival after surgery and postoperative radiotherapy in Stage III thymoma and search for a new direction for better therapy outcome. ⋯ Incomplete resection leads to poor results even with postoperative radiotherapy or chemoradiotherapy in Stage III thymoma. Pleural recurrence is also observed more often among patients treated with surgery first. These findings suggest that preoperative radiotherapy or chemoradiotherapy may result in an increase in survival by improving the rate of complete resection and reducing local and pleural recurrences.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2000
Preoperative chemoradiation in fixed distal rectal cancer: dose time factors for pathological complete response.
Preoperative chemoradiation is being utilized extensively in the treatment of rectal cancer. However, a variety of dose time factors in both delivery of chemotherapy and irradiation remain to be established. This study was undertaken to examine the impact of dose time factors on pathological complete response (pCR) rates following preoperative chemoradiation for fixed rectal cancer. ⋯ Dose intensity of 5-FU and dose of radiation correlate significantly with the likelihood of achieving a pCR. Continuous infusion 5-FU (CI) and a preoperative radiation dose of 5500 cGy or higher can achieve pCR rates of approximately 50%, even in fixed cancers of the rectum.
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Int. J. Radiat. Oncol. Biol. Phys. · Feb 2000
Higher than standard radiation doses (> or =72 Gy) with or without androgen deprivation in the treatment of localized prostate cancer.
To study the effect on biochemical relapse-free survival (bRFS) and clinical disease-free survival of radiation doses delivered to the prostate and periprostatic tissues for localized prostate cancer. ⋯ Patients receiving radiation doses exceeding 72 Gy had significantly better bRFS and clinical disease-free survival rates. Although results need to be confirmed with longer follow-up, these preliminary results are extremely encouraging. If these results are confirmed by other institutions and by longer follow-up, RT doses exceeding 72 Gy should be considered as standard of care.
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Int. J. Radiat. Oncol. Biol. Phys. · Feb 2000
Comparative StudyScrutiny of the ASTRO consensus definition of biochemical failure in irradiated prostate cancer patients demonstrates its usefulness and robustness. American Society for Therapeutic Radiology and Oncology.
The goals of this study are: (1) to establish the robustness of the Fox Chase Cancer Center (FCCC) and the American Society for Therapeutic Radiology and Oncology (ASTRO) consensus definitions of failure by comparing biochemical estimates under various modifications of the censoring and failure time components to their respective unaltered definitions; (2) to isolate the source of variation between the two definitions of failure; and (3) to describe the hazard of failure over time for each definition. ⋯ Both FCCC and ASTRO failure definitions were robust to modifications in censoring and the inclusion of patients with long doubling times. The ASTRO failure definition was robust to specifying the time to failure at first rise, as opposed to midway between nadir and first rise. Similarities in estimates for all patients versus patients with agreeing failure status suggest that differences in failure definition lie in the specification of time to failure. The ASTRO definition of failure is more appropriate because it does not impose an empirical failure marker but is based on the initiation of biochemical rise. The use of the ASTRO consensus definition demonstrated little risk of biochemical failure 4 years beyond treatment. The ASTRO failure definition should be adopted in all research involving biochemical failure analysis of men treated with radiation therapy.