International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Dec 2003
Patterns of breast recurrence in a pilot study of brachytherapy confined to the lumpectomy site for early breast cancer with six years' minimum follow-up.
In this pilot study of high-dose-rate brachytherapy to the lumpectomy site as the sole radiation, ipsilateral and contralateral breast recurrences are documented with specific attention to the location of recurrence relative to the lumpectomy site. ⋯ In this pilot study, breast recurrences outside of the lumpectomy site were the predominant pattern of recurrence.
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Int. J. Radiat. Oncol. Biol. Phys. · Dec 2003
Hypofractionated conformal radiotherapy in carcinoma of the prostate: five-year outcome analysis.
Recent publications have indicated that the alpha/beta ratios for carcinoma of the prostate are much lower than had originally been thought, suggesting that prostate cancer may be highly sensitive to fraction size. We have reviewed our unique experience of the use of 3.13 Gy fractions in a large cohort of men treated homogeneously in a single institute. ⋯ These data indicate that the delivery of a relatively low total dose using a hypofractionated regime results in similar tumor control and normal-tissue toxicity to 65-70 Gy delivered in 1.8-2 Gy fractions. These data suggest that this is an acceptable regime for good-prognosis patients. However, because of the evidence for a dose effect at doses above 70 Gy with "conventional fractionation," we are now treating intermediate- and poor-risk patients within a hypofractionated dose escalation trial to 60 Gy in 20 fractions using intensity- modulated radiotherapy.
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Int. J. Radiat. Oncol. Biol. Phys. · Dec 2003
Reproducibility of lung tumor position and reduction of lung mass within the planning target volume using active breathing control (ABC).
The active breathing control (ABC) device allows for temporary immobilization of respiratory motion by implementing a breath hold at a predefined relative lung volume and air flow direction. The purpose of this study was to quantitatively evaluate the ability of the ABC device to immobilize peripheral lung tumors at a reproducible position, increase total lung volume, and thereby reduce lung mass within the planning target volume (PTV). ⋯ Results from this study indicate that there remains some inter-breath hold variability in peripheral lung tumor position with the use of ABC inspiration breath hold, which prevents significant PTV margin reduction. However, lung volumes can significantly increase, thereby decreasing the mass of lung within a standard PTV.
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Recently, low alpha/beta values of 1.2 and 1.5 Gy for prostate tumors have been derived from clinical results of external beam radiotherapy and of permanent implants of (125)I and (103)Pd. In the analyses the contributions of tumor repopulation, and edema as a result of inserting radioactive seeds in the prostate, have been ignored. In this paper we reanalyzed the clinical data and introduced the contribution of repopulation and edema. ⋯ It seems now that the alpha/beta value is low, 3.1-3.9 Gy, but not as low as the 1.2 and 1.5 Gy reported earlier.
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2003
Multicenter Study Comparative StudyComparison of alternative biochemical failure definitions based on clinical outcome in 4839 prostate cancer patients treated by external beam radiotherapy between 1986 and 1995.
To assess the merit of the American Society for Therapeutic Radiology and Oncology (ASTRO) definition of biochemical failure after external beam radiotherapy for prostate cancer by testing alternative prostate-specific antigen (PSA) failure definitions against the "gold standard" of clinical failure and to study the effect of backdating the time of failure. ⋯ The ASTRO failure definition ended the confusion resulting from different failure definitions that had been in use, and it did so accurately enough that it is probably not necessary to recalculate previously published results. Nevertheless, for the current pooled analysis of outcome in 4839 men with a 6.3-year median follow-up, other definitions of biochemical failure were superior as assessed by various quantitative measures of concordance of biochemical and ultimate clinical failure. An additional disadvantage of the ASTRO definition is the bias introduced by backdating failures, as well as the necessarily retrospective nature of its application. Some "current" definitions, but not those based on the PSA level rising above a fixed threshold, have significantly higher sensitivity and specificity, do not lead to biased estimations of biochemical disease-free survival, and are directly applicable during patient counseling. These are all issues that would play a role in replacing the ASTRO consensus definition.