International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2002
Erectile function after permanent prostate brachytherapy.
To determine the incidence of potency preservation after permanent prostate brachytherapy using a validated patient-administered questionnaire and to evaluate the effect of multiple clinical and treatment parameters on penile erectile function. ⋯ Our results suggest that brachytherapy-induced ED is more common than previously reported and may be the result of obtaining patient information by means of a validated quality-of-life instrument by mail and not by personal interview. In multivariate analysis, only pretreatment potency, supplemental EBRT, and diabetes maintained statistical significance. Most patients with brachytherapy-induced ED responded favorably to sildenafil. Although the 6-year actuarial incidence of potency preservation was 39%, 52% of patients not receiving supplemental EBRT maintained potency. In addition, with pharmacologic support, 92% of patients maintained potency.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2002
Impact of biochemical failure on overall survival after radiation therapy for localized prostate cancer in the PSA era.
To study the impact of biochemical failure on overall survival rates during the first 10 years after definitive radiotherapy for localized prostate cancer. ⋯ Biochemical failure after definitive radiotherapy for localized prostate cancer is not associated with increased mortality within the first 10 years after initial therapy, although a trend toward worse outcome was observed at 10 years. Longer follow-up from initial therapy is needed to fully understand the impact of biochemical failure on overall survival. With longer follow-up, significant differences might be observed at 15 or 20 years after therapy.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2002
Relationship between percent positive biopsies and biochemical outcome after permanent interstitial brachytherapy for clinically organ-confined carcinoma of the prostate gland.
Recently, the percentage of positive prostate biopsies has been reported to be statistically significant in predicting the biochemical outcome after either radical prostatectomy or 3-dimensional conformal external beam radiotherapy. In this study, we evaluated the impact of the percentage of positive prostate biopsies in predicting the 5-year biochemical outcome for patients with clinically organ-confined prostate cancer undergoing permanent interstitial brachytherapy. ⋯ Although a significant trend was found for biochemical failure with increasing percent positive biopsies in the overall population, our results suggest that the percentage of positive biopsies is not statistically significant in predicting the 5-year biochemical disease-free outcome for patients with low, intermediate, and high-risk disease undergoing permanent prostate brachytherapy. Only the Gleason score in intermediate-risk patients and the pretreatment PSA level in high-risk patients was predictive of biochemical failure. We believe this relative lack of significance for the percentage of positive biopsies is a result of dose escalation far exceeding other radiotherapy modalities and the ability to aggressively treat the periprostatic region compared with radical prostatectomy by way of the accurate placement of periprostatic seeds.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2002
The optimal fraction size in high-dose-rate brachytherapy: dependency on tissue repair kinetics and low-dose rate.
Indications of the existence of long repair half-times on the order of 2-4 h for late-responding human normal tissues have been obtained from continuous hyperfractionated accelerated radiotherapy (CHART). Recently, these data were used to explain, on the basis of the biologically effective dose (BED), the potential superiority of fractionated high-dose rate (HDR) with large fraction sizes of 5-7 Gy over continuous low-dose rate (LDR) irradiation at 0.5 Gy/h in cervical carcinoma. We investigated the optimal fraction size in HDR brachytherapy and its dependency on treatment choices (overall treatment time, number of HDR fractions, and time interval between fractions) and treatment conditions (reference low-dose rate, tissue repair characteristics). ⋯ Radiobiologic model calculations presented here aim to demonstrate that hypofractionation in HDR might have its opportunities for widening the therapeutic window, but definitely has its limits. For each specific combination of the parameters, a theoretical optimal HDR fraction size with regard to relative or absolute normal tissue sparing can be estimated, but because of uncertainty in the biologic parameters, these hypofractionation schemes cannot be generalized for all HDR brachytherapy indications.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2002
Positive resection margin and/or pathologic T3 adenocarcinoma of prostate with undetectable postoperative prostate-specific antigen after radical prostatectomy: to irradiate or not?
To evaluate the efficacy of postoperative adjuvant radiotherapy (RT) for positive resection margin and/or pathologic T3 (pT3) adenocarcinoma of the prostate with undetectable postoperative prostate-specific antigen (PSA) levels. ⋯ Postoperative adjuvant RT was associated with a lower risk of relapse, including freedom from PSA failure, compared with observation alone for pT3 and/or margin-positive disease with undetectable postoperative PSA levels. This was accomplished with a minimal risk of serious RT morbidity.