Population-based 10-year oncologic outcomes after low-dose-rate brachytherapy for low-risk and intermediate-risk prostate cancer
ABSTRACT BACKGROUND.: The objective of this study was to report the rates of disease-free survival (DFS), cause-specific survival (CSS), and overall survival after low-dose-rate (LDR) prostate brachytherapy (PB). METHODS.: Data from 1006 consecutive patients with prostate cancer who received LDR-PB and underwent implantation on or before October 23, 2003 were extracted from a prospective database on November 11, 2011. The selected patients had low-risk (58%) or intermediate-risk (42%) disease according to National Comprehensive Cancer Network criteria. The Phoenix threshold was used to define biochemical relapse. Sixty-five percent of patients received 3 months of neoadjuvant androgen-deprivation therapy (ADT) and 3 months of concomitant ADT. Univariate and multivariate analyses are reported in relation to patient, tumor, and treatment variables. RESULTS.: The median follow-up was 7.5 years. By using Fine and Gray competing risks analysis, the 5-year and 10-year actuarial DFS rates were 96.7% (95% confidence interval, 95.2%-97.7%) and 94.1% (95% confidence interval, 92%-95.6%), respectively. When applied to the whole cohort, none of the usual prognostic variables, including dose metrics, were correlated with DFS. However, in both univariate and multivariate models, increasing dose was the only covariate that correlated with improved DFS for the subset of men (N = 348) who did not receive ADT (P = .043). The actuarial 10-year CSS rate was 99.1% (95% confidence interval, 97.3%-99.7%). The overall survival rate was 93.8% at 5 years (95% confidence interval, 92%-95.1%) and 83.5% at 10 years (95% confidence interval, 79.8%-86.6%). Only age at implantation (P = .0001) was correlated with overall survival in multivariate analysis. CONCLUSIONS.: In a consecutive cohort of 1006 men with National Comprehensive Cancer Network low-risk and intermediate-risk prostate cancer, the actuarial rate of recurrent disease after LDR-PB was approximately 3% at 5 years and 6% at 10 years. Cancer 2012. © 2012 American Cancer Society.
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ABSTRACT: Prostate brachytherapy can be used as a monotherapy for low- and intermediate-risk patients or in combination with external beam radiation therapy (EBRT) as a form of dose escalation for selected intermediate- and high-risk patients. Prostate brachytherapy with either permanent implants (low dose rate [LDR]) or temporary implants (high dose rate [HDR]) is emerging as the most effective radiation treatment for prostate cancer. Several large Canadian brachytherapy programs were established in the mid- to late-1990s. Prostate brachytherapy is offered in British Columbia, Alberta, Manitoba, Ontario, Quebec and New Brunswick. We anticipate the need for brachytherapy services in Canada will significantly increase in the near future. In this review, we summarize brachytherapy programs across Canada, contemporary eligibility criteria for the procedure, toxicity and prostate-specific antigen recurrence free survival (PRFS), as published from Canadian institutions for both LDR and HDR brachytherapy.Canadian Urological Association journal = Journal de l'Association des urologues du Canada 02/2013; 7(1-2):51-8. DOI:10.5489/cuaj.218 · 1.92 Impact Factor
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ABSTRACT: PURPOSE: To explore whether DNA ploidy of prostate cancer cells determined from archived transrectal ultrasound-guided biopsy specimens correlates with disease-free survival. METHODS AND MATERIALS: Forty-seven failures and 47 controls were selected from 1006 consecutive low- and intermediate-risk patients treated with prostate (125)I brachytherapy (July 1998-October 2003). Median follow-up was 7.5 years. Ten-year actuarial disease-free survival was 94.1%. Controls were matched using age, initial prostate-specific antigen level, clinical stage, Gleason score, use of hormone therapy, and follow-up (all P nonsignificant). Seventy-eight specimens were successfully processed; 27 control and 20 failure specimens contained more than 100 tumor cells were used for the final analysis. The Feulgen-Thionin stained cytology samples from archived paraffin blocks were used to determine the DNA ploidy of each tumor by measuring integrated optical densities. RESULTS: The samples were divided into diploid and aneuploid tumors. Aneuploid tumors were found in 16 of 20 of the failures (80%) and 8 of 27 controls (30%). Diploid DNA patients had a significantly lower rate of disease recurrence (P=.0086) (hazard ratio [HR] 0.256). On multivariable analysis, patients with aneuploid tumors had a higher prostate-specific antigen failure rate (HR 5.13). Additionally, those with "excellent" dosimetry (V100 >90%; D90 >144 Gy) had a significantly lower recurrence rate (HR 0.25). All patients with aneuploid tumors and dosimetry classified as "nonexcellent" (V100 <90%; D90 <144 Gy) (5 of 5) had disease recurrence, compared with 40% of patients with aneuploid tumors and "excellent" dosimetry (8 of 15). In contrast, dosimetry did not affect the outcome for diploid patients. CONCLUSIONS: Using core biopsy material from archived paraffin blocks, DNA ploidy correctly classified the majority of failures and nonfailures in this study. The results suggest that DNA ploidy can be used as a useful marker for aggressiveness of localized prostate cancer. A larger study will be necessary to further confirm our hypothesis.International journal of radiation oncology, biology, physics 05/2013; 86(5). DOI:10.1016/j.ijrobp.2013.04.011 · 4.18 Impact Factor
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ABSTRACT: Brachytherapy delivers the most conformal high dose radiotherapy possible to the prostate, using either a low dose rate (LDR) or high dose rate (HDR) technique. It may be used either alone as monotherapy or in combination with external beam radiotherapy (EBRT) as a local boost. Comparative efficacy studies, including one randomised controlled trial, consistently show higher cancer control rates when brachytherapy is used compared with EBRT alone, with even some evidence of improvement in survival. There are now extensive mature data supporting the use of LDR as monotherapy for patients with low-risk and selected intermediate-risk disease, with most series reporting long-term disease control rates of over 90% after high-quality implants. HDR is most commonly combined with EBRT to treat intermediate- and high-risk disease, with disease control rates of over 90% reported. The low alpha/beta ratio of prostate cancer combined and the ability to optimally sculpt dose distribution provides the biological and dosimetric rationale for HDR. HDR enables more consistent implant quality than LDR, with evidence of lower acute and late toxicity. Many dose and fractionation schedules of HDR in combination with EBRT have been investigated, but a single fraction of 10-15 Gy is commonly combined with EBRT to a dose of 40-50 Gy to treat intermediate- and high-risk disease. High disease control rates are also reported with HDR as monotherapy, particularly in patients with low- and intermediate-risk disease. Although older series have delivered four to six fractions of HDR, there is growing evidence to support the delivery of HDR in three or even two fractions. Single-fraction HDR monotherapy is now being investigated and if early data are confirmed with longer follow-up, may well become the treatment of choice for many men with localised prostate cancer.Clinical Oncology 05/2013; 25(8). DOI:10.1016/j.clon.2013.04.009 · 2.83 Impact Factor