Publications (80) View all
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Article: A comparative dosimetric analysis of virtual stereotactic body radiotherapy to high-dose-rate monotherapy for intermediate-risk prostate cancer.
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ABSTRACT: PURPOSE: Stereotactic body radiotherapy (SBRT) is being used with increasing frequency as definitive treatment of early stage prostate cancer. Much of the justification for its adoption was derived from earlier clinical results using high-dose-rate (HDR) brachytherapy. We determine whether HDR's dosimetry can be achieved by virtual SBRT. METHODS AND MATERIALS: Patients with intermediate-risk prostate cancer on a prospective trial evaluating the efficacy of HDR monotherapy treated to dose of 9.5Gy×4 fractions were used for this study. A total of 5 patients were used in this analysis. Virtual SBRT plans were developed to reproduce the planning target volume (PTV) HDR dose distributions. Both normal tissue- and PTV-prioritized plans were generated. RESULTS: From the normal tissue-prioritized plan, HDR and virtual SBRT achieved similar PTV V100 (93.8% vs. 93.1%, p=0.20) and V150 (40.3% vs. 42.9%, p=0.69) coverage. However, the PTV V200 was not attainable with SBRT (15.2% vs. 0.0%, p<0.001). The rectal Dmax was significantly lower with HDR (94.2% vs. 99.42%, p=0.05). The rectal D2 cc was also lower (60.8% vs. 71.1%, p=0.07). Difference in D1 cc urethral dose was not significantly different (87.7% vs. 75.2%, p=0.33). Comparing the PTV-prioritized plans, the rectal Dmax (94.2% vs. 111.1%, p=0.05) and mean dose (27.1% vs. 33.3%, p=0.03) were significantly higher using SBRT, and the rectal D2 cc was higher using SBRT (60.8% vs. 81.8%, p=0.07). CONCLUSIONS: HDR achieves significantly higher intraprostatic doses while achieving a lower maximum rectal dose compared with our virtual SBRT treatment planning. Future studies should compare clinical outcomes and toxicity between these modalities.Brachytherapy 04/2013; · 1.47 Impact Factor -
Article: Favourable long-term outcomes with brachytherapy-based regimens in men ≤60 years with clinically localized prostate cancer.
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ABSTRACT: WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Brachytherapy (BT)-based treatment for clinically localized prostate cancer is a well-accepted treatment strategy; however, there is concern that long-term outcomes and morbidity may not be acceptable in young patients (≤60 years). We report our long-term experience with BT in men aged ≤ 60 years with a minimum of 2 years of post-treatment follow-up. Our results show low treatment-related morbidity and excellent long-term outcomes with BT-based treatment and suggest that such treatment should be offered to this patient population. OBJECTIVE: To report long-term outcomes of men ≤60 years treated with brachytherapy (BT) for low- and intermediate-risk prostate cancer. PATIENTS AND METHODS: Of 1655 patients treated with BT for clinically localized prostate cancer between January 1998 and May 2008 at Memorial Sloan-Kettering Cancer Center, 236 patients with National Comprehensive Cancer Network low- (n = 178) or intermediate-risk (n = 58) prostate cancer were ≤60 years old with a 3-year minimum follow-up, and represent the subjects of this report. Brachytherapy was given either as monotherapy (n = 169) or with external beam radiation therapy (EBRT; n = 67). Forty-four patients (19%) received neoadjuvant cytoreductive hormone therapy. The 'nadir+2' definition was used for prostate-specific antigen (PSA) recurrence. Common Terminology Criteria for Acute Events (CTCAE) v 3.0 was used to grade genitourinary (GU) and gastrointestinal (GI) toxicity. Potency was defined as the ability to obtain an erection suitable for intercourse or an International Index of Erectile Function score ≥ 22. The Kaplan-Meier method and Cox regression were used for statistical analysis. The median follow-up was 83 months. RESULTS: The 8-year PSA relapse-free survival (RFS), cancer-specific and overall survival rates for the entire cohort were 96, 99 and 96%, respectively. For patients with low-risk disease, the 8-year PSA RFS rate was 97% and for intermediate-risk patients it was 94% (P = 0.34). There was no difference in PSA RFS between BT alone and combined therapy (P = 0.17). Late grade ≥ 2 GU and GI toxicity was 14 and 3%, respectively. Of 150 patients potent before treatment, 76 (51%) were potent at last follow-up, with 50/76 (66%) using no medication. There was no significant difference in post-treatment potency between BT alone and BT with EBRT (P = 0.74). CONCLUSIONS: Brachytherapy provides patients aged ≤ 60 years with low- and intermediate-risk prostate cancer with excellent outcomes and has a low risk of significant long-term GU or GI morbidity. Erectile function is preserved in >50% of patients and the majority do not require erectile dysfunction medication.BJU International 04/2013; · 2.84 Impact Factor -
Article: A New Risk Classification System for Therapeutic Decision Making with Intermediate-risk Prostate Cancer Patients Undergoing Dose-escalated External-beam Radiation Therapy.
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ABSTRACT: BACKGROUND: The management of intermediate-risk prostate cancer (PCa) is controversial, in part due to the heterogeneous nature of patients falling within this classification. OBJECTIVE: We propose a new risk stratification system for intermediate-risk PCa to aid in prognosis and therapeutic decision making. DESIGN, SETTING, AND PARTICIPANTS: Between 1992 and 2007, 1024 patients with National Comprehensive Cancer Network intermediate-risk PCa and complete biopsy information were treated with definitive external-beam radiation therapy (EBRT) utilizing doses ≥81Gy. Unfavorable intermediate-risk (UIR) PCa was defined as any intermediate-risk patient with a primary Gleason pattern of 4, percentage of positive biopsy cores (PPBC) ≥50%, or multiple intermediate-risk factors (IRFs; cT2b-c, prostate-specific antigen [PSA] 10-20, or Gleason score 7). INTERVENTION: All patients received EBRT with ≥81Gy with or without neoadjuvant and concurrent androgen-deprivation therapy (ADT). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Univariate and multivariate analyses were performed using a Cox proportional hazards model for PSA recurrence-free survival (PSA-RFS) and distant metastasis (DM). PCa-specific mortality (PCSM) was analyzed using a competing-risk method. RESULTS AND LIMITATIONS: Median follow-up was 71 mo. Primary Gleason pattern 4 (hazard ratio [HR]: 3.26; p<0.0001), PPBC ≥50% (HR: 2.72; p=0.0007), and multiple IRFs (HR: 2.20; p=0.008) all were significant predictors of increased DM in multivariate analyses. Primary Gleason pattern 4 (HR: 5.23; p<0.0001) and PPBC ≥50% (HR: 4.08; p=0.002) but not multiple IRFs (HR: 1.74; p=0.21) independently predicted for increased PCSM. Patients with UIR disease had inferior PSA-RFS (HR: 2.37; p<0.0001), DM (HR: 4.34; p=0.0003), and PCSM (HR: 7.39; p=0.007) compared with those with favorable intermediate-risk disease, despite being more likely to receive neoadjuvant ADT. Short follow-up and retrospective study design are the primary limitations. CONCLUSIONS: Intermediate-risk PCa is a heterogeneous collection of diseases that can be separated into favorable and unfavorable subsets. These groups likely will benefit from divergent therapeutic paradigms.European urology 03/2013; · 7.67 Impact Factor -
Article: Image-guided Radiation Therapy for Liver Tumors: Gastrointestinal Histology Matters.
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ABSTRACT: OBJECTIVES:: To describe the safety and efficacy of single-fraction and hypofractionated image-guided radiotherapy techniques for the treatment of large liver tumors. METHODS:: Forty-six patients, with 50 tumors (10 primary liver tumors, 40 liver metastases) from March 2004 to March 2011 were reviewed. The maximal tumor diameter ranged from 1.2 to 11.3 cm (median, 4.2 cm). Eighty-seven percent of patients received prior systemic chemotherapy. Fifty-nine percent had prior invasive local therapy including surgery, ablation, or embolization. Twenty-five lesions were treated with hypofractionated therapy (24 to 30 Gy in 3 to 5 fractions), whereas 19 received a single fraction (18 or 24 Gy). Local control (LC) was calculated using competing risk analysis. Overall survival was calculated by the Kaplan-Meier method. RESULTS:: Median follow-up for all patients was 29.8 months (range, 3 to 46 mo). The median survival was 15.4 months. The 1- and 2-year LC rates were 78% and 75%, respectively. Dose and tumor size had no significant effect on tumor progression. The local progression at 1 and 2 years was 29% and 32% for gastrointestinal (GI) histologies versus 0% for non-GI histologies (P=0.02). Tumor volumes larger than 112 cm correlated with decreased survival (P=0.05). Three patients developed late grade 3 GI stricture or ulceration. CONCLUSIONS:: Image-guided radiotherapy for liver tumors achieves good rates of LC with minimal toxicity at 1 and 2 years even in patients with large or recurrent disease that has been heavily pretreated. GI histology demonstrated decreased LC rates. Further management strategies should be considered in these patients.American journal of clinical oncology 03/2013; · 2.21 Impact Factor -
Article: Intraoperative and percutaneous iridium-192 high-dose-rate brachytherapy for previously irradiated lesions of the spine.
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ABSTRACT: PURPOSE: Advances in stereotactic radiosurgery have improved local control of spine metastases, but local failure is still a problem and repeat irradiation is limited by normal tissue tolerance. A novel high-dose-rate (HDR) brachytherapy technique has been developed to treat these previously irradiated lesions. METHODS AND MATERIALS: Five patients with progressive disease at previously irradiated sites in the spine who were not amenable to further external beam radiation were treated. Catheters were placed intraoperatively in 2 patients and percutaneously implanted in 3 patients with image-guided techniques. Conformal plans were generated to deliver dose to target tissues and spare critical structures. Patients received single-fraction treatment using HDR iridium-192 brachytherapy. RESULTS: Median dose was 14 Gy (range, 12-18 Gy) with a median gross total volume D90 of 75% (range, 31-94%); spinal cord/cauda equina dose constraints were met. At a median followup of 9 months, no local progression of disease has been observed. Four patients had reduction in pain 1-4 weeks after treatment. No brachytherapy-related complications have been observed. CONCLUSIONS: Intraoperative and percutaneous iridium-192 HDR spine brachytherapy techniques were not associated with complications or acute toxicity. There has been no local progression at treated sites, and most patients experienced reduction in cancer-related pain.Brachytherapy 02/2013; · 1.47 Impact Factor
