Stereotactic body radiotherapy for organ-confined prostate cancer

<p>Abstract</p> <p>Background</p> <p>Improved understanding of prostate cancer radiobiology combined with advances in delivery of radiation to the moving prostate offer the potential to reduce treatment-related morbidity and maintain quality of life (QOL) following prostate cancer treatment. We present preliminary results following stereotactic body radiotherapy (SBRT) treatment for organ-confined prostate cancer.</p> <p>Methods</p> <p>SBRT was performed on 304 patients with clinically localized prostate cancer: 50 received 5 fractions of 7 Gy (total dose 35 Gy) and 254 received 5 fractions of 7.25 Gy (total dose 36.25 Gy). Acute and late toxicity was assessed using the Radiation Therapy Oncology Group scale. The Expanded Prostate Cancer Index Composite questionnaire was used to assess QOL. Prostate-specific antigen response was monitored.</p> <p>Results</p> <p>At a median 30-month (26 - 37 month, range) follow-up there were no biochemical failures for the 35-Gy dose level. Acute Grade II urinary and rectal toxicities occurred in 4% of patients with no higher Grade acute toxicities. One Grade II late urinary toxicity occurred with no other Grade II or higher late toxicities. At a median 17-month (8 - 27 month, range) follow-up the 36.25 Gy dose level had 2 low- and 2 high-risk patients fail biochemically (biopsy showed 2 low- and 1 high-risk patients were disease-free in the gland). Acute Grade II urinary and rectal toxicities occurred in 4.7% (12/253) and 3.6% (9/253) of patients, respectively. For those patients with a minimum of 12 months follow-up, 5.8% (12/206) had late Grade II urinary toxicity and 2.9% (6/206) had late Grade II rectal toxicities. One late Grade III urinary toxicity occurred; no Grade IV toxicities occurred. For both dose levels at 17 months, bowel and urinary QOL returned to baseline values; sexual QOL decreased by 10%.</p> <p>Conclusions</p> <p>The low toxicity and maintained QOL are highly encouraging. Additional follow-up is needed to determine long-term biochemical control and maintenance of low toxicity and QOL.</p

High-dose-rate brachytherapy as monotherapy for prostate cancer

Purpose: To review and analyze the published data on high-dose-rate brachytherapy as monotherapy in the treatment of prostate cancer. Methods: A literature search and a systematic review of the high-dose-rate (HDR) brachytherapy (monotherapy) prostate literature were performed on PubMed using "high-dose-rate, brachytherapy, prostate, monotherapy" as search terms. More than 80 articles and abstracts published between 1990 and 2013 were identified. Data tables were generated and summary descriptions created. Commentary and opinion was formulated through discussion and consensus based on the critical review of the literature and the author's combined personal experience and knowledge. Results: Thirteen articles reported clinical outcome and toxicity with followup ranging from 1.5 to 8.0years. Results were available for all risk groups. A variety of dose and fractionation schedules were described. Prostate-specific antigen progression-free survival ranged from 79% to 100% and local control from 97% to 100%. The toxicity rates were low. Genitourinary toxicity, mainly frequency/urgency, was 0-16% (Grade 3). Gastrointestinal toxicity was 0-2% (Grade 3). Erectile function preservation was 67-89%. The radiobiological, clinical, and technical features of HDR brachytherapy were reviewed and discussed. Conclusions: Consistently high local tumor control and low complications rates are reported with HDR monotherapy. It provides reproducible high-quality dosimetry, it has an advantage from a radiobiology perspective, and it has a good radiation safety profile. HDR brachytherapy is a safe and effective local treatment modality for prostate cancer

High-dose-rate brachytherapy as monotherapy for prostate cancer

Purpose: To review and analyze the published data on high-dose-rate brachytherapy as monotherapy in the treatment of prostate cancer. Methods: A literature search and a systematic review of the high-dose-rate (HDR) brachytherapy (monotherapy) prostate literature were performed on PubMed using "high-dose-rate, brachytherapy, prostate, monotherapy" as search terms. More than 80 articles and abstracts published between 1990 and 2013 were identified. Data tables were generated and summary descriptions created. Commentary and opinion was formulated through discussion and consensus based on the critical review of the literature and the author's combined personal experience and knowledge. Results: Thirteen articles reported clinical outcome and toxicity with followup ranging from 1.5 to 8.0years. Results were available for all risk groups. A variety of dose and fractionation schedules were described. Prostate-specific antigen progression-free survival ranged from 79% to 100% and local control from 97% to 100%. The toxicity rates were low. Genitourinary toxicity, mainly frequency/urgency, was 0-16% (Grade 3). Gastrointestinal toxicity was 0-2% (Grade 3). Erectile function preservation was 67-89%. The radiobiological, clinical, and technical features of HDR brachytherapy were reviewed and discussed. Conclusions: Consistently high local tumor control and low complications rates are reported with HDR monotherapy. It provides reproducible high-quality dosimetry, it has an advantage from a radiobiology perspective, and it has a good radiation safety profile. HDR brachytherapy is a safe and effective local treatment modality for prostate cancer

A sector-based dosimetric analysis of dose heterogeneity in high-dose-rate prostate brachytherapy

Purpose: High-dose-rate (HDR) prostate brachytherapy delivers a heterogeneous dose distribution throughout the prostate gland. There is however limited information regarding the spatial distribution of this dose heterogeneity. To this end, we analyzed the magnitude and location of intraprostatic dose heterogeneity in HDR prostate brachytherapy. Methods and Materials: Five consecutive prostate cancer patients treated with HDR were analyzed. Based on CT-simulation images, each prostate was divided into three sections (apex, base, and mid-gland). These were further subdivided into eight symmetrical sections to give a total of 24 sections. Dose-volume histograms were analyzed from V100-V200% for these 24 sections comparing the means of individual regions, left vs right, apex vs base vs mid-gland, lateral vs medial, and anterior vs posterior. A separate analysis on dose as a function of individual region volume was also performed. Results: Analyses comparing the 24 regions showed a maximum 62% difference (range, 21.9-83.9%) at V130% and 19.9% (1.9-20.8%) at V200%. Seven regions were significantly decreased and one significantly elevated from V130-V180% when compared with the mean. The means for lateral sections were 1.57-fold higher than medial sections from V110-V200% (. p &lt; 0.0001). The dose at the base was significantly higher than the rest of the gland from V120-V200 (V150, 35.6±16.2% vs 20.9±13.1%, p &lt; 0.0001). Conclusions: There is significant intra-prostatic dose heterogeneity in prostate HDR brachytherapy. This is most notable in the increased dose to base and lateral portions of the gland. Further studies are needed to determine the impact of heterogeneity on clinical outcomes

From whole gland to hemigland to ultra-focal high-dose-rate prostate brachytherapy: A dosimetric analysis

Purpose: To assess the magnitude of dosimetric reductions of a focal and ultra-focal high-dose-rate (HDR) prostate brachytherapy treatment strategy relative to standard whole gland (WG) treatment. Methods and Materials: HDR brachytherapy plans for five patients treated with WG HDR monotherapy were optimized to assess different treatment strategies. Plans were generated to treat the hemigland (HG), one-third gland (1/3G), and one-sixth gland (1/6G), as well as to assess treating the WG with a boost to one of those sub-volumes (WG+HG, WG+1/3G, WG+1/6G). Dosimetric parameters analyzed included Target D90%, V100%, V150%, Bladder (B), Rectal (R), Urethral (U) D0.1, 1 and 2cc, Urethral V75%, and the V50% to the contralateral HG. Two-tailed t tests were used for comparison of means, and p-values less than 0.05 were considered statistically significant. Results: Target objectives (D90&gt;100% and V100&gt;97%) were met in all cases. Significant organs at risk dose reductions were achieved for all approaches compared with WG plans. 1/6G vs WG plans resulted in the greatest reduction in dose with a mean bladder D2cc 24.7 vs 64.8%, rectal D2cc 32.8 vs 65.3%, urethral D1cc 52.1 vs 103.8%, and V75 14.5 vs 75% (p &lt; 0.05 for all comparisons). Conclusion: Significant dose reductions to organs at risk can be achieved using HDR focal brachytherapy. The magnitude of the reductions achievable with treating progressively smaller sub-volumes suggests the potential to reduce morbidity, but the clinical impact on morbidity and tumor control remain to be investigated