CyberKnife stereotactic radiotherapy as monotherapy for low- to intermediate-stage prostate cancer: early experience, feasibility, and tolerance.
ABSTRACT The CyberKnife (CK), a linear accelerator mounted on a robotic device, enables excellent dose conformation to the target and minimizes dose to surrounding normal tissue. It is a very suitable device for performing hypofractionated stereotactic body radiotherapy as monotherapy for low- to intermediate-risk prostate cancer patients. We report our early experience using this technique.
Between June 2008 and June 2009, 10 patients underwent CK monotherapy as treatment for their prostate cancer (stage <or=T2b, Gleason score (GS) <or=7, initial PSA <or=15 microg/L). The prescribed dose was 38 Gy in four daily fractions of 9.5 Gy. The International Prostate Symptom Score and Radiation Therapy Oncology Group symptom scale were prospectively administered before and at 0.5, 1, 2, 3, 6, and 12 months.
Median age of the patients was 71 years (range, 66-76). Three patients had stage T2a and 7a T1c disease, one patient had GS of 7, and all others had GS of 6. Median follow-up was 5.1 months. Median initial PSA was 8.3 ng/mL (range, 1.3-13.6 ng/mL). Median planning target volume delineated on computed tomography after matching with the magnetic resonance imaging scan was 107 cc (range, 42-158 cc). The median V100 of the prostate was 95.8% (range, 94.8-97.2). The D95 of the prostate was 38.3 Gy (range, 38.1-38.8 Gy). The constraints for the bladder, rectum, and urethra were well met. The International Prostate Symptom Scores after 3 months were stable compared with the pretreatment scores. Urinary and bowel Radiation Therapy Oncology Group symptoms were mild and within the expected levels.
This regimen of stereotactic CK monotherapy for low- to intermediate-risk prostate cancer with excellent dose coverage of the prostate was well tolerated. Data collection is ongoing for further assessment of toxicity and PSA response.
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ABSTRACT: The aim of the present study was to evaluate the efficacy and toxicity of stereotactic body radiation therapy (SBRT) for low- to intermediate-risk prostate adenocarcinoma. Thirty-nine patients were retrospectively reviewed. The SBRT was delivered using the CyberKnife with the fiducial tracking method combined with In-tempo imaging. The gross target volume, which included the prostate only, was delineated on the fused CT/MRI scans. The prescription dose was delivered every other day as 5 fractions of 7.5 Gy. Venous blood was obtained before and after SBRT to assess the prostate-specific antigen (PSA) level. Toxicity was evaluated using the CTCAE, v4.03. The median follow-up time was 30.0 months. The median initial PSA level was 7.7 ng/mL. PSA levels decreased in all patients treated with SBRT, and after 5 months, the median PSA was less than 2 ng/mL. The rate of overall 3-yr actuarial biochemical failure free survival was 93.9%. Acute side effects were generally comparable with those of previous studies. The PSA change and toxicity after SBRT for low- to intermediate-risk prostate adenocarcinoma indicates favorable biochemical responses and tolerable levels of toxicity. Additionally short course treatment may produce cost benefit and convenience to patients.Journal of Korean Medical Science 05/2015; 30(6):710-715. DOI:10.3346/jkms.2015.30.6.710 · 1.25 Impact Factor
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ABSTRACT: Stereotactic body radiation therapy (SBRT) is derived from the techniques of stereotactic radiosurgery used to treat lesions in the brain and spine. It combines multiple finely collimated radiation beams and stereotaxy to deliver a high dose of radiation to an extracranial target in the body in a single dose or a few fractions. This review provides a broad overview of the current state of SBRT for solid malignant tumors. Reviewers identified a total of 124 relevant studies. To our knowledge, no published comparative studies address the relative effectiveness and safety of SBRT versus other forms of external-beam radiation therapy. Stereotactic body radiation therapy seems to be widely diffused as a treatment of various types of cancer, although most studies have focused only on its use for treating thoracic tumors. Comparative studies are needed to provide evidence that the theoretical advantages of SBRT over other radiation therapies actually occur in the clinical setting; this area is currently being studied in only 1 small trial.Annals of internal medicine 06/2011; 154(11):737-45. DOI:10.1059/0003-4819-154-11-201106070-00343 · 16.10 Impact Factor
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ABSTRACT: Background There is growing evidence that prostate cancer (PC) cells are more sensitive to high fraction dose in hypofractionation schemes. High-dose-rate (HDR) brachytherapy as monotherapy is established to be a good treatment option for PC using extremely hypofractionated schemes. This hypofractionation can also be achieved with stereotactic body radiotherapy (SBRT). We report results on toxicity, PSA response, and quality of life (QOL) in patients treated with SBRT for favorable-risk PC. Methods Over the last 4 years, 50 hormone-naïve patients with low- and intermediate-risk PC were treated with SBRT to a total dose of 38 Gy delivered in four daily fractions of 9.5 Gy. An integrated boost to 11 Gy per fraction was applied to the dominant lesion if visible on MRI. Toxicity and QoL was assessed prospectively using validated questionnaires. Results Median follow-up was 23 months. The 2-year actuarial biochemical control rate was 100%. Median PSA nadir was 0.6 ng/ml. Median International Prostate Symptoms Score (IPSS) was 9/35 before treatment, with a median increase of 4 at 3 months and remaining stable at 13/35 thereafter. The EORTC/RTOG toxicity scales showed grade 2 and 3 gastrointestinal (GI) acute toxicity in 12% and 2%, respectively. The late grade 2 GI toxicity was 3% during 24 months FU. Genitourinary (GU) grade 2, 3 toxicity was seen in 15%, 8%, in the acute phase and 10%, 6% at 24 months, respectively. The urinary, bowel and sexual domains of the EORTC-PR25 scales recovered over time, showing no significant changes at 24 months post-treatment. Conclusions SBRT to 38 Gy in 4 daily fractions for low- and intermediate-risk PC patients is feasible with low acute and late genitourinary and gastrointestinal toxicity. Longer follow-up preferably within randomized studies, is required to compare these results with standard fractionation schemes.Radiation Oncology 04/2013; 8(1):84. DOI:10.1186/1748-717X-8-84 · 2.36 Impact Factor