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Query: UMLS:C0376358 (prostate cancer)
 59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Radiation oncology has undergone rapid technical development during the last few years. The further development of treatment planning systems and treatment machines had a major impact on the improvement of radiation therapy results in prostate cancer. This paper presents different treatment modalities and results. Currently available are three-dimensional conformal radiation, intensity modulated radiation therapy (IMRT), high dose rate brachytherapy, and low dose rate brachytherapy (seed implantation). All modalities offer the possibility for dose escalation, which is essential for curative treatment. Dose escalation using these techniques makes it possible to reduce the dose for the surrounding organs at risk. Three-dimensional conformal radiation therapy can be delivered with doses up to 78 Gy. The biochemical control rate is up to 90% depending on the risk factors T stage, initial PSA, and Gleason score. The incidence of late side effects is <10%. IMRT is a newer modality for percutaneous radiotherapy. By individual dose modification in the treatment fields, doses >80 Gy can be delivered in small treatment volumes. Treatment has to be highly precise to avoid dose peaks in the organs at risk, i.e., rectum and bladder. The preliminary data for remission and toxicity rates are promising, but it is too early for final conclusions. For cases with high-risk factors such as PSA >10 ng/ml, Gleason score >6, and stage T3, percutaneous radiation can be combined with neoadjuvant or adjuvant hormonal treatment. Randomized trials showed an improvement of the results in favor of combined treatment. HDR brachytherapy in combination with external radiation is a good option for dose escalation in patients with locally advanced tumors and/or other high-risk factors. The biochemical control rates are between 60 and 84%, late effects occur in less than 10%. Seed implantation (LDR brachytherapy) as sole treatment is indicated for prognostically favorable situations (PSA <10 ng/ml, Gleason score < or =6, and T1c or T2a tumors). The biochemical control rates are between 80 and 90%. Toxicity consists of urine retention and proctitis, occurring in 10-20% of the patients.
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PMID:[Curative radiotherapy of localized prostate cancer. Treatment methods and results]. 1450 54

Even in the modern era of advanced external radiotherapy, brachytherapy is an important and useful modality of radiotherapy. In North America and Europe, it has been noted that the proportion of prostate cancer patients treated by HDR or LDR interstitial brachytherapy is rapidly increasing, as it offers several practical and theoretical advantages over external radiotherapy. HDR treatment with 192Ir remote afterloader provides an optimized dose distribution controlled by an accurate dwell time and position of 192Ir source. LDR brachytherapy is a simple, minimally invasive, and outpatient based procedure that avoids hospitalization and allows the patient an early recovery and rapid return to normal activities. It has produced good 10-year outcome with relatively low morbidity. Although in Japan this treatment was behind North America and Europe, the 125I-seed source was approved by the Japanese FDA and a rule for patient discharge was developed recently. The first case was treated in September 2003 and this treatment is expected to become an important option for early prostate cancer. Several areas of brachytherapy including treatment planning, choice of radionuclide, treatment procedure, and treatment outcome are discussed in this paper.
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PMID:[Advances in brachytherapy--focusing on the permanent implant for early prostate carcinoma]. 1471 65

Self-reported symptoms including urinary, bowel and sexual side effects were investigated prospectively at multiple assessment points before and after combined radiotherapy of prostate cancer including HDR brachytherapy and neoadjuvant androgen deprivation therapy. Between April 2000 and June 2003, patients with predominantly advanced localized prostate tumours subjected to this treatment were asked before treatment and on follow-up visits to complete a questionnaire covering urinary, bowel and sexual problems. The mainly descriptive analyses included 525 patients, responding to at least one questionnaire before or during the period 2-34 months after radiotherapy. Adding androgen deprivation before radiotherapy significantly worsened sexual function. During radiotherapy, urinary, bowel and sexual problems increased and were reported at higher levels up to 34 months, although there seemed to be a general tendency to less pronounced irritative bowel and urinary tract symptoms over time. No side effects requiring surgery were reported. Classic late irradiation effects such as mucosal bleeding were demonstrated mainly during the second year after therapy, but appear less pronounced in comparison with dose escalated EBRT series. In conclusion, despite the high radiation dose given, the toxicity seemed comparable with that of other series but long term (5-10 years) symptom outcome has to be determined.
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PMID:Combined curative radiotherapy including HDR brachytherapy and androgen deprivation in localized prostate cancer: a prospective assessment of acute and late treatment toxicity. 1616 23

The aim of this study was to focus on certain characteristic problems associated with Iridium-192 high dose-rate brachytherapy (Ir-192 HDR-BT) in combination with external beam radiation therapy (EBRT) in the treatment of patients with localised prostate cancer. Over a period of 16 years, >2,000 patients with prostate cancer have been treated in Sweden with a combination of two fractions of 10 Gy Ir-192 HDR-BT and 50 Gy of fractionated EBRT. Although this treatment is usually well tolerated, there are biological and technical factors to be considered before and during the treatment of the patient to avoid side effects or under-treatment of the target volume. Some of the problems facing the doctors are transducer stability, needle deviation, target definition, target motion, pubic arch interference, concomitant diseases and tolerance doses for different organs at risk. These problems are discussed and possible solutions are presented in this study.
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PMID:High dose-rate brachytherapy of prostate cancer utilising Iridium-192 after-loading technique: technical and methodological aspects. 1708 91

It was the aim of the study to verify dose delivered in urethra and rectum during High Dose Rate brachytherapy boost (HDRBB) of prostate cancer patients. During the first fraction of HDRBB measurement catheters were placed in the urethra and rectum of prostate cancer patients. These contained LiF:Mg,Ti Thermoluminescence Dosimetry (TLD) rods of 1 mm diameter, with up to 11 detectors positioned every 16 mm separated by radio-opaque markers. A Lorentzian peak function was used to fit the data. Measurements from 50 patients were evaluated and measured doses were compared with predictions from the treatment planning system (Plato Vs 13.5 to 14.1). Prospective urinary and rectal toxicity scores were collected following treatment. In more than 90% of cases, the Lorentzian peak function provided a good fit to both experimental and planning urethral data (r2 > 0.9). In general there was good agreement between measured and predicted doses with the average difference between measured and planned maximum dose being 0.1 Gy. No significant association between dose and any clinical endpoints was observed in 43 patients available for clinical evaluation. An average inferior shift of 2 mm between the plan and the measurement performed approximately 1 hour after the planning CT scan was found for the dose distribution in the cohort of patients for the urethra measurements. Rectal measurements proved to be more difficult to interpret as there is more variability of TLD position between planning and treatment. TLD in-vivo measurements are easily performed in urethra and rectum during HDR brachytherapy of prostate patients. They verify the delivery and provide information about the dose delivered to critical structures. The latter may be of particular interest if higher doses are to be given per fraction such as in HDR monotherapy.
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PMID:Thermoluminescence dosimetry for in-vivo verification of high dose rate brachytherapy for prostate cancer. 1804 1

HDR monotherapy for prostate cancer consists of four fractions. The first fraction is delivered with online TRUS-based treatment planning. For the last three fractions the treatment plan is based on a CT-scan acquired in between fractions 1 and 2. The patient position (high lithotomy, rectal US probe) during TRUS-guided catheter implantation and first fraction differs from the patient position in the CT-scan and the remaining three fractions (lowered legs, no TRUS probe). This study describes the effect of posture changes on dose distributions when a plan designed for the TRUS anatomy is applied to the CT-scan anatomy. The aim is to quantify dosimetrical errors that would result from skipping the use of a planning CT-scan, and rely for all fractions on the TRUS plan. Such a procedure would substantially reduce the involved workload, and would increase patient comfort. For three prostate cancer patients, images were acquired during TRUS-guided catheter implantation. Furthermore, a CT-scan (no US probe in rectum, different position of legs) was acquired and matched with the TRUS set. On both TRUS and CT, prostate, urethra and rectum were delineated and all catheters were traced. For each patient, an optimized treatment plan was designed using TRUS images and contours. Catheters with obtained dwell positions of the TRUS plan were transferred individually to the catheter positions in the CT. Changes in dose distribution due to relocation of catheters were evaluated using DVHs. For all patients the dose distributions changed significantly due to rearrangement of the catheters, having most impact on the urethra (maximum observed change: 32% volume receiving > or = 120% of the prescribed dose) and a reduction of PTV coverage (6-28%). Implant deformation when changing from TRUS patient set-up to CT set-up affected negatively the quality of optimized treatment plans. Inclusion of more patients in this study was planned, but because of the observed strong negative effects it is already concluded that the TRUS plan cannot be used for the last three fractions with a deviating patient set-up.
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PMID:HDR prostate monotherapy: dosimetric effects of implant deformation due to posture change between TRUS- and CT-imaging. 1805 1

Prostate cancer (PCA) is the most frequent onlocological disease in men. Every year there are ca. 202.000 new cases of prostate cancer in Europe. Curative treatment of this carcinoma via brachytherapy is becoming increasingly significant (20-30% of all curative approaches). Initial staging and thus allocation to risk groups prior to the commencement of therapy is esspecially important for successful brachytherapy treatment.Low-dose-rate (LDR) brachytherapy (i.e. SEED implantation) distinguishes itself both with respect to the procedure as well as the indication from high-dose-rate brachytherapy (afterloading procedure). Both treatment procedures are employed as monotherapy as well as in combination with external radiation.LDR monotherapy is reported to achieve biochemically relapse-free outcome of up to 90% in low-risk tumours during 10-year follow-up periods. Combined HDR tele- and brachytherapy is reported to achieve a biochemically relapse-free outcome of 80-90% with intermediate- and high-risk tumours in long-term follow-up.While randomized studies are as yet missing, it is still possible to derive the following application algorithms from monitoring studies and cohort studies: application of LDR monobrachytherapy must be restricted to low-risk tumorus. Combined HDR tele- and brachytherapy can be sucessfully applied in cases of intermediate- and high-risk tumours. The outcome depends significantly on the initial, pre-therapy PSA value and Gleason score. Posttherapeutically, the nadir value is crucial with respect to predicting the biochemically relapse-free outcome.
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PMID:[Brachytherapy of the prostate cancer]. 1828 55

High-dose-rate brachytherapy (HDR-BT) to treat prostate cancer is usually performed with the patient under general or spinal anesthesia. This report describes how patients tolerate HDR-BT under local anesthesia and provides technical detail, quantifies discomfort level, and summarizes time required for the procedure. Eleven patients with locally advanced prostate cancer, classified as intermediate or high risk, were treated based on an institutional protocol combining HDR-BT and hypofractionated external-beam radiotherapy. For HDR-BT treatments, patients submitted to two weekly implants. To date, we have performed 22 implantations in 11 patients. The dose of lidocaine administered ranged from 250 to 500 mg (median, 300 mg) and pain score ranged from 2 to 6 (median, 3-4). We conclude that HDR-BT for prostate cancer with the patient under local anesthesia is efficient in terms of resource use and personnel time and will facilitate and expand the use of HDR-BT at our institution and others with few beds.
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PMID:Interstitial high-dose-rate brachytherapy and local anesthesia for prostate cancer: a feasibility report. 1836 73

High dose rate brachytherapy (HDR-BT) is one of the many modalities for prostate cancer treatment. Due to the nature of HDR-BT, in vivo dosimetry is feasible and can be used to verify consistent dose delivery. In order to validate a dose verification system for HDR-BT prostate cancer treatment, a radiophotoluminescent glass dosimeter (RPLGD) was used and the measurements were compared with those from a thermoluminescent dosimeter. The RPLGD shows many advantages in HDR-BT dose measurement, such as repeatability, stability, and small effective size. These advantages make the RPLGD a superior option for use as a dosimeter in HDR-BT. The results described here show that the difference between the measured dose and the treatment planned dose is less than 5%. A Monte Carlo simulation for the dose was performed using Monte Carlo N -particle to investigate position error. This study concludes that the RPLGD is a promising and reliable dosimeter for HDR-BT in vivo dosimetry with clinically acceptable accuracy.
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PMID:Clinical application of radiophotoluminescent glass dosimeter for dose verification of prostate HDR procedure. 1917 13

A phantom study for dosimetry in the urethra using alanine/ESR during (192)Ir HDR brachytherapy of prostate cancer is presented. The measurement method of the secondary standard of the Physikalisch-Technische Bundesanstalt had to be slightly modified in order to be able to measure inside a Foley catheter. The absorbed dose to water response of the alanine dosimetry system to (192)Ir was determined with a reproducibility of 1.8% relative to (60)Co. The resulting uncertainty for measurements inside the urethra was estimated to be 3.6%, excluding the uncertainty of the dose rate constant Lambda. The applied dose calculated by a treatment planning system is compared to the measured dose for a small series of (192)Ir HDR irradiations in a gel phantom. The differences between the measured and applied dose are well within the limits of uncertainty. Therefore, the method is considered to be suitable for measurements in vivo.
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PMID:In vivo dosimetry in the urethra using alanine/ESR during (192)Ir HDR brachytherapy of prostate cancer--a phantom study. 1938


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