Interfraction Anatomical Variability Can Lead to Significantly Increased Rectal Dose for Patients Undergoing Stereotactic Body Radiotherapy for Prostate Cancer.

Interfraction Anatomical Variability Can Lead to Significantly Increased Rectal Dose for Patients Undergoing Stereotactic Body Radiotherapy for Prostate Cancer. Technol Cancer Res Treat. 2016 May 18; Authors: Wahl M, Descovich M, Shugard E, Pinnaduwage D, Sudhyadhom A, Chang A, Roach M, Gottschalk A, Chen J Abstract Stereotactic body radiotherapy for prostate cancer is rapidly growing in popularity. Stereotactic body radiotherapy plans mimic those of high-dose rate brachytherapy, with tight margins and inhomogeneous dose distributions. The impact of interfraction anatomical changes on the dose received by organs at risk under these conditions has not been well documented. To estimate anatomical variation during stereotactic body radiotherapy, 10 patients were identified who received a prostate boost using robotic stereotactic body radiotherapy after completing 25 fractions of pelvic radiotherapy with daily megavoltage computed tomography. Rectal and bladder volumes were delineated on each megavoltage computed tomography, and the stereotactic body radiotherapy boost plan was registered to each megavoltage computed tomography image using a point-based rigid registration with 3 fiducial markers placed in the prostate. The volume of rectum and bladder receiving 75% of the prescription dose (V75%) was measured for each megavoltage computed tomography. The rectal V75% from the daily megavoltage computed tomographies was significantly greater than the planned V...
Source: Technology in Cancer Research and Treatment - Category: Cancer & Oncology Authors: Tags: Technol Cancer Res Treat Source Type: research

Related Links:

For men, the top four cancers, after prostate cancer, are lung, colorectal, bladder, and melanoma, an oncologist says. Here's what men need to know.
Source: WebMD Health - Category: Consumer Health News Source Type: news
CONCLUSIONS: Higher dose volumes for the bladder and rectum predicted for poorer PR-QOL. In contrast to prostate brachytherapy data, neither prostate volume nor urethral dosimetry at this dose schedule correlated with urinary symptoms. PMID: 31584457 [PubMed - as supplied by publisher]
Source: Clinical Prostate Cancer - Category: Cancer & Oncology Authors: Tags: Am J Clin Oncol Source Type: research
CONCLUSION: Empirical validation of dose accumulation in MR-guided SBRT for prostate cancer obtained a good agreement with reference film measurements when using a contour-based DIR approach. PMID: 31585817 [PubMed - as supplied by publisher]
Source: Radiotherapy and Oncology : journal of the European Society for Therapeutic Radiology and Oncology - Category: Radiology Authors: Tags: Radiother Oncol Source Type: research
Conclusions: Based on daily diagnostic quality CT imaging and voxel-wise dose accumulation, we demonstrated for the first time that daily, but not weekly imaging resulted in only negligible deviations of the applied from the planned doses for prostate intensity-modulated radiotherapy. Therefore, weekly imaging may not be adequately reliable for adaptive treatment delivery techniques for prostate. This work will contribute to devising adaptive re-planning strategies for prostate radiotherapy.
Source: Frontiers in Oncology - Category: Cancer & Oncology Source Type: research
Dose-wall histograms (DWHs) have been used as alternatives to dose-volume histograms (DVHs) for hollow organs, with the rationale that the dose delivered to the interior of a hollow organ would be unrelated to the level of radiation damage. The purpose of this study is to conduct a statistical comparison of dose statistics for both walled and solid structure contours for both bladder and rectum in the treatment of intermediate risk prostate cancer with volumetric arc therapy (VMAT). Ten intermediate risk prostate cases were randomly selected.
Source: Medical Dosimetry - Category: Radiology Authors: Source Type: research
Abstract MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression post-transcriptionally responsible for regulating>70% of human genes. MicroRNA-708 (miR-708) is encoded in the intron 1 of the Odd Oz/ten-m homolog 4 (ODZ4) gene. Numerous researches have confirmed that the abnormal expressed miR-708 is involved in the regulation of multiple types of cancer. Notably, the expression level of miR-708 was higher in lung cancer, bladder cancer (BC) and colorectal cancer (CRC) cell lines while lower in hepatocellular carcinoma (HCC), prostate cancer (PC), gastric cancer (GC) and so on. This review pr...
Source: Cellular Signalling - Category: Cytology Authors: Tags: Cell Signal Source Type: research
In this study we calculate composite dose delivered to the prostate by using the Calypso tracking -data- stream acquired during patient treatment in our clinic. We evaluate the composite distributions under multiple simulated Calypso tolerance level schemes and then recommend a tolerance level. MATERIALS AND METHODS: Seven Calypso-localized prostate cancer patients treated in our clinic were selected for retrospective analysis. Two different IMRT treatment plans, with prostate PTV margins of 5 and 3 mm respectively, were computed for each patient. A delivered composite dose distribution was computed from Calypso ...
Source: Journal of Applied Clinical Medical Physics - Category: Physics Authors: Tags: J Appl Clin Med Phys Source Type: research
Stereotactic body radiation therapy (SBRT) is capable of delivering very large and precise dose of radiation, and has emerged as a primary treatment for low and intermediate risk prostate cancer [1,2]. Accurate imaging and tracking of the target regions allows clinicians to reduce treatment margins and maximally spare rectum, bladder, urethra and penile bulb [3]. However, very sharp dose gradients and the proximity of critical structures to prostate requires precise verification of treatment plans [4,5].
Source: Physica Medica: European Journal of Medical Physics - Category: General Medicine Authors: Tags: Original paper Source Type: research
ConclusionDifferent medical physicists or dosimetrists, photon energies, treatment planning systems, and treatment machines have an impact on the resulting dose distribution. However, the differences only become apparent when comparing DVH, analysing dose values, comparing CI, HI, GI, as well as reviewing the dose distribution in every single plane. A  new score was introduced to identify treatment plans that simultaneously deliver a low dose to all OAR. Such inter- and intra-institutional comparison studies are needed to explore different treatment planning strategies; however, there is still no automatic soluti...
Source: Strahlentherapie und Onkologie - Category: Cancer & Oncology Source Type: research
Permanent seed prostate brachytherapy as monotherapy is a highly effective treatment option for men with low- and intermediate-risk prostate cancer, with long-term cancer control rates of 90% or higher. It has the convenience of a single treatment but often results in moderate urinary tract symptoms over a few months while the radiation is being delivered. Furthermore, seed loss or displacement can lead to suboptimal dosimetry, including cold areas within the prostate and higher dose than intended to urethra, rectum, and bladder.
Source: International Journal of Radiation Oncology * Biology * Physics - Category: Radiology Authors: Tags: Clinical Investigation Source Type: research
More News: Bladder Cancer | Brachytherapy | Cancer | Cancer & Oncology | Colorectal Cancer | CT Scan | Prostate Cancer | Toxicology