Prostate brachytherapy is a treatment for prostate cancer; during the planning of the procedure, ultrasound images of the prostate are taken. The prostate must be segmented out in each of the ...ultrasound images, and to assist with the procedure, an autonomous prostate segmentation algorithm is proposed. The prostate contouring system presented here is based on a novel superpixel algorithm, whereby pixels in the ultrasound image are grouped into superpixel regions that are optimized based on statistical similarity measures, so that the various structures within the ultrasound image can be differentiated. An active shape prostate contour model is developed and then used to delineate the prostate within the image based on the superpixel regions. Before segmentation, this contour model was fit to a series of point-based clinician-segmented prostate contours exported from conventional prostate brachytherapy planning software to develop a statistical model of the shape of the prostate. The algorithm was evaluated on nine sets of in vivo prostate ultrasound images and compared with manually segmented contours from a clinician, where the algorithm had an average volume difference of 4.49 mL or 10.89%.
During an ultrasound (US) scan, the sonographer is in close contact with the patient, which puts them at risk of COVID-19 transmission. In this paper, we propose a robot-assisted system that ...automatically scans tissue, increasing sonographer/patient distance and decreasing contact duration between them. This method is developed as a quick response to the COVID-19 pandemic. It considers the preferences of the sonographers in terms of how US scanning is done and can be trained quickly for different applications. Our proposed system automatically scans the tissue using a dexterous robot arm that holds US probe. The system assesses the quality of the acquired US images in real-time. This US image feedback will be used to automatically adjust the US probe contact force based on the quality of the image frame. The quality assessment algorithm is based on three US image features: correlation, compression and noise characteristics. These US image features are input to the SVM classifier, and the robot arm will adjust the US scanning force based on the SVM output. The proposed system enables the sonographer to maintain a distance from the patient because the sonographer does not have to be holding the probe and pressing against the patient's body for any prolonged time. The SVM was trained using bovine and porcine biological tissue, the system was then tested experimentally on plastisol phantom tissue. The result of the experiments shows us that our proposed quality assessment algorithm successfully maintains US image quality and is fast enough for use in a robotic control loop.
Radiotherapy is a mainstay of cancer treatment, used in either a curative or palliative manner to treat approximately 50% of patients with cancer. Normal tissue toxicity limits the doses used in ...standard radiation therapy protocols and impedes improvements in radiotherapy efficacy. Damage to surrounding normal tissues can produce reactions ranging from bothersome symptoms that negatively affect quality of life to severe life-threatening complications. Improved ways of predicting, before treatment, the risk for development of normal tissue toxicity may allow for more personalized treatment and reduce the incidence and severity of late effects. There is increasing recognition that the cause of normal tissue toxicity is multifactorial and includes genetic factors in addition to radiation dose and volume of exposure, underlying comorbidities, age, concomitant chemotherapy or hormonal therapy, and use of other medications. An understanding of the specific genetic risk factors for normal tissue response to radiation has the potential to enhance our ability to predict adverse outcomes at the treatment-planning stage. Therefore, the field of radiogenomics has focused upon the identification of genetic variants associated with normal tissue toxicity resulting from radiotherapy. Innovative analytic methods are being applied to the discovery of risk variants and development of integrative predictive models that build on traditional normal tissue complication probability models by incorporating genetic information. Results from initial studies provide promising evidence that genetic-based risk models could play an important role in the implementation of precision medicine for radiation oncology through enhancing the ability to predict normal tissue reactions and thereby improve cancer treatment.
Purpose
Many patients with advanced cancer receive primary supports from informal caregivers (IC). As patient health deteriorates, IC assume increasing responsibility, often accompanied by distress. ...We investigated the quality of life (QOL) of IC of patients referred to a palliative radiotherapy (PRT) program.
Methods
IC accompanying patients to a dedicated PRT clinic completed a survey based on the validated Caregiver Quality of Life Index-Cancer (CQOLC). Demographics, burden, and engagement in support services were evaluated. Summary statistics were calculated, and parameters were assessed for association with CQOLC scores by a generalized linear model.
Results
Two hundred one surveys were analyzed representing 197 unique patients. The mean age was 68.3 years, with predominantly lung (25.0%) and prostate (19.3%) malignancies. 24.4% had been in hospital/long-term care within the previous 7 days. IC were 60.8% female, and 60.6% were the patient’s spouse. 69.5% lived with the patient and 38.3% were additionally employed. IC spent a daily mean of 6.6 h (SD 7) assisting with instrumental (72.5%) and basic (37.5%) activities of daily living. Mean CQOLC score was 82.1/140 (SD 20). 63.8% of IC had previously accessed support service(s), most commonly home care (37.2%) and pharmacy (29.1%). 55.9% indicated interest in services not yet accessed. Multivariate analysis revealed additional employment, cohabitation, poor patient performance status, and interest in accessing more support services significantly correlated with higher IC burden.
Conclusions
Employing the CQOLC to screen IC of patients referred to a PRT program permits early identification of vulnerable IC to facilitate linkage with appropriate supports.
This study retrospectively reviewed data from men with localized prostate cancer treated with external beam radiotherapy (EBRT). We identified 359 men with localized prostate cancer treated with ...curative EBRT at the Cross Cancer Institute between 2010-2011. The volume of seminal vesicles (SVs) treated as well as dose values were extracted. These volumes were compared to gold standard contours drawn by a trained expert based on consensus European Society for Radiotherapy and Oncology (ESTRO) contouring guidelines. Patient and tumor characteristics were extracted for these patients. Memorial Sloan Kettering prostate cancer nomogram was used to assign a predicted risk of SV involvement for each patient based on baseline tumor characteristics. In patients with a predicted risk of SV involvement greater than 15% (
= 184), 86.5% (SD = 18.6) of the base of the SVs were treated with EBRT, compared to 66.7% (SD = 32.6) for patients with a predicted risk of SV involvement less than 15% (
= 175,
< 0.0001). Similarly, the mean percentage of proximal and total SV volumes treated with EBRT was 75.6% (SD = 24.4) and 68.7% (SD = 26.0) for patients with a predicted risk of SV involvement of greater than 15%, compared to 50.3% (SD = 31.0,
< 0.0001) and 41.0% (SD = 27.8,
< 0.0001) for patients with a risk of less than 15%. The results indicate that all parts of the SVs are more likely to be contoured in men with >15% risk of SV involvement than those with <15% risk. However, radiation oncologists still contour a high percentage of SVs in men with <15% risk of SV involvement, suggesting that there may be over-treatment of SVs that increases the risk of rectal or bladder toxicity.
Purpose
Low-dose-rate permanent-seed (LDR-PS) brachytherapy has shown a great potential for treating breast cancer. An implantation scheme indicating the template pose and needle trajectories is ...determined before the operation. However, when performing the pre-planned scheme intraoperatively, a change of the patient’s posture will cause seed placements away from the desired locations. Hence, the implantation scheme should update based on the current patient’s posture.
Methods
A numerical method of optimizing the implantation scheme for the LDR-PS breast brachytherapy is presented here. The proposed algorithm determines the fewest needle trajectories and template poses for delivering the seeds to the intraoperative desired locations. The clinical demand, such as the minimum distance between the chest wall and the needle, is considered in the optimization process.
Results
The method was simulated for a given LDR-PS brachytherapy procedure to evaluate the optimal scheme as the number of the template poses changing. The optimization parameters of the needles’ number and the implantation errors are used to adjust the algorithm outcome. The results show that the implantation schemes obtained by our method have a satisfactory accuracy in the cases of 2 or 3 template poses. The computation time is about 76s to 150s according to the number of the template poses from 1 to 3.
Conclusion
The proposed method can find the optimal implantation scheme corresponding to the current desired seed locations immediately once there is a change of patient’s posture. This work can be applied to the robot-assisted LDR-PS breast brachytherapy for improving the operation accuracy and efficiency.
In percutaneous needle insertions, cutting forces at the needle tip deflect the needle and increases targeting error. Thus, modeling needle-tissue interaction in biological tissue is essential for ...accurate robotics-assisted needle steering. In this letter, dynamics of needle tip interaction with inhomogeneous biological tissue is described and the effects of insertion velocity, tissue mechanical characteristics, and needle geometry on tissue cutting force are studied. Needle interaction with biological tissue is divided into three distinct events and modeled. 1) Initial tissue puncturing, which starts by soft tissue deformation and continues until a crack is formed in the tissue. Employing a viscoelastic model of fracture initiation we have predicted the maximum puncturing force and force-displacement response of a needle in contact with a tissue. 2) Tissue cutting, which follows the crack propagation in tissue and is predicted using a novel energy-based fracture model. The model takes account of the needle tip geometry and the tissue mechanical characteristics. 3) Friction between tissue and needle shaft is estimated during needle insertion and retraction using a needle-tissue friction model. Using a needle driving robot ex vivo experiments are performed on a porcine tissue sample to identify the model parameters and validate the analytical predictions offered by the models.
To describe treatment options for clinically localized prostate cancer: radical prostatectomy, prostate brachytherapy, external beam radiation, and active surveillance.
Prostate-specific antigen ...(PSA) outcomes presented are from non-randomized, cohort, and other comparisons trials (level II evidence). We describe PSA outcomes from Canadian centres when they are available. One small randomized controlled trial (level I evidence) in localized prostate cancer is available to compare radical prostatectomy with brachytherapy.
Treatment choice in prostate cancer is based on initial PSA level, clinical stage of disease, and Gleason score, together with baseline urinary function, comorbidities, and patient age. In this article, we describe patients' eligibility for and the common side effects of all treatment options. Prostate brachytherapy and active surveillance have evolved as new standard treatments of localized prostate cancer. We give a brief overview of the brachytherapy procedure, side effects, and PSA outcomes across Canada, as well as active surveillance guidelines.
Prostate cancer treatment requires a multidisciplinary approach, with input from both urology and radiation oncology. Input from family physicians is often as important in helping guide patients through the treatment decision process.
Androgen deprivation therapy (ADT) used for prostate cancer (PCa) management is associated with metabolic and anthropometric toxicity. Metformin given concurrent to ADT is hypothesized to counteract ...these changes. This planned interim analysis reports the gastrointestinal and genitourinary toxicity profiles of PCa patients receiving ADT and prostate/pelvic radiotherapy plus metformin versus placebo as part of a phase 2 randomized controlled trial. Men with intermediate or high-risk PCa were randomized 1:1 to metformin versus placebo. Both groups were given ADT for 18-36 months with minimum 2-month neoadjuvant phase prior to radiotherapy. Acute gastrointestinal and genitourinary toxicities were quantified using CTCAE v4.0. Differences in ≥ grade 2 toxicities by treatment were assessed by chi-squared test. 83 patients were enrolled with 44 patients randomized to placebo and 39 randomized to metformin. There were no significant differences at any time point in ≥ grade 2 gastrointestinal toxicities or overall gastrointestinal toxicity. Overall ≥ grade 2 gastrointestinal toxicity was low prior to radiotherapy (7.9% (placebo) vs. 3.1% (metformin), p = 0.39) and at the end of radiotherapy (2.8% (placebo) vs 3.1% (metformin), p = 0.64). There were no differences in overall ≥ grade 2 genitourinary toxicity between treatment arms (19.0% (placebo) vs. 9.4% (metformin), p = 0.30). Metformin added to radiotherapy and ADT did not increase rates of ≥ grade 2 gastrointestinal or genitourinary toxicity and is generally safe and well-tolerated.
Introduction
The study evaluated the effect of chemotherapy dose-capping on disease recurrence, toxicity and survival of rectal cancer patients treated with chemoradiotherapy (CRT).
Methods
601 ...consecutive rectal cancer patients treated with concurrent CRT were retrospectively analysed. Dose-capped patients were defined as having a body surface area (BSA) ≥2.0 m2 and who received <95% full weight-based chemotherapy dose. Binary logistic regression was used to study the factors associated with the outcome variables (capped vs. uncapped). Kaplan-Meier estimation evaluated significant predictors of survival.
Results
The median follow-up time was 7.54 years. The rate of disease recurrence was significantly higher in dose-capped patients (35%) compared to those without dose-capping (24%, P = 0.016). The adjusted odds ratio for dose-capped patients experiencing recurrence was 1.64 compared to uncapped patients (95% CI, 1.10–2.43). Overall, dose-capped patients were less likely to experience significant toxicity requiring dose reduction and/or treatment break when compared to uncapped patients (15% and 28% respectively, P = 0.008).There was significant differences in PFS between capped and uncapped group (77% vs. 85%; P = 0.017). The 5-year OS in the capped group was 75.0%, and 80% in the uncapped group (P = 0.149).
Conclusions
Rectal cancer patients treated with dose-capped CRT were at increased risk of disease recurrence. Patients dosed by actual BSA did experience excessive toxicity compared to dose-capped group. We recommend that chemotherapy dose-capping based on BSA should not be practiced in rectal cancer patients undergoing CRT.
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