75 research outputs found
Management of early neoplasms and surgical complications of the rectum
No full textColorectal cancer (CRC) is one of the most common cancers in the world and is expected to rise from 1.4 million annually diagnosed patients worldwide in 2012 to 2.4 million patients by 2035. In the Netherlands, currently 13,000 new patients are diagnosed with CRC each year, of which approximately one third have rectal cancer. The prognosis of patients with rectal cancer has improved significantly during the last two decades in the Netherlands. The cornerstone of locoregional treatment is still surgery, and improved quality of resection as well as locally advanced rectal cancer by specialised surgical teams contributed substantially to these improvements. Rectal cancer surgery is complex and requires specific expertise. But despite specialisation and centralisation, there is still a relatively high risk of postoperative complications. In contrast to literature on treatment of rectal cancer, prevention and treatment of short and long-term surgical complications has less extensively been explored. At the time prognosis improves, quality of life and management of treatment related morbidity becomes more and more important. Treatment of rectal cancer requires a multidisciplinary evidenced based approach, in which the treatment related morbidity has to be weighed against the expected health benefit. This thesis starts with a chapter on endoscopic treatment of the precursor lesions of rectal cancer. In the subsequent chapters, several complications after rectal surgery are discussed, focussing on predictive factors, prevention, and evaluation of treatment modalities
Design of an Aberration Correction System for a Deployable Space Telescope
No full textLaunch costs for high-resolution space telescopes for Earth observation can be reduced when the telescope mirrors are made deployable. However, such a system is subject to optical aberrations that decreases image quality. To counter these aberrations, an Aberration Correction System (ACS) is proposed that uses a deformable mirror (DM) which is calibrated by applying image sharpness optimisation. A stochastic gradient descent algorithm is applied to the output of two image detectors, such that the DM deformation can even be optimised during in-orbit scanning operations, without the need for a dedicated wavefront sensor. The effects of different sharpness metrics and algorithm settings have been analysed. With this novel control method, an average Strehl ratio of above 0.9 and 0.8 can be achieved on the central field and extreme field of the primary detector respectively. Also, in-orbit drift effects can be actively compensated without interrupting nominal operations.Deployable Space TelescopeAerospace Engineering | Space Systems Engineerin
Perineal Wound Healing After Abdominoperineal Resection for Rectal Cancer: A Systematic Review and Meta-Analysis Reply
No full textINCIDENCE AND UNEMPLOYMENT DURATION IN THE OLTENIA REGION
No full textIn this paper the author analyzes how identified factors influence the incidence and duration of unemployment spells in the Oltenia Region. The statistical data were obtained from the National Agency for Employment and the analyzed period is 1st January 2008-31st December 2010.unemployment, duration, hazard, employment
Perineal wound healing after abdominoperineal resection for rectal cancer: a systematic review and meta-analysis
No full textImpaired perineal wound healing has become a significant clinical problem after abdominoperineal resection for rectal cancer. The increased use of neoadjuvant radiotherapy and wider excisions might have contributed to this problem. The primary aim of this systematic review with meta-analysis was to determine the impact of radiotherapy and an extralevator approach on perineal wound healing after abdominoperineal resection for rectal cancer. In March 2014, electronic databases were searched. Studies describing any outcome measure on perineal wound healing after abdominoperineal resection for rectal cancer were included. The primary end point was overall perineal wound problems within 30 days after conventional or extralevator abdominoperineal resection with or without neoadjuvant radiotherapy. Secondary end points were primary wound healing, perineal hernia rate, and the effect of biological mesh closure on perineal wound problems. A total of 32 studies were included. The pooled percentage of perineal wound problems after primary perineal wound closure in patients who did not undergo neoadjuvant radiotherapy was 15.3% (95% CI, 12.1-19.2) after conventional abdominoperineal resection and 14.8% (95% CI, 9.5-22.4) after extralevator abdominoperineal resection. After neoadjuvant radiotherapy, perineal wound problems occurred in 30.2% (95% CI, 19.2-44.0) after conventional abdominoperineal resection and in 37.6% (95% CI, 18.6-61.4) after extralevator abdominoperineal resection. Radiotherapy significantly increased perineal wound problems after abdominoperineal resection (OR, 2.22; 95% CI, 1.45-3.40; p < 0.001). After biological mesh closure of the pelvic floor following extralevator abdominoperineal resection with neoadjuvant radiotherapy, the percentage of perineal wound problems was 7.3% (95% CI, 1.5-29.3). Heterogeneity was high for some analyses. Neoadjuvant radiotherapy significantly increases perineal wound problems after abdominoperineal resection for rectal cancer, whereas the extralevator approach seems not to be of significant importanc
Multimodality imaging-based response prediction and monitoring to improve clinical management of gastrointestinal stromal tumours
No full textGastrointestinal stromal tumours (GISTs) are rare mesenchymal neoplasms with a worldwide incidence of one or two per 100,000. The tumours affect the entire gastrointestinal tract, but most commonly the stomach and small intestine. Neoadjuvant tyrosine kinase inhibitors (TKI) are administered in a selection of GIST patients to attain size reduction of the primary tumour and improve chances of complete resection. Response monitoring in GISTs is complex due to the presence of intra- and intertumoral heterogeneity and lack of pathological criteria to define response. Nonetheless, it is of importance to evaluate the efficacy of TKI treatment at an early stage in order to optimise treatment. In particular, early cessation of ineffective treatment is of importance in these patients, preventing unnecessary side-effects and healthcare costs. Medical imaging plays an important role to non-invasively predict and monitor treatment response of GIST patients undergoing TKI-treatment. This thesis aims to improve understanding of contrast-enhanced computed tomography (CE-CT) and 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) PET/CT imaging parameters to allow prediction and monitoring of neoadjuvant treatment response in GIST patients. In Chapter 1, the added value of CE-CT and [18F]FDG-PET imaging for early prediction and monitoring of treatment response in GISTs is investigated by means of a systematic literature review. Results of this study show that heterogeneous enhancement patterns on baseline CE-CT imaging were considered to be predictive for high-risk GISTs, reflecting neovascularisation and the presence of necrosis. Current CE-CT radiographic response criteria (i.e., RECIST 1.1 and Choi) are still lacking sensitivity and are prone to errors when predicting or monitoring treatment response. Metabolic changes on [18F]FDG-PET imaging seem to precede morphological changes in size in GIST lesions and were more strongly correlated with tumour response. Although CE-CT and [18F]FDG-PET can aid in the prediction and monitoring in GIST patients, further research on cost-effectiveness is recommended.Chapter 2 evaluates the efficacy of current radiological response criteria (RECIST 1.1, Choi and tumour volumetry) in predicting response to neoadjuvant systemic therapy, by comparing radiological response criteria with the achieved surgical benefit. Results show that size-based criteria (RECIST 1.1 and volumetry) accurately reflect surgical benefit in GIST patients treated with neoadjuvant systemic therapy (accuracy of 76.3% and 86.6% respectively) and are less prone to scanner and imaging protocol variabilities, when compared to the Choi criteria (68.4%). In addition to volumetry, quantitative radiomic models using CE-CT and [18F]FDG-PET imaging features were trained to predict response at baseline. Preliminary results of this study are described in Chapter 3. The radiomic models presented in this study generally had a poor performance and can therefore not yet be applied in a clinical setting. To improve performance and generalisability, future research should focus on a bigger patient population and harmonisation of acquisition protocols. The conclusion of this thesis supports the utilisation of tumour diameters for radiological response assessment, where RECIST 1.1 response criteria had an accuracy of 80.0% to correctly predict volumetric response after the first response follow-up CE-CT scan. When properly executed, these manual measurements could aid in early surgical decision making.Technical Medicine | Imaging and Interventio
Iatrogenic injury of the urinary tract during salvage procedures for pelvic sepsis: Experience of a national referral centre
No full textAim: This study aimed to determine the incidence, consequences and outcomes of iatrogenic urinary tract injury (IUI) during salvage surgery for pelvic sepsis. Method: Patients who underwent salvage surgery for pelvic sepsis after prior low anterior resection or Hartmann's procedure for rectal cancer were prospectively maintained in a database between 2010 and 2020 and reviewed retrospectively. The primary endpoint was the incidence of IUI. Secondary endpoints were timing of diagnosis (intra- vs. postoperative), reinterventions related to the IUI and healing of IUI. Results: In total 126 consecutive patients were included, and IUI occurred in 13 patients (10%). A ureteric injury occurred in eight patients, bladder injury in four patients and a urethral injury in one patient. All patients with an IUI had radiotherapy as neoadjuvant treatment. The IUI was diagnosed postoperatively in 63% (n = 8/13) with a median duration between surgery and diagnosis of the IUI of 10 days (IQR: 6–15). The median number of reinterventions was five (range 1–31) in the group with a postoperative diagnosis and one (range 0–1) in the group with an intraoperative diagnosis. Four patients required a surgical reintervention, all concerning injuries diagnosed postoperatively. At the end of follow-up, 85% of patients (n = 11/13) had a healed IUI. Conclusion: Iatrogenic urinary tract injury is not uncommon in salvage procedures for pelvic sepsis, even in an experienced tertiary referral centre. Most injuries were diagnosed postoperatively which affects the severity of these complications, emphasising the need to improve intraoperative diagnostic modalities
Quality of life in patients with a perineal hernia
No full textIntroduction: Patients who develop a perineal hernia after abdominoperineal resection may experience discomfort during daily activities and urogenital dysfunction, but the impact on quality of life has never been formally assessed. Materials and methods: Patients who underwent abdominoperineal resection for rectal cancer between 2014 and 2022 in two prospective multicenter trials were included. Primary outcome was defined as median overall scores or scores on functional and symptom scales of the following quality of life questionnaires: 5-level version of the 5-dimensional EuroQol, Short Form-36, and European Organization for Research and Treatment of Cancer QoL Questionnaire Colorectal cancer 29 and 30, Urogenital Distress Inventory-6, Incontinence Impact Questionnaire-7. Results: Questionnaires were available in 27 patients with a perineal hernia and 62 patients without a perineal hernia. The 5-dimensional EuroQol score was significantly lower in patients with a perineal hernia (83 vs 87, p = 0.048), which implies a reduced level of functioning. The median scores of pain-specific domains were significantly worse in patients with a perineal hernia as measured by the SF-36 (78 vs. 90, p = 0.006), the EORTC-CR29 (17 vs. 11, p=<0.001) and EORTC-C30 (17 vs. 0, p = 0.019). Also, significantly worse physical (73 vs. 100, p = 0.049) and emotional (83 vs. 100, p = 0.048) functioning based on EORTC-C30 was observed among those patients. Minimally important differences were found for role, physical and social functioning of the SF-36 and EORTC-C30. The urological function did not differ between the groups. Conclusion: A symptomatic perineal hernia can significantly worsen quality of life on several domains, indicating the severity of this complication.</p
Perineal wound healing after abdominoperineal resection for rectal cancer: a two-centre experience in the era of intensified oncological treatment
No full textIntensified treatment for distal rectal cancer has improved oncological outcome, but at the expense of more perineal wound complications in patients undergoing an abdominoperineal resection (APR). The aim of this study was to analyse perineal wound healing after APR with primary perineal wound closure over time. All patients undergoing APR for primary rectal cancer with primary wound closure between 2000 and 2013 were included and analysed in three consecutive time periods. Both early ( <30 days postoperatively) and late perineal wound complications were determined. Independent risk factors of early perineal wound complications were identified using multivariable analysis. A total of 136 patients were identified, of whom 129 patients underwent primary perineal wound closure. The use of neo-adjuvant (chemo)radiotherapy increased from 72 to 91%, and the use of an extralevator approach increased from 9 to 19%. The rate of early perineal wound complications increased from 18 to 31% and was independently associated with an extralevator approach [odds ratio (OR) 3.17; 95% confidence interval (CI) 1.16-8.66] and intra-operative perforation (OR 3.35; 95% CI 1.06-10.57). Perineal wound complications had no impact on local recurrence or 3-year overall survival rate. During a median follow-up of 28 months [interquartile range (IQR) 14-56], a persistent presacral sinus was diagnosed in 10%, and a perineal hernia occurred in 8% of the patients. The increased use of an extralevator APR for rectal cancer significantly increased the risk of perineal wound complications over time. Intra-operative perforation was also independently associated with impaired perineal wound healin
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