ORCID Profile
0000-0003-2094-2380
Current Organisation
Royal Brisbane and Women's Hospital
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Publisher: Elsevier BV
Date: 11-2012
Publisher: American Educational Research Association (AERA)
Date: 06-2001
DOI: 10.3102/10769986026002133
Abstract: Available variance component tests are reviewed and three new score tests are presented. In the first score test, the asymptotic normal distribution of the test statistic is used as a reference distribution. In the other two score tests, a Satterthwaite approximation is used for the null distribution of the test statistic. We evaluate the performance of the score tests and other available tests by means of a Monte Carlo study. The new tests are computationally relatively cheap and have good power properties.
Publisher: Elsevier BV
Date: 04-2017
Publisher: Springer Science and Business Media LLC
Date: 22-09-2016
Publisher: British Institute of Radiology
Date: 07-2016
DOI: 10.1259/BJR.20150910
Publisher: Wiley
Date: 11-01-2017
DOI: 10.1002/IJC.30579
Abstract: Human papillomaviruses (HPVs) are the necessary cause of most cervical cancers, a large proportion of other anogenital cancers, and a subset of oropharyngeal cancers. The knowledge about HPV has led to development of novel HPV-based prevention strategies with important impact on clinical and public health practice. Two complementary reviews have been prepared following the 2015 Eurogin Conference to evaluate how knowledge about HPV is changing practice in HPV infection and disease control through vaccination and screening. This review focuses on screening for cervical and anal cancers in increasingly vaccinated populations. The introduction of HPV vaccines a decade ago has led to reductions in HPV infections and early cancer precursors in countries with wide vaccination coverage. Despite the high efficacy of HPV vaccines, cervical cancer screening will remain important for many decades. Many healthcare systems are considering switching to primary HPV screening, which has higher sensitivity for cervical precancers and allows extending screening intervals. We describe different approaches to implementing HPV-based screening efforts in different healthcare systems with a focus in high-income countries. While the population prevalence for other anogenital cancers is too low for population-based screening, anal cancer incidence is very high in HIV-infected men who have sex with men, warranting consideration of early detection approaches. We summarize the current evidence on HPV-based prevention of anal cancers and highlight important evidence gaps.
Publisher: Wiley
Date: 26-01-2020
DOI: 10.1111/ANS.15702
Abstract: Hepatocellular adenoma (HCA) is a hepatocyte derived neoplastic lesion with an increasing incidence and a strong association with oestrogen therapy. Laparoscopic resection has proven safe for small, non-ruptured lesions whilst its use for large adenomas (≥10 cm) and cases of haemorrhage requires further investigation. All patients undergoing liver resection for HCA at the Royal Brisbane Hospital between January 2003 and April 2018 were analysed. Ethics approval was obtained. Thirty-three laparoscopic and three open resections were performed in 35 patients, all female, with a median age of 35 years (range 14-75). Nine laparoscopic resections were performed for large adenomas (≥10 cm) and 17 laparoscopic resections were performed for adenomas of intermediate size (5-9.9 cm). Only one conversion to open surgery was required for an intermediate sized tumour. Haemorrhage, either intratumoural, intraparenchymal or free intraperitoneal was the indication for resection in six of the 33 laparoscopic cases. Median operative time was 143 and 266 min for laparoscopically resected intermediate and large lesions, respectively. The median length of stay was 5 days (range 4-9) and no major complications were observed in the laparoscopic group. β-catenin mutation was seen in four of nine large adenomas whereas the inflammatory subtype constituted 11 of 17 intermediate sized lesions. Laparoscopic surgery has been demonstrated to be safe for the resection of HCA in this group of patients. Importantly, haemorrhage and/or large size were not barriers to laparoscopic resection.
Publisher: Elsevier BV
Date: 11-2016
Publisher: Wiley
Date: 16-04-2018
DOI: 10.1111/ANS.14516
Publisher: Informa UK Limited
Date: 09-02-2019
DOI: 10.1080/01635581.2018.1560479
Abstract: Despite improvements in safety of hepatic resection post-operative complications occur in up to a half of patients. A systematic review was undertaken to compare the effect of pre-operative and peri-operative nutritional supplementation on post-operative outcomes in patients undergoing hepatic resection for malignancy. Included studies were identified through a search of PubMed (1966 to November 2016), Embase (1947 to November 2016) and the Cochrane Library (1993 to November 2016). Eleven studies involving a total of 725 patients were included in this systematic review. BCAA supplementation in the pre-operative and peri-operative period was reported to reduce the overall complication rate by 26.9% (P = 0.01) in one cohort study while pre-operative immunonutrition was shown to reduce post-operative ascites by 25.4% (P =0.012) in another cohort study without affecting the overall complication rate. Four further studies on enteral supplementation failed to show a benefit with regards to post-operative complications. Post-operative mortality was unaffected by pre-operative and peri-operative BCAA. Both pre-operative and peri-operative nutritional supplementation have shown promising results regarding the post-operative course of patients undergoing hepatic resection for malignancy. No randomized controlled study exists directly comparing pre-operative and peri-operative nutrition and this needs to be focused on in future research.
Publisher: Wiley
Date: 14-04-2016
DOI: 10.1111/ANS.13557
Publisher: Elsevier BV
Date: 12-2019
Publisher: Wiley
Date: 30-05-2016
DOI: 10.1002/JSO.24311
Abstract: Patients with in-transit melanoma metastasis have longer median survival than patients with distant metastatic disease. Furthermore, local disease control is an important endpoint for symptom management. The treatment of unresectable loco-regional recurrence or in-transit disease has been historically managed with a combination of treatments including surgery, radiotherapy, isolated limb infusion or perfusion as well as systemic therapies. Intralesional PV-10 has been used at Peter MacCallum Cancer Centre since 2010, and the current report presents a retrospective analysis of patient outcomes, reporting the response rates, durability of responses, and observed toxicities. Records were analyzed retrieving details of 19 patients treated with PV-10 over a 4-year period from 2010 to 2014. Medical records were reviewed for these patients and data extracted. Nineteen patients with in-transit melanoma were treated with intralesional PV-10 between 2010 and 2014. Disease control (complete or partial response or disease stability) was achieved in 68% of patients with 26% having a complete response. This was achieved with minimal associated toxicity. PV-10 is an effective, durable, well-tolerated treatment tool with an acceptable side effect profile for the management of unresectable in-transit melanoma. J. Surg. Oncol. 2016 :380-384. © 2016 Wiley Periodicals, Inc.
Publisher: Wiley
Date: 2016
DOI: 10.1111/IMJ.12955
Publisher: American Association for Cancer Research (AACR)
Date: 2016
DOI: 10.1158/1055-9965.EPI-15-0592
Abstract: Background: We aimed to predict the long-term colorectal cancer incidence, mortality, and colonoscopy demand of the recently implemented Dutch colorectal cancer screening program. Methods: The Adenoma and Serrated pathway to Colorectal Cancer model was set up to simulate the Dutch screening program consisting of biennial fecal immunochemical testing combined with the new Dutch surveillance guidelines, between 2014 and 2044. The impact of screening and surveillance was evaluated under three sets of natural history assumptions differing in the contribution of the serrated pathway to colorectal cancer incidence. In sensitivity analyses, other assumptions concerning the serrated pathway were varied. Model-predicted outcomes were yearly colorectal cancer incidence, mortality, and colonoscopy demand per year. Results: Assuming an aging population, colorectal cancer incidence under 30 years of screening is predicted to decrease by 35% and 31% for a contribution of 0% and 30% of the serrated pathway to colorectal cancer, respectively. For colorectal cancer mortality, reductions are 47% and 45%. In 2044, 110,000 colonoscopies will be required annually assuming no contribution of the serrated pathway (27 per 1,000 in iduals in the screening age range). Including the serrated pathway influences predicted screening effectiveness if serrated lesions are neither detected nor treated at colonoscopy, and/or if colorectal cancers arising from serrated lesions have substantially lower survival rates than those arising from adenomas. Conclusions: The Dutch screening program will markedly decrease colorectal cancer incidence and mortality but considerable colonoscopy resources will be required. Impact: Predictions of long-term screening effectiveness are preferably based on both pathways to colorectal cancer to transparently describe the impact of uncertainties regarding the serrated pathway on long-term predictions. Cancer Epidemiol Biomarkers Prev 25(1) 135–44. ©2015 AACR.
Publisher: Wiley
Date: 14-04-2016
DOI: 10.1111/ANS.13570
Publisher: Elsevier
Date: 2020
Publisher: Wiley
Date: 13-12-2019
Publisher: Elsevier BV
Date: 05-2015
DOI: 10.1016/J.JSE.2014.09.037
Abstract: Conservative management for uncomplicated displaced clavicle fractures is common practice. Delay of surgical fixation may result in less favorable outcomes. A retrospective cohort study was conducted of 60 patients with a closed mid-third clavicle fracture that did not meet current operative or nonoperative guidelines 20 primary (plate fixation 6 weeks), and 20 matched conservative patients were included. Each patient completed 2 questionnaires, the Disabilities of the Arm, Shoulder, and Hand and the American Shoulder and Elbow Surgeons, as well as visual analog scales for pain, cosmetic satisfaction, and overall satisfaction. In addition, 10 patients from each group underwent clinical review of scapular rotation by the lateral scapular slide test, clinical impingement, range of motion assessment, and radiologic review of clavicle union and length. The American Shoulder and Elbow Surgeons patient self-reported questionnaire demonstrated a median score of 5.5 for the delayed group, 2 for the primary group, and 1 for the conservative group (P = .032). The median Disabilities of the Arm, Shoulder, and Hand score was 7.92 for the delayed group, 3.32 for the primary group, and 1.67 for the conservative group (P = .212). Six patients in the delayed group had scapular malrotation compared with 2 in the primary group and none in the conservative group (P = .008). Flexion and external rotation in 90° abduction were decreased in the conservative group (P = .049 and .041, respectively). We support the conservative management of uncomplicated displaced clavicle fractures but recognize that a lower threshold for early surgery should be considered where optimal shoulder function is required.
No related grants have been discovered for Johannes Berkhof.