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Biomedical subjects

J Kievit

Publications and source records attributed to J Kievit.

At least 73 records · Page 4Linked to original sources
PubMed1995

Follow-up after colorectal cancer: current practice in The Netherlands.

OBJECTIVE: To assess the current practice of follow-up after operations for colorectal cancer in The Netherlands in comparison with other countries. DESIGN: Postal survey. SETTING: All surgical departments in The Netherlands. MAIN OUTCOME MEASURES: Attitudes of surgeons towards detection and treatment of recurrences after colorectal cancer. RESULTS: Of the 139 questionnaires sent out, 136 (98%) were returned. History taking, physical examination, and colonoscopy for local recurrence and metachronous tumours were used by 90% of the hospitals. Attitudes towards screening for hepatic and pulmonary metastases and regional recurrence varied considerably between hospitals. Similar findings were found in seven surveys from other countries. CONCLUSION: There is no consensus among surgeons regarding the follow-up of patients with colorectal cancer. Randomised controlled trials comparing different follow-up strategies and cost-effectiveness analyses are needed to identify groups of patients that will benefit most from follow-up. Identification of these patients may lead to more agreement between surgeons.

Colorectal Neoplasms↗
PubMed1994

[Surgical strategy in acute or elective sigmoid resection in The Netherlands; survey based on a marketing model].

OBJECTIVE: To gain insight into the operative strategies used by Dutch surgeons for complicated diverticulitis and sigmoid carcinoma, and into the influence of patient risk factors and surgeon's experience on the preferred operative strategy. DESIGN: Descriptive. METHOD: A questionnaire was sent to all 148 members of the Dutch Society of Gastrointestinal Surgery, concerning 32 fictitious patients with sigmoid pathology. It was based on conjoint-analysis, a model used in marketing research. This model analyses qualities that make a product preferable to another product of the same product group. The operative choices were: resection with Hartmann's procedure, resection with primary anastomosis after on-table lavage, or with primary anastomosis only, or no primary resection but diverting stoma only, or some personal technique. The survey focused on experience of the surgeons with the operative procedures, and on treatment choices in four fictitious cases frequently encountered in general surgery. RESULTS: There was little agreement concerning the preferred surgical option for treatment of complicated diverticular disease or sigmoid carcinoma. With the exception of one fictitious young, electively operated 'ideal' patient (resection with primary anastomosis) there is hardly any consensus among the surgeons with respect to preferred treatment. CONCLUSIONS: Reasons to depart from the conceptually optimal treatment (resection and anastomosis) in complicated cases (from the point of view of the surgeon or the patient), and absence of agreement on responsible other treatment could be differences in appraisal of the importance of several risk factors, or differences in acquired decision making strategies. The literature offers no answer to the question which techniques should be preferred under various circumstances.

Adult↗
PubMed1994

[When is echography necessary in the diagnosis of pylorus hypertrophy in young children?].

OBJECTIVE: To determine if ultrasonography is necessary for the diagnosis of pyloric hypertrophy in children and if in (clinical) doubt the ultrasonographic diagnosis of 'pylori hypertrophy' may constitute the indication for operation. SETTING: Leiden University Hospital and Amsterdam Centre for Paediatric Surgery. DESIGN: Retrospective study. METHOD: In the period 1985-1990, 83 children younger than 4 months were operated on for pyloric hypertrophy (group I; 73 of them had been examined by ultrasonography), while 15 underwent sonography because of suspicion of pyloric hypertrophy (group II), without operation. An attempt was made to find clinical and laboratory data that might be an indication of pyloric hypertrophy, and render supplementary ultrasonography unnecessary. RESULTS: In group I, the combination of projectile vomiting, discernible gastric peristalsis after test meal and metabolic alkalosis was present in 34%, while a tumour in the upper abdomen was palpated in 25%; neither finding was present in group II. The sensitivity of one-time ultrasonography was 74%, that including follow-up examination in case of doubt, 82%. The predictive value of an ultrasonographic result positive for 'pyloric hypertrophy' was 98%, that of a negative finding 52%, the accuracy was 84%. CONCLUSION: In children younger than 4 months with the combination of projectile vomiting, gastric peristalsis after test meal and metabolic alkalosis, or with a palpable swelling in the upper abdomen, no ultrasonography is necessary to make the diagnosis of 'pyloric hypertrophy'. In case of clinical doubt, the indication for operation may be based on the result of ultrasonography.

Humans↗
PubMed1994

Choices in oncology: factors that influence patients' treatment preference.

Medical treatment of cancer often entails a trade-off between outcomes of two different attributes: quality of life (QOL) and length of life (LL). This process of weighing advantages and disadvantages seems to be influenced by different factors. The main purposes of this study were (a) to investigate the relative importance of different factors on the trade-off and (b) to explore the relationship between these importance ratings and personal characteristics. We asked 199 patients with cancer to indicate to what degree they consider a number of factors to be of importance if they had to choose between two treatment modalities that differ in their expected outcomes concerning QOL and LL. The seven factors were their age at the time of decision, having a partner, having children, inability to work due to side-effects of the treatment, the nature of the side-effects, disease-related life expectancy and baseline QOL. The results indicate that six of the seven factors were of considerable to great importance when a treatment choice had to be made. The negative effects of treatment on the ability to work did not seem to be a very important consideration. Patient age and education were positively associated with importance ratings.

Adult↗
PubMed1994

Sensitivity and specificity of diagnostic tests in acute maxillary sinusitis determined by maximum likelihood in the absence of an external standard.

This study shows how to obtain maximum likelihood estimates of test sensitivities and specificities in case of lack of an external standard, using the Expectation Maximisation (EM) algorithm. This method is used to compare four diagnostic tests in patients suspected of acute maxillary sinusitis. Data were analyzed from published studies. Antral aspiration is the test with the highest diagnostic value. The diagnostic value of a positive clinical examination (according to explicit criteria) and of a positive radiograph or ultrasound are comparable. A negative radiograph is of more diagnostic value than a negative clinical examination or ultrasound. The width of the confidence intervals may be too small, due to model deviations which may give incorrect standard errors. However, the estimated likelihood ratios adequately reflect the relative value of the diagnostic tests considered, even when the assumption of independence is dropped.

Acute Disease↗
PubMed1994

Follow-up of patients with colorectal cancer. A meta-analysis.

OBJECTIVE: The authors sought to determine whether intensive follow-up improves 5-year survival rates in patients with colorectal cancer who were operated on for cure. SUMMARY BACKGROUND DATA: Intensive follow-up of patients with colorectal cancer is still controversial. The present uncertainty in regard to the value of intensive follow-up could be the result of the absence of prospective randomized studies comparing patients with and without follow-up. METHODS: Studies comparing two follow-up programs of different intensities were identified in the medical literature and were aggregated in a meta-analysis using the "random effects method." Seven nonrandomized studies describing 3283 patients were analyzed. RESULTS: Patients with intensive follow-up did have 9% better 5-year survival rates than did those with minimal or no follow-up, only when intensive follow-up included carcinoembryonic antigen (CEA) assays. In addition, more asymptomatic recurrences were detected and more recurrences were resected in patients with intensive follow-up. CONCLUSIONS: This meta-analysis indicated that intensive follow-up using CEA assays can identify treatable recurrences at a relatively early stage. Treatment of these recurrences appears to be associated with improved 5-year survival rates. However, not all intensive follow-up strategies will be equally effective. Follow-up may yield the best results if diagnostic tests are used only to detect those recurrences that can be operated on with curative intent and when follow-up is "individualized," according to patient characteristics.

Actuarial Analysis↗
PubMed1994

Attitudes towards detection and management of hepatic metastases of colorectal origin: a second look.

In the present study we undertook an international postal survey to assess the current attitudes towards the detection and management of hepatic metastases in colorectal cancer patients, who have been operated on with curative intent. Results of this survey were compared to results of an earlier survey, held in 1985. Both surveys indicate that there is no consensus on the follow-up of patients at risk of hepatic metastases. Especially the interpretation of unexplained rises in carcinoembryonic antigen (CEA) levels leads to much controversy. Only 37% of the hospitals performing liver surgery were willing to perform second-look laparotomies based on CEA only. Also there is no agreement on the maximum number of liver metastases that will justify partial liver resection for cure. Clearly, there is a need for prospective randomized trials on which a more rational policy regarding hepatic metastases in colorectal cancer patients can be based.

Attitude of Health Personnel↗
PubMed1994

Acute maxillary sinusitis in general practice: a decision problem.

OBJECTIVE: This paper describes a qualitative analysis of a decision problem of acute maxillary sinusitis in general practice. The criteria and expected outcomes on which general practitioners (GPs) base their choice of a management strategy are presented. DESIGN: Structured open-ended interviews, all done by the first author, were transcribed, and summarized for each management strategy. These summaries were sent back to the experts for verification. PARTICIPANTS: Eight expert GPs from The Netherlands participated; all had been practising for at least three years, and had conducted postgraduate research into upper respiratory tract infections. RESULTS: There was a high degree of consensus among the eight GPs. While most practitioners generally considered the prevention of complications of therapy more important than the prevention of complications of disease, patients at risk (e.g., the elderly, children, patients with other chronic diseases, and patients in weakened condition) of complications of acute sinusitis (e.g., chronic sinusitis) were considered an exception to this rule, possibly because the complications of sinusitis are more serious than those of its therapy. Major differences between the GPs concerned the timing of decisions (e.g. prescribing antibiotics after 5 or 21 days of complaints while local therapy was used). CONCLUSION: Although this study gives no answer as to which management strategy is optimal, the results served as a basis in the development of the Dutch "Sinusitis in general practice standard". In order further to develop the optimal strategy, in future research, the probabilities and weights attached to the criteria and expected outcomes have to be quantified.

Acute Disease↗
PubMed1992

Ventricular late potentials: another expression of cardiotoxicity of cytostatic drugs in children?

With the aim of finding a sensitive method to detect early anthracycline-induced myocardial damage ultimately resulting in cardiomyopathy, we studied the occurrence of ventricular late potentials, using a signal averaged electrocardiogram, in 68 children with cancer during or after chemotherapy. Ten (15%) of the children showed late potentials; in addition, patients treated with cytostatic drugs had significantly lower voltages of the last 40 ms of the QRS complex (RMS40) and a longer duration of low amplitude signals in the terminal QRS (LAS) than control patients. The occurrence of late potentials was not significantly correlated with anthracycline therapy or dosage, nor with the presence of echocardiographic abnormalities; in none of the patients we found late potentials during therapy with anthracyclines. We therefore conclude that late potentials are not helpful for early detection of myocardial injury. The occurrence of late potentials, however, does show another expression of cardiotoxicity not specifically related to anthracycline therapy. The occurrence of these late potentials may have prognostic significance with regard to the risk of ventricular arrhythmias during longer follow-up of these patients.

Action Potentials↗
PubMed1992

Cost-effectiveness decision analysis of obtaining periapical radiographs of traumatized maxillary incisors.

A long-term decision analysis approach has been applied to the problem of whether or not periapical radiographs should be taken routinely of patients presenting with simple fractures of otherwise asymptomatic maxillary incisors. Information from the literature concerning the accuracy of cold, hot and electrical tests for pulp vitality, combined with data on the accuracy of radiographic diagnosis of periapical pathology, and therefore vitality, has been used in the analysis of the diagnostic problem structured in the form of a decision tree. By adding information concerning the direct costs of examining and treating patients over a 10-year period to the analysis and varying the likely prevalence of periapical lesions in a three-way sensitivity analysis, the following results were arrived at: (1) if the disease prevalence in teenage patients is < 5%, it is economically justifiable to make a visual inspection only and then to proceed with simple restorative treatment; (2) if there is evidence from the clinical examination or patient history that the prevalence of pulp necrosis is between 5% and 50% then, in our case, radiographs were the most appropriate single diagnostic test.

Cost-Benefit Analysis↗
PubMed1990

Utility and cost of carcinoembryonic antigen monitoring in colon cancer follow-up evaluation. A Markov analysis.

The use of carcinoembryonic antigen (CEA) to monitor patients after intentionally curative colon cancer resection can have advantages (improved life expectancy as a result of early detection of recurrences) as well as disadvantages (false-positive CEA rises and early detection of incurable recurrences in asymptomatic patients). This study estimated how the favorable and unfavorable effects of CEA monitoring affect life expectancy and quality of life of colon cancer patients. These effects were simulated using a Markov analysis for which the variables had been defined on the basis of data found in literature. The influence of CEA monitoring on quality adjusted life expectancy appears to be modest and varies, according to the data used, from an average increase of +7 days (+0.3%) to an average decrease of -5 days (-0.09%). This value is dependent, among other things, on patient related variables; the adverse effects especially dominate in older patients with a favorable Dukes' stage of the primary tumor and if operative mortality exceeds 2%. The total cost of CEA monitoring, including diagnosis and therapy performed as a result of true- or false-positive CEA rise, is considerable. High cost and low return leads to a high marginal cost-effectiveness ratio, which varies from $22,963 to $4,888,208 per quality adjusted life year saved. It is concluded that CEA monitoring should not be used for routine following of colon cancer patients, as its advantages have so far been demonstrated insufficiently.

Adult↗
PubMed1990

Effect of peri-operative chemotherapy on the quality of life of patients with early breast cancer.

Since chemotherapy is assumed to have a negative impact on quality of life, the impact of peri-operative chemotherapy on physical, psychological and social well-being and on the activity level of patients with early stage breast cancer was investigated. 24 women received peri-operative chemotherapy and 29 did not. They were interviewed 2 months and at a mean of 12 months post-surgery. Although the treated group reported more fatigue and considered hair loss a severe side-effect, no differences were found in overall physical and physiological well-being, perceived social interaction and activity level at 2 months. 1 year after surgery no differences were found between the two groups. Although no substantial effects of peri-operative chemotherapy on quality of life were demonstrated, patients almost unanimously considered peri-operative chemotherapy the most burdensome aspect of the treatment because of alopecia.

Adult↗
PubMed1989

[Carcinoembryonal antigen and the follow up of patients after resection of colon carcinoma with curative intent: a Markov process in decision analysis].

The follow-up of colon cancer patients by monitoring serum carcinoembryonic antigen has advantages (better survival after early detection of recurrence by CEA rise) as well as disadvantages (false-positive rise of CEA, and early detection of incurable recurrences in asymptomatic patients). The effects of CEA follow-up on quality-adjusted life expectancy (QUALE) of patients with curatively resected colon carcinoma have been simulated by a Markov analysis using literature data. The value of CEA seems insignificant and varies, depending on the literature data used, from a mean increase of QUALE by 6 days (+0.4%) to a mean decrease by 2 days (-0.07%). This value depends on patient-related variables; the negative effects of CEA especially predominate in older patients with favourable Dukes' stages of primary tumour.

Carcinoembryonic Antigen↗
PubMed1983

Standardized diagnosis and treatment of fluid, acid-base and electrolyte disorders in the surgical patient with the aid of a programmable pocket calculator.

The approach to fluid, acid-base and electrolyte disorders in the surgical patient has been standardized in a pocket calculator program that categorizes these disorders into formal diagnoses and subsequently uses these diagnoses to determine the appropriate therapy. The program was tested in 80 infusion regimens of patients in the intensive care and surgical wards. The advantages of a standardized approach to these disorders, using diagnostic and therapeutic algorithms, are briefly discussed.

Aged↗
PubMed1977

Organization of the thalamo-cortical connexions to the frontal lobe in the rhesus monkey.

In 25 rhesus monkeys horseradish peroxidase was injected in different parts of the frontal cortex. The retrogradely labelled thalamic neurons formed longitudinal bands, some of which crossed the internal medullary lamina, and extended from one thalamic nucleus into another. On the basis of these findings the frontal cortex was subdivided into seven transverse cortical strips which receive afferents from seven longitudinal bands of thalamic neurons. The most rostral transverse strip receives afferents from the most medial thalamic band which is oriented vertically and extends through the most medial part of the MD into the medial pulvinar. Progressively more caudally located transverse strips receive afferents from progressively more laterally located thalamic bands which in part are situated in the VL and show an increasing tilt towards the horizontal. Moreover, those parts of the various bands which are situated along the dorsal and lateral margin of the thalamus project to the medial portions of the transverse cortical strips, i.e. along the medial margin of the frontal lobe, while the other parts situated ventromedially in the thalamus project to the lateral portions of these strips, i.e. along the lateral margin of the frontal lobe. These data provide an alternative view of the organization of the thalamus and suggest that this structure contains a matrix of longitudinal cell columns which in some cases extend across specific nuclear borders and may represent the basic thalamic building blocks in respect to the thalamo-cortical connexions.

Animals↗