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A L Verbeek

Publications and source records attributed to A L Verbeek.

At least 109 records · Page 6Linked to original sources
PubMed1995

Short communication: breast parenchymal patterns and their changes with age.

In studies on mass screening, it has often been reported that tumours in breasts with dense parenchyma are difficult to detect and may have a more advanced stage at diagnosis. Shorter rescreening intervals have been suggested for these women but, before recommending such a strategy, it is important to investigate how often dense breast parenchyma (P2 and DY patterns according to Wolfe) is actually present in a screening population and to what extent these patterns change with age. The prevalence of dense breast parenchyma (P2 and DY) in our study population was 33% at first examination (n = 2581), which is fairly low compared with other screening populations. Its presence was strongly, inversely age-dependent. Breast patterns of 1177 women, aged 35-85 years, were followed for 12 years. In 39% (182/461) of the women with a P2 or DY pattern at their first examination, regression to a lucent pattern (N1 and P1) occurred over the years. The majority of these women were assumed to have reached menopause in the follow-up period. These findings support the hypothesis that the presence of dense breast parenchyma is related to the reproductive period and indicate that shortening the rescreening intervals would be most effective in pre-menopausal age groups.

Adult↗
PubMed1994

Efficacy of mammographic screening of the elderly: a case-referent study in the Nijmegen program in The Netherlands.

BACKGROUND: Only a few small studies have been conducted to examine the usefulness of mammographic screening in elderly women. These studies suggest that the screening-related reduction in breast cancer mortality rates is less than the estimated 20%-40% reduction observed for women aged 50-70 years at the time of their first screening. PURPOSE: We have studied the efficacy of continued mammographic screening for breast cancer of elderly women within our screening program. METHODS: In 1975, a breast cancer screening program was started in the city of Nijmegen. The Netherlands. During each biennial screening round, approximately 30,000 women aged 40 years and older were personally invited to participate. Single-view mammography was administered. The present study was conducted using a case-referent design. In order to be eligible for inclusion in this study, women had to have been invited to participate in the mammography screening program at least twice, with the most recent invitation having occurred when each woman was 65 years or older. The cases studied comprised 33 women in this group who had died of breast cancer at some point during 1977 through 1988. Referents were matched for age at last invitation to screening prior to the diagnosis of breast cancer and for the number of previous invitations to screenings. Five referents were randomly selected for each case. Breast cancer mortality rate ratios (RR) were calculated for several categories of attendance to the screening. RESULTS: The RR of those who attended the last screening versus those who failed to do so was 0.58 (95% confidence interval [CI] = 0.24-1.41); for women aged 65-74, the RR was 0.34 (95% CI = 0.12-0.97) and for women aged 75 or over, 2.87 (95% CI = 0.62-13.2). The RR of those who attended the screening before and after the age of 65, relative to those who attended before 65 only, was 0.26 (95% CI = 0.05-1.32). CONCLUSION: Although self-selection bias was present in our data, it was not likely to be responsible for the beneficial effect in women aged 65-74 at the time of invitation to screenings. It probably was responsible for the reversed RR (RR > 1) in the group of women 75 years and older. IMPLICATION: Continuation of mammographic screening until at least the age of 75 years may lead to a reduction of breast cancer mortality among elderly women.

Age Factors↗
PubMed1994

Age-specific effectiveness of the Nijmegen population-based breast cancer-screening program: assessment of early indicators of screening effectiveness.

BACKGROUND: The benefits of mammographic screening for breast cancer are not clear for women less than 50 years old. PURPOSE: Our aim was to evaluate the effectiveness of breast cancer screening in different age groups. METHODS: A mammographic breast cancer-screening program with a 2-year screening interval has been under way in Nijmegen, The Netherlands, since 1975. After eight rounds, more than 40,000 women have been invited to participate. All breast cancer cases diagnosed in the invited population, whether detected by screening or clinically, have been considered in this study. The age groups are younger than 50 years, 50-69 years, and 70 years or older at last invitation before diagnosis. Our assessment of the effectiveness of screening is based on the proportion of screen-detected cancers among all cancers and on the disease stage at diagnosis. RESULTS: For women younger than 50, compliance was 75%, and 37% (85/230) of the cancers were detected by screening. The age group 50-69 years had a compliance of 65% with 48% (288/595) of cancers detected by screening, and the group 70 years or older had a 25% compliance with 35% (108/305) of cancers detected by screening. The sizes of the cancers detected by screening were smaller than those detected clinically for all age groups. The age group under 50 showed no substantial difference in the proportion of positive axillary lymph node status between screening-detected and clinically diagnosed cancers, while among older women, the proportion of lymph node involvement was substantially higher for clinically detected cases. A significantly lower frequency of advanced stages was observed in screen-detected compared with clinically diagnosed cancers for women 50 years of age or older (P < .001) but not in women under 50 (P = .35). CONCLUSIONS: No positive effect of the biennial screening program is apparent for women under age 50. For women aged 50 and above, the screen-detected cancers have a more favorable stage distribution than clinically diagnosed cancers, a prerequisite for a reduction in breast cancer mortality.

Adult↗
PubMed1994

Mortality trend from prostate cancer in The Netherlands (1950-1989).

The trend in prostate cancer mortality in The Netherlands was studied, using data from the National Causes of Death Registry of the Central Bureau of Statistics. During the period 1950-1989, the age-adjusted mortality rate showed a steady rise from 20.5 to 30.6 per 100,000 man-years. A multiplicative model was used to examine possible period effects and birth-cohort effects separately. This analysis demonstrated that the increase in prostate cancer mortality is largely due to a birth-cohort effect, though calendar time of death may have had a slight effect as well. Among Dutch men, a continuous increase of mortality from prostate cancer was found in consecutive birth cohorts. This finding is in contrast with that of comparable studies in other Western countries, in which a peak mortality rate was found for the cohort born at the end of the 19th century with stabilizing or declining rates for later birth cohorts.

Age Factors↗
PubMed1994

Socioeconomic status, urbanization grade, and prostate cancer.

In a population-based case-referent study, carried out in The Netherlands, the relationship between socioeconomic status (SES) and urbanization grade on the one hand and prostate cancer incidence on the other has been investigated. Two explanations for a potential association have been taken into account. First, there is a relationship with SES class (or with urbanization grade) in the past, referring to an effect on the induction or promotion of prostate cancer caused by variation in exposure to particular risk factors. Second, there is a relationship with current SES (or urbanization grade), resulted in differences in medical screening. Study data were obtained by means of a validated mailed questionnaire, which has been completed and returned by 345 cases (with histologically confirmed prostate cancer) and 1,346 referents (patients with benign prostate hyperplasia). The response was 79%. No clear relationship was observed with SES, based on the major job held between 1960-1970 (the period of cancer induction), nor was this the case with SES based on the longest-held job (as a proxy for current SES). A slight, but statistically nonsignificant, trend was found of higher risks in subjects living in rural areas, with an urban/rural ratio of 0.79. Considering the results of this study and those of previous studies reviewed in this paper, it might be doubted that any relationship is to be found between prostate cancer risk and SES or urbanization grade.

Employment↗
PubMed1994

Efficacy of hydroquinine in preventing frequent ordinary muscle cramp outlasts actual administration.

In order to compare the efficacy of a daily dose of 300 mg hydroquinine hydrobromide and placebo in preventing frequent ordinary muscle cramp, we designed a randomized, double-blind, placebo-controlled study of three consecutive 2-week periods viz. a qualification period, a medication period and a wash-out period. Twenty healthy adult volunteers experiencing at least 3 muscle cramps a week (6 men, 14 women aged 38-78 yrs) were enrolled into this study, and 19 of them completed it. Hydroquinine hydrobromide (300 mg/day) was administered to group 1 (10 women) and placebo to group 2 (4 women, 6 men). The frequency, severity, duration and location of muscle cramps as well as short-term adverse drug effects were recorded in daily diaries. Compared with placebo the decrease in the mean number of muscle cramps (16.1 or 58%) in the active drug treatment group during the medication period was highly significant (Wilcoxon test p = 0.004). During the wash-out period this decrease partly persisted (8.9 or 33%). In this study a daily dose of 300 mg hydroquinine hydrobromide was effective in preventing frequent ordinary muscle cramp in healthy female volunteers. The effects of hydroquinine outlasted its administration. The drug was well tolerated.

Adult↗
PubMed1994

Prognostic assessment from studies with non-randomized treatment assignment.

In clinical practice, prognostic factors are primarily used to identify and select patients with a relatively poor prognosis who may need more aggressive treatment in order to improve their prognosis. Preferably, assessment of the ability of prognostic factors to distinguish these high risk patients from low risk patients should take place in the absence of such prognosis-modifying adjuvant therapy. Adjuvant therapy may dilute the effect of prognosticators (covariate-treatment interactions) and such a situation may go unnoticed in tests for interaction because of their low statistical power. These undetected covariate-treatment interactions will bias the estimated effects of prognostic factors in both studies with randomized and non-randomized treatment assignment but the bias will usually be greater in studies when treatment was not randomized. For the evaluation of prognostic factors, it is therefore argued that the study population should be restricted to patients who do not received adjuvant therapy. This restriction might result in a less powerful analysis, but it carries the advantage that undetectable biases are avoided. Non-random treatment assignment will not invalidate this restriction analysis provided that all the prognostic factors on which treatment choice was based, are known and incorporated into the analysis.

Bias↗
PubMed1994

Prognosis and treatment of T1G3 bladder tumours. A prognostic factor analysis of 121 patients. Dutch South Eastern Bladder Cancer Study Group.

Patients with T1G3 bladder cancer have a considerable risk for recurrence and/or progressive disease. Until now no consensus has been achieved on the optimal treatment. Within the Dutch South Eastern Bladder Cancer Study Group, 155 patients with a T1G3 bladder tumour were seen between 1983 and 1988. After review of histology, 121 could be evaluated and recurrence-free interval was studied with regard to prognostic factors. Prognostic factors such as sex, age, blood group, abnormalities on intravenous urography, pretreatment tumour configuration, number of tumours, number of locations involved in the bladder, voided urine cytology, results of random biopsies and mitotic index were evaluated, using a multivariate analysis with the Cox proportional hazard model. During the follow-up period, 70 (58%) patients had recurrent bladder cancer, and of these 30 (43%) had progression into invasive disease. Of the possible prognostic factors analysed, only multiplicity (P = 0.03) and the number of locations of the tumours (P = 0.03) were independent prognostic factors in relation to the risk of recurrence. The recurrence-free interval was influenced by the therapy. For T1G3 tumours, additional intravesical immunotherapy/chemotherapy or radiotherapy after transurethral resection (TUR) increased the recurrence-free interval significantly. Because most other parameters did not show additional prognostic value, the T1G3 tumours can be considered as homogeneous with regard to prognosis. Only multiplicity and the number of locations involved added to the prognostic significance of patients with these bladder tumours. In addition, it is advisable to give patients with T1G3 tumours additional treatment after the initial TUR.

Adult↗
PubMed1994

Bladder cancer incidence and survival in the south-eastern part of The Netherlands, 1975-1989.

Trends in cancer occurrence and survival may reflect changing risks and prognosis, respectively, but may also be caused by changes in detection, classification and registration. Changed classification of low-stage papillary carcinomas may have a material effect on observed trends in the occurrence of bladder cancer. We studied the effect of the implementation of the WHO grading system and the third edition of the TNM staging system on bladder cancer incidence in the south-eastern part of the Netherlands. Data on superficial and invasive bladder cancer incidence between 1975 and 1989 were derived from the population-based Eindhoven cancer registry. Data on survival of patients with stages I-IV bladder cancer were derived from the municipal population registers. Age-adjusted bladder cancer incidence per 100,000 person-years rose from 25.9 to 40.7 in males and from 3.1 to 8.5 in females. This increasing trend was caused almost entirely by non-invasive pTa papillary carcinoma. A considerable shift was observed towards lower disease stages, which was less evident within the group of invasive tumours. The relative 5-year survival of patients with stages I-IV invasive bladder cancer was 59% in 1975-1977 and 70% in 1984-1986. After stratification by stage, however, no striking improvement was observed in the prognosis. We conclude that the increasing trend of bladder cancer occurrence in the Netherlands since 1975 has largely been caused by changed classification systems and reporting procedures for pTa tumours (formerly classified as papillomas).

Female↗
PubMed1994

Dysplasia in normal-looking urothelium increases the risk of tumour progression in primary superficial bladder cancer.

Random urothelium biopsies were taken at initial endoscopic surgery from 1001 patients with primary superficial bladder cancer. The clinical course of all the patients was assessed prospectively. Actuarial risks of recurrence and disease progression were determined for prognostic characteristics and comparisons were made using log-rank tests. The independent prognostic significance of concomitant intra-aurothelial dysplastic changes was examined with Cox's regression analyses. The 3-year risk of recurrence in patients with dysplasia and carcinoma in situ (CIS) in macroscopically normal-looking urothelium was only slightly higher than the risk in patients without dysplastic changes (56, 58 and 51%, respectively; P = 0.25). Concomitant dysplasia or CIS significantly increased the 3-year risk of disease progression (17 and 31%, respectively, versus 7%; P < 0.001). After adjustment for the effects of age, tumour stage, grade, size and multicentricity, the result of random biopsies had no prognostic significance regarding the risk of recurrence, but the detection of dysplasia or CIS increased the risk of progression by approximately 80%. This result suggests that random urothelium biopsies may be useful as an additional guide in defining therapy in primary superficial bladder cancer.

Adolescent↗
PubMed1994

The capture-recapture method for estimation of cancer registry completeness: a useful tool?

BACKGROUND: In this paper we investigated whether the capture-recapture method is useful for a cancer registry to monitor its completeness of case ascertainment on a routine basis. METHODS: The capture-recapture method was used to estimate the completeness of case ascertainment in three regional cancer registries in the Netherlands, which are based on case finding by pathology laboratories and hospitals. RESULTS: Completeness was estimated to be 98.3%. The estimate of completeness was dependent on age and cancer site, with lower estimates of completeness for skin cancer and lymphatic and haematopoietic malignancies and for the age group > or = 75 years. CONCLUSIONS: A major drawback of the capture-recapture method is its inability to estimate the number of cases that are not routinely notified to the registry by one or both notification sources. Another limitation is the lack of statistical power to detect incompleteness in an early stage. It is concluded that the capture-recapture method is not useful for everyday surveillance of completeness in cancer registration.

Aged↗
PubMed1994

Swimming and the risk of cutaneous melanoma.

Recreational exposure to the sun may not explain fully current trends in melanoma incidence. The hypothesis was examined whether carcinogens in water play a role in the development of cutaneous melanoma. In a case-control study, 128 melanoma patients and 168 patients with other types of malignancy completed a detailed questionnaire on aquatic leisure time activities. All relative risk estimates were adjusted for age, gender, educational level, pigmentation characteristics, and exposure to sun habits. Regular swimming during the summer months in swimming pools and in open waters such as rivers and seas before the age of 15 years, was associated with odds ratios of 2.20 (95% confidence interval (CI), 1.05-4.62) and 2.41 (95% CI, 1.04-5.58), respectively, compared with no swimming at all or swimming in relatively unpolluted waters, such as lakes and fens. Melanoma patients learned to swim at a younger age; compared with those who never learned to swim or who learned to swim after the age of 12 years, the odds ratio was 1.87 (95% CI, 0.91-3.78) for those who learned to swim at ages 9-12 years, and 2.22 (95% CI, 1.16-4.26) for those who learned to swim before 9 years of age. Compared with persons who had no swimming certificates, an odds ratio of 1.25 (95% CI, 0.71-2.23) was found for persons with one or two certificates, and an odds ratio of 2.96 (95% CI, 1.25-6.96) for persons with three or more certificates. The positive association between a history of swimming and melanoma risk suggests that carcinogenic agents in water, possibly chlorination by products, play a role in melanoma aetiology.

Adolescent↗
PubMed1994

Should random urothelial biopsies be taken from patients with primary superficial bladder cancer? A decision analysis. Members of the Dutch South-East Co-Operative Urological Group.

OBJECTIVE: To evaluate whether it is worthwhile to implement routine random biopsies from the normal-looking urothelium in the management of patients with primary superficial bladder cancer. PATIENTS AND METHODS: Two hypothetical management policies were compared, one of which incorporated random biopsies as an additional prognostic test. In the 'no-biopsy policy', all patients were treated with transurethral resection (TUR) alone, except for patients with a pT1G3 tumour who were treated with adjuvant prophylactic intravesical therapy. In the 'biopsy policy', the choice of treatment was influenced by the presence or absence of dysplastic urothelium in random biopsy specimens, except in patients with a pT1G3 tumour who received adjuvant treatment, irrespective of the result of random biopsies. Decision analysis was used to compare the outcome of these hypothetical policies with respect to the expected 3-year risks of recurrence and progression. Baseline data used in the analysis originated from a large unselected case series, prospectively documented in the Netherlands. RESULTS: The 'biopsy policy' resulted in a 3 year risk of recurrence and a 3 year risk of progression of 52% and 11%, respectively. These 3 year risks were almost identical to the 'no-biopsy policy': 54% and 11%, respectively. In a sensitivity-analysis, the expected 3 year risks of recurrence as well as the expected 3 year risks of progression were found to remain similar with both policies, even with quite extreme assumptions favouring the 'biopsy policy'. CONCLUSION: In view of the expected small difference in disease outcome between the two management policies, taking random biopsies of normal-looking urothelium at the time of the TUR has no practical value.

Adolescent↗
PubMed1994

Smoking and drinking habits in relation to prostate cancer.

OBJECTIVE: To evaluate the role of tobacco and alcohol consumption in the aetiology of prostate cancer. PATIENTS AND METHODS: In a case-control study conducted in the Netherlands, information on smoking and drinking habits was obtained from questionnaires completed by 345 patients exhibiting primary prostate cancer and by 1346 controls with benign prostate hyperplasia. The response rate was 79%. RESULTS: No association was observed between drinking habits and the risk of prostate cancer (324 cases versus 1237 controls; odds ratio 1.36; 95%CI 0.84-2.22). A significantly elevated odds ratio was found for individuals who had smoked at any time during their lives (329 cases versus 1212 controls; odds ratio 2.12; 95%CI 1.24-3.62). However, no relationship was observed between the number of cigarettes smoked, the duration of smoking, the age at which the subjects started smoking or with the calendar period in which they were born. Odds ratios calculated for individuals who smoked in consecutive 5-year periods between 1940 and 1989 did not show any trend. Furthermore, the risk of prostate cancer among ex-smokers did not differ significantly from the risk among current smokers, even when smoking was stopped more than 25 years previously. CONCLUSION: From these findings, which do not point to the causative agent, it would appear that neither smoking nor alcohol consumption seriously increases the risk of prostate cancer.

Age Factors↗
PubMed1994

Cancer incidence: life table risk versus cumulative risk.

STUDY OBJECTIVE: To study differences between various methods of estimating cancer risk in individuals. DESIGN: Information was obtained from a cancer registry. Lifetime risk was calculated using the life table method, taking competing causes of death into account and using well recognised methods such as the cumulative rate and risk. SETTING: Regional cancer registry of the Comprehensive Cancer Centre IKL, located in Maastricht, The Netherlands. PATIENTS: Patients with a first primary malignancy in 1989-90 in the catchment area of the cancer registry. MAIN RESULTS: The lifetime risk of developing cancer was estimated to be 34.8% for males and 30.4% for females. In males, especially, the risk estimates were considerably higher when the cumulative risk was used. CONCLUSIONS: The life table method is convenient for estimating the probability that a person will develop cancer during a defined period or during his or her lifetime. The other estimates overestimate the risk of the disease under investigation, especially in the very elderly.

Adolescent↗
PubMed1994

Diagnosis of hypertrophic pyloric stenosis: value of sonography when used in conjunction with clinical findings and laboratory data.

OBJECTIVE: This study aimed to determine the value of sonography in the diagnosis of hypertrophic pyloric stenosis in patients with no palpable olive-shaped mass. MATERIALS AND METHODS: One hundred and five children with projectile vomiting but no palpable mass had sonography because of possible hypertrophic pyloric stenosis. The patients' history, signs and symptoms, and results of laboratory tests were incorporated into the statistical analysis. Using medical history, signs and symptoms, and laboratory results in one case and history, signs and symptoms, laboratory results, and pyloric measurements based on sonographic findings in another case, we composed the best predicting logistic regression models. RESULTS: The ability to predict hypertrophic pyloric stenosis is greatly increased by adding information obtained from sonography. At 91% specificity of the final model, only 5% of the patients with no evidence of the abnormality actually had hypertrophic pyloric stenosis. The positive predictive value is thus 94%, and the negative predictive value is 95%. CONCLUSION: The results justify the use of sonography as the diagnostic procedure of choice for infants suspected of having hypertrophic pyloric stenosis.

Female↗
PubMed1994

[The value of CT for the diagnosis of rectal cancer recurrence. A ROC study and a retrospective analysis].

To assess the ability of CT to detect recurrent tumor growth after colorectal surgery for rectal carcinoma independently of clinical bias and patient selection, a receiver operator characteristic (ROC) analysis was performed. A set of 100 CT scans, 50 scans of 35 patients with proven recurrent disease, and 50 normal postoperatives of 37 patients were read by four observers without knowledge of the present clinical status. The four ROC curves had an area under the curve (AUC) ranging from 0.69 to 0.78 (SD from 0.046 to 0.053). The slightly raised AUC indicates the poor diagnostic power of CT in discriminating between postoperative changes and recurrence. In a retrospective analysis of the CT scans of the 72 patients CT had an overall accuracy of 83%. CT was unable to detect small anastomotic recurrence. The morphological characteristics of recurrence were not specific, but an irregular globular mass with or without inhomogeneity or asymmetry strongly suggests recurrent tumor and stresses the need for further evaluation, e.g., CT-guided biopsy.

Female↗