Search PubMed⌕ Search

Biomedical subjects

J H Hendriks

Publications and source records attributed to J H Hendriks.

At least 37 records · Page 2Linked to original sources
PubMed1998

Automated detection of breast carcinomas not detected in a screening program.

PURPOSE: To investigate the possibility of automated detection of early signs of cancer that were not detected in a breast cancer screening program. MATERIALS AND METHODS: A set of 75 mammograms (in 65 women) with subtle circumscribed masses, stellate lesions, and architectural distortions that were not detected in a screening program by two radiologists was assembled and extended with 142 normal mammograms (contralateral mammograms in the same 65 women). An automated system for the detection of circumscribed masses and stellate lesions was applied to this set. RESULTS: In 22 (34%) of 65 cases, an early sign of cancer was detected at a specificity of one false-positive finding per image. At a specificity of three false-positive findings per image, 39 (60%) of the cancers were detected. Of the tumors that were classified as screening errors, seven (50%) were found at a specificity of 0.5 false-positive finding per image. CONCLUSION: A substantial proportion of cancers that were missed in a screening program, despite double reading, were found with this detection method at less than one false-positive finding per image.

Algorithms↗
PubMed1997

Breast-cancer mortality in a non-randomized trial on mammographic screening in women over age 65.

Recent case-referent studies in the Nijmegen breast-screening programme have shown a reduction in breast-cancer mortality of approximately 50% due to screening of women aged 65 years and older. In this type of study, however, the results may be biased because of self-selection. The purpose of our present study was to compare the breast-cancer mortality rate in a population invited for screening with that of a reference population from an area without a screening programme. In 1977-1978, 6773 women aged 68-83 years were enrolled in the mammographic screening programme in Nijmegen, The Netherlands. The women were followed up until 31 December, 1990. The reference population consisted of women from the same birth cohort from Arnhem, a neighbouring city without mass screening, for whom the entry date was 1 January, 1978. The ratios of the Nijmegen and Arnhem breast-cancer mortality rates with 95% confidence intervals (CI) were calculated. In the study period, 173 patients were diagnosed with primary breast cancer in Nijmegen vs. 183 in Arnhem; 40 Nijmegen patients had died of breast cancer vs. 51 Arnhem patients. The cumulative mortality-rate ratio was 0.80 (95% CI = 0.53-1.22). In the periods 1978-1981, 1982-1985 and 1986-1990, the mortality rate ratios were 1.44 (95% CI = 0.67-3.10), 081 (95% CI = 0.37-1.79) and 0.53 (95% CI = 0.27-1.04), respectively. After adjustment for the difference in incidence rate that existed between the Nijmegen and Arnhem populations, mammographic screening of women older than 65 can be expected to yield a 40% reduction in breast-cancer mortality after 10 years.

Aged↗
PubMed1997

Computer-assisted reading of mammograms.

Techniques developed in computer vision and automated pattern recognition can be applied to assist radiologists in reading mammograms. With the introduction of direct digital mammography this will become a feasible approach. A radiologist in breast cancer screening can use findings of the computer as a second opinion, or as a pointer to suspicious regions. This may increase the sensitivity and specificity of screening programs, and it may avoid the need for double reading. In this paper methods which have been developed for automated detection of mammographic abnormalities are reviewed. Programs for detecting microcalcification clusters and stellate lesions have reached a level of performance which makes application in practice viable. Current programs for recognition of masses and asymmetry perform less well. Large-scale studies still have to demonstrate if radiologists in a screening situation can deal with the relatively large number of false positives which are marked by computer programs, where the number of normal cases is much higher than in observer experiments conducted thus far.

Breast Neoplasms↗
PubMed1997

Mammographic changes in postmenopausal women on hormonal replacement therapy.

The purpose of this study was to investigate the extent of the effects of hormonal replacement therapy (HRT) on the mammographic breast pattern in postmenopausal women. In a hospital-based study mammographic examinations of 81 postmenopausal women were evaluated retrospectively, before and after 1-2 years of treatment with oestrogens or a combination of oestrogens and progestagens. Each individual mammographic film was examined separately, and the glandular tissue was classified according to a modified Wolfe classification. In a screening-centre-based study two consecutive mammograms, with a 2-year interval, of 645 women, of whom 70 were using some kind of hormone therapy, were evaluated retrospectively. In the hospital-based study 31 % of patients treated with combination HRT showed an increase in fibroglandular tissue compared with only 8.7 % in the group treated with oestrogens alone. The difference was statistically significant (p = 0.046). In the screening-based study 14.3 % of the women using hormonal therapy showed an increase, whereas in the non-users no increase was found (p = 1.24 x 10(-10)). After beginning HRT many women (between 14 and 25 % in our experience) can be expected to undergo a mammographically detectable increase in fibroglandular tissue. Radiologists should be aware of the aetiology of such changes, and can obtain information on HRT most conveniently by having the technologist routinely question each patient.

Aged↗
PubMed1997

Do non-specific minimal signs in a biennial mammographic breast cancer screening programme need further diagnostic assessment?

Mammographic features such as small vague densities, indefinable microcalcifications, subtle architectural distortions, alone or in combination, are non-specific appearances for breast cancer. These features sometimes precede malignancy and a decisive strategy on how to deal with non-specific minimal signs in a breast cancer screening programme is therefore desirable. After studying the prevalence of these signs in a Dutch Breast Cancer Screening Centre and estimating the risk of participants with these signs acquiring breast cancer within 2 years, we have developed such a strategy. Non-specific minimal signs were seen on the mammograms of 53 of 500 (10.6%) participants, aged 50-70 years, in this programme. After retrospective analysis of the mammograms of 254 patients with screen-detected or interval carcinoma, non-specific minimal signs were detected in 77 cases. Combining the incidence of breast cancer with the difference between the expected number of non-specific minimal signs in the screening programme and its actual occurrence in previous mammograms of patients with breast cancer, the risk of cancer in women with these signs, additional to that of screened women in general (additional risk), is calculated as being 0.5%. Invasive breast cancer in women with previously detected non-specific minimal signs demonstrated a favourable stage at diagnosis (axillary metastasis in 23% vs 37% in cancers without these previous signs, p < or = 0.05). Our strategy for follow-up in case of non-specific minimal signs remains unchanged because of the low additional risk and favourable staging, and is restricted to an invitation for the next screening round in 2 years time.

Aged↗
PubMed1996

Personality factors and breast cancer development: a prospective longitudinal study.

BACKGROUND: It has been estimated that approximately 25% of all breast cancers in women can be explained by currently recognized somatic (i.e., hereditary and physiologic) risk factors. It has also been hypothesized that psychological factors may play a role in the development of breast cancer. PURPOSE: We investigated the extent to which personality factors, in addition to somatic risk factors, may be associated with the development of primary breast cancer. METHODS: We employed a prospective, longitudinal study design. From 1989 through 1990, a personality questionnaire was sent to all female residents of the Dutch city of Nijmegen who were 43 years of age or older. This questionnaire was sent as part of an invitation to participate in a population-based breast cancer screening program. Women who developed breast cancer among those who returned completed questionnaires were compared with women without such a diagnosis in regard to somatic risk factors and personality traits, including anxiety, anger, depression, rationality, anti-emotionality (i.e., an absence of emotional behavior or a lack of trust in one's own feelings), understanding, optimism, social support, and the expression and control of emotions. Conditional logistic regression analysis was used to identify variables that could best explain group membership (i.e., belonging to the case [breast cancer] or the control [without disease] group). RESULTS: Personality questionnaires were sent to 28 940 women, and 9705 (34%) were returned in such a way that they could be used for statistical analyses. Among the 9705 women who returned useable questionnaires, 131 were diagnosed with breast cancer during the period from 1989 through 1994. Seven hundred seventy-one age-matched control subjects (up to six per case patient) were selected for the analyses. Three variables were found to be statistically significantly associated with an increased risk of breast cancer: 1) having a first-degree family member with breast cancer (versus not having an affected first-degree relative, odds ratio [OR] = 4.05; 95% confidence interval [CI] = 1.76-9.31); 2) nulliparity (i.e., having no children) (versus having had a child before the age of 30 years, OR = 2.67; 95% CI = 1.26-5.68); and 3) a relatively high score on the personality scale of anti-emotionality (versus a low score, OR = 1.19; 95% CI = 1.05-1.35). CONCLUSIONS AND IMPLICATIONS: With the exception of a weak association between a high score on the anti-emotionality scale and the development of breast cancer, no support was found for the hypothesis that personality traits can differentiate between groups of women with and without breast cancer. We recommend that this study be continued and that other studies be encouraged to explore possible relationships between personality factors and the risk of breast cancer.

Adult↗
PubMed1996

Mammographic screening after the age of 65 years: evidence for a reduction in breast cancer mortality.

We evaluated whether regular mammographic screening of women aged 65 years or older affected breast cancer mortality. In Nijmegen, a population-based screening program for breast cancer was started in 1975, with biennial mammography for women aged 35-64 years. Since 1977, elderly women have also been participating. For the present case-control study, women were selected who were over 64 years of age at the most recent invitation. Eighty-two of them had died from breast cancer. For these cases, 410 age-matched population controls were selected. The ratio of breast cancer mortality rates of the women who had participated regularly (ie., in the 2 most recent screening rounds prior to diagnosis) vs. the women who had not participated in the screening was 0.56 (95% CI = 0.28-1.13). The rate ratio was 0.45 in the women aged 65-74 years at the most recent invitation (95% CI = 0.20-1.02), whereas it was 1.05 in the women aged 75 years and older (95% CI = 0.27- 4.14). While the breast cancer survival rate of the non-participant patients was fairly equal to that of patients from a control population, the underlying incidence rate of breast cancer was higher in the participants than in the non-participants. Therefore, we conclude that bias was present, but that it had decreased our effect estimate. The real reduction in breast cancer mortality due to regular screening will be even larger. Regular mammographic screening of women over age 65 (at least up to 75 years) can reduce breast cancer mortality by approximately 45%.

Aged↗
PubMed1996

Children on hunger strike: child abuse or legitimate protest?

The issue of children on hunger strike (voluntary total fasting) has not been reported before. The World Medical Association Declaration of Tokyo 1975 and the Declaration of Malta 1991 (revised 1992) provide clinicians with guidelines for the management of adult patients on hunger strike but do not mention children. We report the management of 14 Vietnamese children, aged 1 to 12 years, who took part in a hunger strike at a refugee detention centre in Hong Kong.

Child↗
PubMed1996

Age-specific sensitivities of mammographic screening for breast cancer.

The sensitivity of the mammographic screening test in the biennial screening program of Nijmegen is assessed by analyzing the occurrence of interval cancers, i.e. cancers surfacing clinically in the interval between a negative screening examination and the subsequent scheduled examination. The difference between the observed number of interval cancers and the expected number of clinically manifest cancers in the absence of screening for the interval period reflects the number of cancers detected by screening. The expected number should be limited by the number of those cancers that were not detectable at the time of the screening examination because their size was under the threshold of mammographic detectability (5 mm). In contrast to other sensitivity studies we took these 'fast growing' cancers into consideration, the numbers of which are estimated in each of the six-month periods of the two-year interval using age-specific tumor volume growth rates for three age groups: < 50, 50-69, and > or = 70 years. In patients under age 50, the sensitivity was 64% for cancers which would become clinically manifest within one year after screening. This sensitivity was lower than those obtained from the 50-69 and > or = 70 age groups, being 85% and 80%, respectively. For cancers that would become clinically manifest 12-18 months after screening, sensitivity decreases to 22% in the under age 50 group, and to 56% and 65% in the two above age 50 groups, respectively. We conclude that even when adjusted for growth rate, the mammographic screening test has a poor performance in the under age 50 group.

Adult↗
PubMed1996

Prognosis of younger and older patients with early breast cancer.

The use of mammography in recent years has resulted in an increase in the detection of small breast cancers. The beneficial effects of early detection on breast cancer mortality seem to differ with age. To obtain more insight into this matter we studied the long-term prognosis of patients with early invasive breast cancers (T1) in three age groups: 144 patients of age 40-49, 402 patients of age 50-69 and 192 patients 70 years or older at diagnosis. In all age groups, patients with a tumour of 1 cm or less have a longer breast cancer specific survival than patients with a tumour larger than 2 cm. The survival advantage in the case of tumours of a size rounded to 1.5 cm compared with tumours larger than 2 cm in the under age 50 group was marginal (and not significant). However, older patients with tumours of this size do have a significantly improved survival. It is more difficult to improve survival in younger patients through early detection, partly because of an apparent early metastatic potential of their tumours. A reduction in breast cancer mortality might be expected in women younger than 50 years of age only if a substantial proportion of the invasive cancers are detected before their size exceeds 1 cm.

Adult↗
PubMed1996

Long term breast cancer screening in Nijmegen, The Netherlands: the nine rounds from 1975-92.

STUDY OBJECTIVE: To assess the performance of breast cancer screening in different age categories over two decades. DESIGN: Important determinants of reduced breast cancer mortality such as attendance, mammography performance, cancer detection, and disease stage were recorded. SETTING: Nijmegen, The Netherlands, 1975-92. SUBJECTS: Since 1975 more than 40,000 women aged 35 years and older have been invited biennially for breast screening in a population based project in Nijmegen. MAIN RESULTS: Rates of attendance, referral, detection, and disease stage were calculated, as well as the specificity of screening mammography and the predictive value of referral and biopsy. From round 3 onwards, the attendance rate of women younger than 50 years stabilised at 70%, in women of 50-69 years it was 62%, and in women aged 70 and over it was 22%. In these three age categories, the referral rates of a positive screening mammography per 1000 screened women were 4.9, 6.2, and 11.8, respectively. Specificity rates were between 99% and 100%. Current predictive values of referral were high: in the specific age categories 39%, 59%, and 68% of the referred women had cancer. Detection rates remained fairly stable over the rounds 4-9, at 1.9, 3.6, and 8.0 cancers per 1000 screened women. In the two year period between screening the numbers of interval cancers per 1000 screened women were 2.2, 2.2, and 2.9, for the three age categories respectively. With regard to invasive cancers detected during screening, the percentage of small tumours (< or = 20 mm on the mammogram) was 84% in each age category. For women younger than 50 years, the proportion of intraductal carcinoma in all the cancers detected at screening was 40%, while it was 15% in the other age categories. CONCLUSION: Throughout the nine rounds, the screening outcomes were found to be adequate, particularly considering the high specificity rate and the predictive value of referral without the interference of a low detection rate. Although the occurrence of interval cancers seemed high, it was similar to other screening programmes. Despite a relatively low referral rate, the ratios of screen detected versus interval cancer cases were favourable. Well organised screening programmes can achieve good mammography results without too many false positives. It is important that women continue to participate in a screening programme because cancer can still be detected even after several successive negative screening examinations.

Adult↗
PubMed1995

Nation-wide breast cancer screening in The Netherlands: support for breast-cancer mortality reduction. National Evaluation Team for Breast Cancer Screening (NETB).

The nation-wide 2-yearly breast-cancer screening programme in The Netherlands, for women aged 50-69, started around 1988, and was predicted to result eventually in a 16% reduction in breast-cancer mortality in the total female population. We present the results of screening up to January 1, 1993, and compare these with the predicted results from the cost-effectiveness analysis, on which basis this mortality reduction has been calculated. At least 550,000 women aged 50-69 were invited to screening in 1990-1992, and 75% of these participated. Cancer was suspected from 5,162 examinations and further investigation was therefore required. Excision biopsy was done in 72% of referrals, and 2,515 breast cancers were detected. The results for 404,000 newly invited women compare favourably with expected values (in parentheses): 78% attendance rate (70%), 1.4% screen positive (1.6%), 6.8 cancers detected per 1,000 women screened (6.4) and 38% of these cancers were DCIS or invasive carcinomas smaller than 11 mm in diameter (36%). More data, e.g., on treatment and interval cancers, will follow in the years to come. These first results can be interpreted as strong early signs of a reduction in breast-cancer mortality of at least the predicted size. Screening has sufficiently advanced the diagnosis, as well as or better than expected. Breast cancers diagnosed in this age group without screening are diagnosed at a worse stage than expected. Unfavourable side-effects, especially false-positive referrals, might be kept lower than those reported in other countries.

Aged↗
PubMed1995

Effect on breast cancer mortality of biennial mammographic screening of women under age 50.

The effects on breast cancer mortality seen after 16 years of biennial screening of younger women are assessed in this prospective cohort study. Since 1975 some 13,500 women, aged 35-49 in 1975, were invited to participate in the Nijmegen screening programme comprising a mammographic examination every 2 years. By the end of 1990, 75 women had died of breast cancer out of the 332 cases diagnosed after the start of the screening project. Women from the same birth cohort, living in Arnhem, a neighbouring city with a comparable population and without a screening project, were used as controls. In this city, 74 breast cancer deaths out of 284 cases occurred during the same period. In Nijmegen, after 16 years of follow-up, breast cancer mortality showed a non-significant reduction of 6% (95% confidence interval: 32% reduction, 29% excess). In the relevant period, after a time lag of 10 years from the start of the programme, this reduction rose to 20% (95% confidence interval: 48% reduction, 23% excess). No reduction in breast cancer mortality was observed in the first decade of screening. For a later period, a shift towards a reduction emerges, but the data are as yet inconclusive.

Adult↗
PubMed1995

Breast tumors: comparative accuracy of MR imaging relative to mammography and US for demonstrating extent.

PURPOSE: To evaluate the comparative accuracy of magnetic resonance (MR) imaging relative to mammography and ultrasonography (US) for assessing the extent of breast tumors. MATERIALS AND METHODS: Histologic results and preoperative imaging findings (mammography, US, MR imaging) were analyzed regarding tumor size and multifocality of 61 tumors in 60 women undergoing mastectomy for carcinoma. RESULTS: In 10% of cases, the index tumor was not seen at mammography. With US, 15% of the index tumors were not recognized, while MR imaging missed 2% of the index tumors. On mammographic and US images, tumor size was underestimated significantly (P < .005), by 14% and 18%, respectively, while MR imaging showed no significant difference in size compared with that found in a pathologic evaluation. Mammography showed 31% of the additional invasive lesions, while US showed 38% and MR imaging showed 100%. CONCLUSION: MR imaging was the most accurate of the three preoperative imaging modalities in assessing the size and number of malignant lesions in the breast.

Adult↗
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↗
PubMed1995

Personality traits of women with breast cancer: before and after diagnosis.

The aim of this study was to investigate the extent to which the diagnosis of breast cancer influences the self-assessment of personality traits by patients. In 1989 and 1990, all female inhabitants of Nijmegen aged 43 years and over were invited to participate in a population screening for breast cancer and were asked to complete a personality questionnaire. During 1989-1992, 25 women who were diagnosed as having breast cancer were psychologically assessed for a second time 1 1/2 years after diagnosis. A control group of 822 healthy women also completed the questionnaire twice. A statistically significant decrease in scores on three scales (Rationality, Emotional Expression-out, and Emotional-Control) was reported by the patient group compared to the control group.

Adult↗