Cervical cytology screening in Vietnamese asylum seekers in a Hong Kong detention center. Population demographics and historical perspectives

OBJECTIVE: To provide a brief review of the history and demographics of the Vietnamese asylum-seeking population in Hong Kong and their possible effects on the initiation of a cervical cytology screening program at a Hong Kong detention center. STUDY DESIGN: Analysis of case histories, questionnaires and interviews with women in a detention center identified demographic features related to Pap smear history, knowledge of the Pap test, age at first intercourse and cigarette smoking status among women aged 17 years and over. Analysis of Pap smear uptake following initiation of a screening program was undertaken. RESULTS: Of the 1,171 women in the detention center who were eligible for a Pap smear, 536 (45.8%) actually obtained one, although enrollment, which was strong at the initial offering, slowed considerably as the program progressed. None of the women had had a Pap smear prior to leaving Vietnam. Knowledge of the utility and risk status criteria for Pap testing was very limited. The majority (77.9%) of the subjects started sexual activity after age 20 years, and three (0.6%) smoked. There were four (0.2%) abnormal smears identified among those tested. CONCLUSION: Convincing evidence was obtained that the Pap test was not widely used in Vietnam among the asylum-seeking population, and its role in preventing cervical cancer was not well known to the women studied. The initial strong uptake of the Pap smear was not maintained. That may be attributable to psychosocial factors associated with detention under harsh conditions and trauma associated with fleeing Vietnam.     

Cervical cancers diagnosed after negative results on cervical cytology: perspective in the 1980s.

OBJECTIVES--To assess the magnitude of the problem of interval cancers of the cervix (those that are diagnosed within a short time after negative screening test results) in the 1980s, to compare the nature of interval cancers in younger women with that in older women, and, by reviewing negative cervical smears, to determine the proportion of interval cancers that might represent the development of malignancy anew compared with the proportion that might be associated with difficulties in sampling or errors in reporting. DESIGN--An audit of the interval cases of cervical cancer that had been diagnosed within 36 months of a smear having been reported as negative by the Victorian Cytology Gynaecological Service among women registered with cervical cancer during 1982-6. SETTING--The Victorian Cytology Gynaecological Service, a free public sector cytology laboratory in Victoria, Australia. SUBJECTS--138 Women, all of whom had had cervical cancer diagnosed during the 36 months after having had a negative cervical smear. Subjects were divided into two age groups: younger women, aged less than 35; older women, aged 35-69. INTERVENTIONS--Negative slides were reviewed for evidence of optimal sampling and for the presence of cellular abnormalities that had been missed at the time of the original reporting. MAIN OUTCOME MEASURES--The number of interval cases of cancer of the cervix registered during 1982-6. The proportion of interval cases occurring in younger women and the proportion occurring in older women. Division of women into three risk categories based on clinical history and screening history that broadly corresponded to the probability that a diagnosis of cervical cancer might be expected during the 36 months after the issuing of a negative smear report. RESULTS--138 Of 1044 (13.2%) women who had been registered with cervical cancer during 1982-6 had had one or more negative smears during the 36 months preceding the diagnosis of cancer. Interval cancers comprised a larger proportion of registrations of cervical cancer in women aged less than 35 years than in women aged 35-69 (21.1% v 11.0%, p less than 0.01). Women with interval cancer who had had at least three negative smears during the 10 years before the diagnosis of cancer were commoner in the younger age group than in the older age group (7.0% v 2.5%, p less than 0.01). When, however, the number of observed cases of squamous cell carcinoma was related to the number of expected cases in the absence of screening, no significant difference was found between the two age groups (6.8% v 4.8%, p greater than 0.10). The rate of diagnosis of interval cancer per 100,000 negative tests was lower among younger women than among older women (10/100,000 v 16/100,000). Review of the negative slides showed that 11.9% were again considered to be negative with an optimal sample having been obtained as evidenced by the presence of endocervical cells or metaplastic cells, or both. CONCLUSIONS--Interval cancers might comprise a larger proportion of all registered cases of cervical cancer among younger women owing to the larger proportion of such cancers being prevented in this age group. Among women with interval cancer review of the negative slides showed that most were accounted for by suboptimal sampling or by errors of reporting.     

A case-control study of cervical cancer screening in north east Scotland.

To estimate the relative risk of invasive cervical cancer in each succeeding year after a negative screening result the screening records of all women tested in the north east of Scotland were examined as the basis for a case-control study. The cases consisted of 115 women in whom invasive cervical cancer had been diagnosed in 1968-82 and who had appeared in the screening records at least once before diagnosis. For each patient five controls were selected from women of the same age who appeared in the screening records before the date of diagnosis in the patient. If the patient''s cancer had been detected by screening the controls were chosen from women of the same age screened the same year. A comparison was made between cases and controls of the number of negative smears taken before the diagnosis. The results showed a high relative protection (inverse of the relative risk) in the first two years after a negative test, falling steadily as time since the last negative test elapsed. Even after 10 years, however, a considerable residual effect was observed.     

Detecting hypertension: screening versus case finding in Norway.

OBJECTIVE--Evaluation of detection of hypertension in adults in the county of Nord-Trøndelag, Norway. DESIGN--Cross sectional survey with clinical follow up examinations. SETTING--Health survey by screening teams from the national health screening service, and examinations by all 106 general practitioners in the county. SUBJECTS--During 1984-6, 74,977 persons (88.1% of those aged 20 years and over) participated in the health survey. MAIN OUTCOME MEASURES--Hypertension (when assessed by standardised recording and by questionnaires on drug treatment for hypertension) according to the blood pressure thresholds used in the Norwegian treatment programme. Subjects positive on screening were grouped after clinical examination into treatment groups. RESULTS--In all, 2399 subjects were positive for hypertension. Before screening 6210 (8.3%) patients reported taking antihypertensive drugs and another 3849 (5.1%) had their blood pressure monitored regularly. All who screened positive were referred to their general practitioner and evaluated according to a standard programme. As a result, drug treatment was started in 406 (0.5%) participants screened and blood pressure monitoring in another 1007 (1.3%). Of all patients taking antihypertensive drugs after the screening, 6399 (94.0%) had been diagnosed before screening, and of those whose blood pressure was monitored after the screening, 79.3% had been diagnosed before screening. CONCLUSIONS--At the blood pressure screening thresholds used, and when hypertension is defined by an overall clinical diagnosis, the results indicate that general practitioners can find and diagnose hypertensive patients with the case finding strategy.     

Cervical cancer screening programs: summary of the 1982. Canadian task force report.

The Canadian Task Force on Cervical Cancer Screening Programs, which produced its first report in 1976, was reconvened by the Department of National Health and Welfare in 1980 in response to concerns expressed about the significance of new data, changing sociosexual patterns and wide variations in the implementation of the 1976 recommendations. This article is a summary of the 1982 task force report. In addition to updates of the 1976 material new sections appear on groups at risk, mathematical models of screening, quality control in screening programs, cytologic screening coverage of the Canadian population and management of patients with abnormal smears. The 1982 recommendations deal with frequency of screening, laboratory quality control and follow-up mechanisms. The task force concludes that measures to improve the quality and sensitivity of screening programs and to include women who have never been screened will be more effective in reducing mortality from carcinoma of the cervix than will attempts to increase the frequency of screening. The task force views as unnecessary the annual screening of women over 35 years of age whose previous smears have been normal. Since younger women are sexually more active and tend to have more than one sexual partner they are at high risk. Therefore, the task force recommends annual screening for sexually active women aged 18 to 35 years. Physicians, health care professionals and government health agencies have a role to play in informing women about the recommended intervals for cervical smears and ensuring that screening programs of adequate quality are available. Although women are primarily responsible for entering and continuing in such a program, government-sponsored registries are essential if the full potential of cervical smear programs is to be realized.     

Rationale for stopping cervical screening in women over 50.

OBJECTIVE--To investigate whether the currently recommended age at which to stop cervical screening (64) can be lowered and what criteria should be used for safely doing so. DESIGN--Retrospective case analysis study. SETTING--Dundee and Angus districts of Scotland. SUBJECTS--Women diagnosed as having cervical intraepithelial neoplasia and microinvasive or invasive cancer of the cervix in 1989 and 1990 (798 cases). MAIN OUTCOME MEASURE--History of cervical cytology results according to age (age groups of five years) and screening interval (three years and five years). RESULTS--Cervical intraepithelial neoplasia was most common in women under 45 (711 cases in women of 45 and under v 38 cases in those of 46 and over). Cervical intraepithelial neoplasia occurring de novo was not seen in women over 50 who had been screened every three years. Microinvasive or invasive cancer of the cervix was diagnosed in 26 women over 50. None of these women had participated adequately in the cervical screening programme. CONCLUSION--Cervical intraepithelial neoplasia typically occurs in younger women. All women over 50 with an adequate history of negative results on smear testing every three years may be safely discharged from further screening if these findings are confirmed in other populations.     

Impact of the Walton report on cervical cancer screening programs in Canada.

It is almost 4 years since the Walton report on cervical cancer screening programs was published. In an effort to assess the impact of this report on such programs across Canada the Department of National Health and Welfare carried out a survey using questionnaires. It appears from the evaluation that physicians, laboratories and provincial departments of health are giving thoughtful but cautious consideration to implementing the report''s recommendations. Stated areas of controversy include the recommended frequency of cervical smear examination, the establishment of province-wide cytology registries and the recommended size of laboratories. Perhaps the pace will quicken as additional knowledge and experience are gained. Perhaps, too, if a national mechanism to encourage provincial implementation were instituted hesitancy would decrease.     

Screening for squamous cervical cancer: duration of low risk after negative results of cervical cytology and its implication for screening policies. IARC Working Group on evaluation of cervical cancer screening programmes.

A collaborative study of screening programmes in eight countries was performed to estimate the risks of cervical cancer associated with different screening policies. Most of the data came from centrally organised screening programmes. Relative protection was higher in women who had had two or more negative results of screening tests than in those who had had only one negative smear, particularly in the first five years after the last test. There was little difference in the protection afforded by screening every year compared with every three years, but screening only once every five or 10 years offered appreciably less protection. The age of the women did not affect the sensitivity of the test or the sojourn time of the disease (the length of the detectable preclinical phase during which abnormal cytology could be picked up if a smear were taken); invasive cancer in women under 25 was rare. Centrally organised screening programmes were more effective than uncoordinated screening. Screening programmes should be aimed principally at women aged 35-60 but should start some years before the age of 35, and the intervals between screening should be three years or less.     

Cervical cancer screening in Middle Eastern and Asian migrants to Australia: A record linkage study

Background. Australia's organized cervical screening program recommends two-yearly screening for women aged 18–69 years and reminder letters are sent at 27 months. Cervical screening registers hold comprehensive information on screening, but not country of birth. A linkage study was performed in order to assess cervical screening behavior in migrants. Methods. To assess screening participation, we linked year 2000 records for 12,541 Middle Eastern/Asian-born women 20–54 years of age, and an age and area matched random sample of 12,143 Australian-born women in the New South Wales (NSW) Midwives Data Collection (MDC), which records country of birth, to screening register records. Screening behavior after 2000 was assessed in women without a recorded prior cervical abnormality. Results. The odds ratios for being screened at least once within a 3 year period, with reference to Australian-born women and adjusted for age, parity, socioeconomic status and smoking, were 0.88 (95% CI: 0.81–0.97) and 0.74 (95% CI: 0.70–0.79) in women born in the Middle East and Asia, respectively. Screening increased with increasing socioeconomic status (SES), absence of smoking and greater parity in Australian-born women but little, if at all, in migrant women. In a sensitivity analysis in which hospital admitted patients were the source of population samples, some patterns were sufficiently different to suggest that selection for illness can affect the strength and direction of associations in linked data. Conclusion. Migrant women from Asian and Middle-eastern countries are less likely than Australian-born women to participate in cervical screening at the recommended interval. Their likelihood of screening is also less related to socioeconomic status, smoking and parity than that in Australian-born women.     

Quinquennial cervical smears: every woman's right and every general practitioner's responsibility.

Out of 558 women aged 16 to 64 who were registered with one general practitioner, 459 were eligible to be screened for cervical cancer. Even though the practice had been taking cervical smears for many years, they were predominantly from women under 35. Of the eligible women between 35 and 64, 111 (37%) had never had a smear. After short term intensive screening the uptake rates, defined by a smear done within the past five years, rose to 100% for women under 35, 94% for those aged 35 to 64, and 96% for all eligible women. Screening was rewarding both in its clinical yield and in the income generated by item of service payment. The success of screening was largely due to the participation of practice nurses in taking smears, and to a new method of recording smear results and claims for them. Some women, however, refused to have cervical smears.     

Criteria for organized cervical screening programs. Special emphasis on The Netherlands program

Based on the criteria of Wilson and Jungner and experiences in the population-based organized cervical screening program in the Netherlands, conditions for efficient and effective population screening for cervical cancer are described. The purpose of this paper is to determine if these criteria are met for cervical cancer screening and to give recommendations for improvement. Cervical cancer is still an important health problem; the present incidence reflects both background risk and screening activity during previous decades. A positive effect of screening is reached because of the long development time of the disease and the ability of the Pap smear test to detect precancer and early, symptomatic disease. Considerable reduction in the incidence and mortality of cervical cancers can be reached if all women attend and all detected lesions are adequately followed up. Common terminology and classification criteria for histology and cytology should be used. Whether newly developed techniques that may improve or replace cytology can be used in screening programs should be a multidisciplinary decision after clinical trials have given evidence-based information on the performance, cost-effectiveness and need of these techniques. When cervical cancer screening is undertaken, it should be offered in organized programs at the medical level closest to the patients, the general practitioner. High compliance is the most important factor in reducing cervical cancer incidence. Quality control and assurance must be performed at all levels. In the case of limited resources, the program should use a five-year interval and concentrate on the age range 25-60 years, with special attention to women who have never been screened or were screened > 10 years previously. Evaluation of medical and organizational aspects is mandatory. Cooperation between all involved parties is a prerequisite of creating a successful screening program.     

Organisation and results of the cervical cytology screening programme in British Columbia, 1955-85

A screening programme to detect preinvasive carcinoma of the cervix was started in British Columbia in 1949. Since 1970 the number of women who have been screened at least once has been maintained at about 85% of the population at risk. More than 500 000 cervical smears are being examined each year in the central laboratory. There has been an appreciable increase in the number of cases and rates of carcinoma in situ seen since 1970, particularly in women between 20 and 30 years of age. Since the programme started over 26 000 cases of squamous carcinoma in situ have been detected and treated. The incidence of clinically invasive squamous carcinoma of the cervix has fallen by 78% during the period under review, and mortality from squamous carcinoma of the cervix has fallen by 72%. A colposcopy programme, introduced throughout British Columbia over the past 12 years, has been important in reducing the problems of managing preinvasive lesions, particularly in younger women.It is concluded that the reduction in morbidity and mortality from invasive squamous cancer of the cervix in British Columbia over the past 30 years is directly attributable to the province wide screening programme and that a large potential increase in invasive cervical cancer rates among younger women is being prevented.     

The validation of cervical cytology. Sensitivity, specificity and predictive values

Statistics and methods for the validation of the results of cytologic screening for cervical cancer and its precursors were examined. Many of the methods commonly used, including the calculation of sensitivity and specificity on raw data, contain flaws that undermine their conclusions. Using a large computerized database of 748,871 cytologic screenings of 277,842 women over a ten-year period, the value of screening was examined. Only subsequent histologic examinations within one year were accepted to validate positive initial cytologic diagnoses; only two subsequent cytologic screenings within the next three years were accepted to validate negative initial cytologic diagnoses that had not been followed by a histologic examination. Cases not meeting these criteria were excluded from the initial analysis. From these data, the predictive value of a negative cytologic examination was determined to be 99.8%; the predictive value of a positive cytologic examination was 73.4% for an initial diagnosis of mild-to-moderate dysplasia, 90.6% for a diagnosis of severe dysplasia/carcinoma in situ, 94.5% for a diagnosis of carcinoma in situ or microinvasive carcinoma and 95.5% for an initial diagnosis of invasive carcinoma. Cases with an initial "questionable" cytologic diagnosis had a positive predictive value of only 64.0%. Extrapolation from the validated cases to the entire screened population showed an overall sensitivity of 80% and a specificity of 99.4% for cytologic screening for cervical cancer. The sensitivity was slightly lower for mild and moderate dysplasia (78.1%) and slightly higher for carcinoma in situ and severe dysplasia (81.4%) and invasive carcinoma (82.3%).     

Thyroid cancer after diagnostic administration of iodine-131 in childhood.

Hahn, K., Schnell-Inderst, P., Grosche, B. and Holm, L-E. Thyroid Cancer after Diagnostic Administration of Iodine-131 in Childhood. Radiat. Res. 156, 61-70 (2001).To determine the carcinogenic effects of diagnostic amounts of (131)I on the juvenile thyroid gland, a multicenter retrospective cohort study was conducted on 4,973 subjects who either had been referred for diagnostic tests using uptake of (131)I (n = 2,262) or had had a diagnostic procedure on the thyroid without (131)I (n = 2,711) before the age of 18 years. Follow-up examinations were conducted after a mean period of 20 years after the first examination in 35% of the exposed subjects (n = 789) and in 41% of the nonexposed subjects (n = 1,118). Iodine-131 dosimetry of the thyroid was carried out according to ICRP Report No 53, and the median thyroid dose was 1.0 Gy. In the exposed group, two thyroid cancers were found during 16,500 person-years, compared to three cancers in the nonexposed group during 21,000 person-years. The relative risk for the exposed group was 0.86 (95% CI: 0.14-5.13). The study did not demonstrate an increased risk for thyroid cancer after administration of (131)I in childhood.     

Cervical cancer screening: A Slovenian experience

In Slovenia, opportunistic screening was introduced in regular gynaecological practice in 1960. The proportion of population screened was unknown, as well as there were no standards for quality assurance and control. Despite great number of smears read, there were no major changes in invasive cervical cancer incidence in the period 1979 till 1993, but in 1994 the incidence rate started to increase again to reach its peak in 1997 (23,1/100.000, 241 new cases). Based on the experiences from the countries with effectively organised screening programmes, a decision was made in 1996 by the Minister of Health to nominate a group of experts to prepare a proposal for organised cervical cancer screening programme after testing the methodology in pilot study. In the pilot the central computerised information system (Screening Registry) was gradually established to register all smears from the whole country, to identify women who do not attend for screening to send them invitation for screening and to monitor screening activity and its quality. The aim of pilot was also to develop guidelines for quality assurance and control of all procedures involved in cervical cancer screening and treatment of intraepithelial lesions. In three years since the beginning of the national programme, nearly 70% of women in the target age group were registered with at least one smear. All other results are presented in regular programme reports. There is still place for further development of the programme, but the incidence of cervical cancer already started to decline especially among younger women, who attend for screening more often than those aged over 50.     

CIN 2/3 and cervical cancer after an ASCUS pap smear. A 7-year, prospective study of the Norwegian population-based, coordinated screening program

OBJECTIVE: To estimate the risk of being diagnosed with cervical intraepithelial neoplasia (CIN) 2/3 or invasive cervical cancer (ICC) based on diagnostic and screening procedures performed after a diagnosis of atypical squamous cells of undetermined significance (ASCUS) and to compare this risk to that in women with a normal Pap smears. STUDY DESIGN: A 7-year, prospective, cohort study was performed in the Norwegian population-based, coordinated screening program. After excluding women in the midst of follow-up of an abnormal Pap smear or with a history of CIN 2/3 or ICC, the study population consisted of women 25-69 years of age with a normal (n = 526,661) or ASCUS Pap smear (n = 10,037) in 1995-1996. Risk estimates were calculated by logistic and parametric survival regression. RESULTS: Within 7 years of an ASCUS smear, 1,017 women (10.1%) were diagnosed with CIN 2/3 and 62 (0.62%) with ICC. Women with an ASCUS index Pap smear had a relative risk of 15-30 of being diagnosed with histologically verified CIN 2/3 or ICC within the first 2 years of follow-up as compared to women with a normal index smear. In long-term follow-up, women with an ASCUS index smear followed by a normal smear, which cancelled further clinical follow-up, were at > 3.5 times higher risk of both CIN 2/3 and invasive cancer as compared to women with a normal index smear. CONCLUSION: Pap smear follow-up of women with an ASCUS smear does not identify all women at higher risk of CIN 2/3 and ICC. Other diagnostic procedures should be implemented to improve the screening program.     

Cervical cancer: cytological cervical screening in Iceland and implications of HPV vaccines

K. Sigurdsson
Cervical cancer: cytological cervical screening in Iceland and implications of HPV vaccines This paper reviews the Icelandic experience regarding the age‐specific effectiveness, optimal targeted age range and intervals in cervical cancer screening and the screening implications of the HPV16/18 vaccines. The background material is based on data from a screening programme with centralized records dating back to 1964, as well as from population‐based studies on the distribution of oncogenic HPV types in cancer and histologically verified CIN2‐3 lesions and from the Icelandic arm of the Future II trial with Gardasil^®. The findings confirm significant increased rates in the screened population of CIN2‐3, stage IA (microinvasive) cancer since 1979, mainly in the age group 20–34 years. These lesions start to accumulate within 3 years of a normal smear. Studies on the distribution of HPV types indicate that the marketed vaccines could lower the incidence of cancer and CIN2‐3 by about 67% and 53%, respectively, after taking into account reported cross‐protection. About 65% of women below 25 years of age had lesions related to the non‐vaccine types and after the last normal smear these cases accumulated at the same frequency as cases with vaccine‐included types. Cases with combined vaccine and non‐vaccine types accumulated at a slower rate. We conclude that screening should continue to start at age 20 years, with invitations at 2‐year intervals up to age 39 years and thereafter at 4‐year intervals up to age 65–69 years. Current data support the conclusion that the optimal age for catch‐up HPV vaccination should be considered in the context of sexual practices and the data do not support changes in the lower age limit or screening intervals for the vaccinated women.     

Use of radiothermometry in the screening of nonpalpable breast neoplasms

As compared with other types of malignancies, breast cancer is one of the commonest causes of female death. Mammography used for screening is associated with radiation exposure and it is of low informative value in women less than 35 years of age. Breast ultrasonography (USG) cannot be used for screening of women less than 35 years of age in whom a glandular component is prevalent in the breast structure as it takes much time and should be performed by a qualified specialist. The purpose of our study was to estimate the diagnostic capacities of microwave radiothermometry (RTM) and to determine its place in the early diagnosis of nonpalpable breast neoplasms in medical practice. An integrated study, including RTM, USG, and mammography, was conducted in women at the District Mammology Department, Diagnostic Center Five, and at Branch One of the Female Health Clinic Diagnostic Center in March 2003 to October 2006. The study covered 200 women aged 35 to 71 years who had neither complaints nor clinical signs of a breast nodule and had been found to have neoplasms after undergoing the above diagnostic studies. The studies performed showed that the sensitivity of RMT diagnosis, USG, and mammography was 86.7, 75.8, and 88.3%, respectively. The precision of these techniques was 75.2, 80.0, and 83%.     

Intraepithelial Carcinoma of the Cervix Uteri in Women Aged under 35 Years

The number of cases of intraepithelial carcinoma of the cervix among women of different age groups has been related to the number of cervical smears from women of the same age groups. Among women aged 25 to 34 years the incidence of intraepithelial carcinoma was 0·67% and among those aged 35 to 44 years it was 0·75%. The overall rate of intraepithelial carcinoma in women under 35 years was 0·55% compared with an overall rate of 0·59% in women over 35 years.If screening of women for cervical cancer is to play any part in preventive medicine it is suggested that the national campaign for the early detection of cervical cancer should be expanded to encourage practitioners to take cervical smears from younger women, particularly from those under 35 years.