Chest x ray screening for lung cancer at three British chromates plants from 1955 to 1989.

Chest x ray screening for lung cancer had been undertaken over a period of 34 years, initially at yearly intervals, then at eight-monthly intervals, on chromates workers at three plants in the United Kingdom. A review of the records of 229 employees who were diagnosed as having carcinoma of the lung during the screening programme was conducted. Survival data were available on 124 cases (123 now deceased) who constitute the study population. The cases were analysed by age and regularity of attendance for screening. The numbers detected by works x ray screening and by other means were determined with five and 10 year survival rates. A modest but predictable improvement in the five year survival of those who attended regularly for radiography was shown. Taking the total population of cases for whom screening was available, no significant improvement in five year survival was found.     

Risk group chest X-ray for the early detection of lung cancer

In Hungary, one of the most important components of anti-TB fight was the initiation of chest X-ray based obligatory and yearly screening of the population. In the 1970s, approximately the entire adult population was regularly screened for lung diseases. However, with the improvement of TB epidemiology, early detection of lung cancer--as a "byproduct" of X-ray screening--seems to have a growing significance. In the near future, concentration needs to be given to the risk group for lung cancer, namely smokers who are older than 40 years. To demonstrate the advances of the above strategy, we investigated the lung cancer prevalence in Budapest, retrospectively. Based on the data of 2511 patients, we found that 60% of the patients with 5-year survival were identified with screening. The operability rate was 34% in the group of patients identified by screening. This was only 14% in the case of patients who had been identified based on their symptoms at the time of diagnosis. We also found that radical tumor resection offers a significant short-term (3-4 years) survival advantage, because of the long-term recurrence of the tumors, the overall mortality rate remains unchanged in the target population. Based on the current screening data, there is a chance for short-term survival advantage for 5-600 patients in every year. With the screening of the risk population (smokers, >40 years), the operability rate could be improved which, in turn, could offer a prolonged survival for 1100-1200 lung cancer patients.     

The public health management of tuberculosis among the single homeless: is mass miniature x ray screening effective?

STUDY OBJECTIVE--The aim was to test the assumption that mass miniature x ray screening of the single homeless (hostel residents) is a cost-effective means of controlling pulmonary tuberculosis. DESIGN--The study was a prospective experimental screening exercise to identify new cases of active tuberculosis completing treatment. SETTING--The setting was eight hostels in south London. A mobile x ray screening facility was set up outside the hostels. SUBJECTS--Subjects were 547 single homeless residents in the hostels. They were encouraged to attend for chest x ray, and for active follow up of abnormal x rays. MAIN RESULTS--No new cases of active tuberculosis were found. CONCLUSIONS--Mass miniature x ray is ineffective in controlling tuberculosis because of its unacceptability and increasing inaccessibility to this population.     

Surveillance for tuberculosis among residents of hostels for homeless men

Abstract: Tuberculosis has been recognised as an important health problem among homeless persons. The New South Wales tuberculosis screening program for residents of hostels for the homeless has been in operation for several years, but has not yet been evaluated. This study reviewed the performance of the tuberculosis surveillance program (which uses mobile chest x–ray screening) between 1989 and 1993 at the five major hostels for homeless men in the eastern Sydney area. Reports of the screening x–rays and records of subsequent follow–up examinations at chest clinics were examined; information on cases detected by the screening program was compared with notifications in the same population. Of 3555 residents screened during 23 visits, 506 (14.2 per cent) were found to have an abnormal chest x–ray. However, only two active cases of tuberculosis were diagnosed as a result of the screening program, while seven cases were notified on the basis of clinical presentation. About 50 per cent of those with an abnormal chest x–ray from the screening program were lost to follow–up. Possible reasons for loss to follow–up were: long delays in making chest clinic appointments; short–stay residents changing shelters without trace; and high prevalence of severe mental illness or organic brain syndrome among residents. Raising awareness of the disease among primary health care and welfare staff who work with homeless men may be a more effective approach to improving identification of cases of active tuberculosis in this population. ( Aust N Z J Public Health 1997; 21: 447–50)     

Breast screening clinic versus health education session as outlets for education in breast self-examination.

A population based programme to educate women in breast self-examination (BSE) was organised as part of the UK Trial of Early Detection of Breast Cancer. Women who responded to an invitation to a meeting were educated in groups and were not routinely screened. Open access clinics offered x ray and clinical examination to all women in the study age group of 45 to 64. Women who presented for screening without prior BSE education were taught individually by clinic staff. Women taught by the two methods were surveyed by post and their BSE practice since education was compared. It was hypothesised that the women taught in clinics, who had been reassured of their breast normality, would practice BSE more regularly and correctly. Results did not confirm this hypothesis. Lower standards of practise and a higher level of anxiety at the time of survey were found in the group who presented at a free access clinic and had received individual teaching at the time of screening.     

Non-malignant chest x ray changes in patients with mesothelioma in a large cohort of asbestos insulation workers.

To assess the prevalence of non-malignant chest x ray abnormalities in cases of mesothelioma 184 cases of mesothelioma (72 pleural and 112 peritoneal) which had occurred in a cohort of asbestos insulation workers followed up since 1967 were studied. Chest x ray films of satisfactory quality, on which the presence or absence of non-malignant radiological changes indicating interstitial pulmonary fibrosis or pleural fibrosis or both, could be assessed with a high degree of certainty were available. In some cases (20% for pleural mesothelioma, 11.6% for peritoneal mesothelioma) non-malignant radiological changes were not radiologically detectable. Parenchymal interstitial fibrosis (small irregular opacities) only was found in a proportion of cases (25.4% of pleural mesotheliomas, 12.5% of peritoneal mesotheliomas). Pleural fibrosis only was detected in 17% of cases of pleural mesothelioma and 27% of cases of peritoneal mesothelioma. Most patients had both parenchymal and pleural fibrosis. Although these results tend to indicate that in peritoneal mesothelioma the proportion of pleural fibrosis is significantly higher, these findings might have been due to the fact that in most cases of pleural mesothelioma non-malignant changes were interpreted in one hemithorax only. In 46 cases (21 pleural, 25 peritoneal) in which sufficient lung tissue was available histopathology of lung parenchyma indicated the presence of interstitial fibrosis; in 20 (43.5%) of these the chest x ray film had been read as negative. Thus the absence of radiologically detectable small opacities on the chest x ray film does not exclude the existence of interstitial pulmonary fibrosis in cases of mesothelioma among insulation workers. With lower levels of exposure (such as in family contacts of asbestos workers) it is conceivable that mesothelioma might occur in the absence of interstitial pulmonary fibrosis.     

Non-malignant chest x ray changes in patients with mesothelioma in a large cohort of asbestos insulation workers

To assess the prevalence of non-malignant chest x ray abnormalities in cases of mesothelioma 184 cases of mesothelioma (72 pleural and 112 peritoneal) which had occurred in a cohort of asbestos insulation workers followed up since 1967 were studied. Chest x ray films of satisfactory quality, on which the presence or absence of non-malignant radiological changes indicating interstitial pulmonary fibrosis or pleural fibrosis or both, could be assessed with a high degree of certainty were available. In some cases (20% for pleural mesothelioma, 11.6% for peritoneal mesothelioma) non-malignant radiological changes were not radiologically detectable. Parenchymal interstitial fibrosis (small irregular opacities) only was found in a proportion of cases (25.4% of pleural mesotheliomas, 12.5% of peritoneal mesotheliomas). Pleural fibrosis only was detected in 17% of cases of pleural mesothelioma and 27% of cases of peritoneal mesothelioma. Most patients had both parenchymal and pleural fibrosis. Although these results tend to indicate that in peritoneal mesothelioma the proportion of pleural fibrosis is significantly higher, these findings might have been due to the fact that in most cases of pleural mesothelioma non-malignant changes were interpreted in one hemithorax only. In 46 cases (21 pleural, 25 peritoneal) in which sufficient lung tissue was available histopathology of lung parenchyma indicated the presence of interstitial fibrosis; in 20 (43.5%) of these the chest x ray film had been read as negative. Thus the absence of radiologically detectable small opacities on the chest x ray film does not exclude the existence of interstitial pulmonary fibrosis in cases of mesothelioma among insulation workers. With lower levels of exposure (such as in family contacts of asbestos workers) it is conceivable that mesothelioma might occur in the absence of interstitial pulmonary fibrosis.     

Annual chest X-ray in patients after treatment for laryngeal or oral cancer: only a limited number of second primary lung cancers detected]

OBJECTIVE: To evaluate the detection of second primary lung cancer in patients treated for laryngeal or oral cancer by means of the current annual chest radiography screening program. DESIGN: Retrospective follow-up. METHOD: In a source population of Utrecht University Hospital consisting of patients treated for laryngeal or oral cancer, the occurrence of non-simultaneous second primary lung cancer was analysed. The charts of the patients who developed second primary lung cancer were reviewed with respect to diagnosis (either by means of routine annual chest radiography or triggered by symptoms and signs) and treatment of lung cancer. A Kaplan-Meier survival analysis was performed for both routes of diagnosis and for each form of lung cancer treatment. RESULTS: The source population consisted of 2067 patients. Second primary lung cancer was diagnosed in 44 patients (37 with laryngeal and 7 with oral cancer). In 21 patients lung cancer was diagnosed by means of annual chest radiography (routine group). The remaining 23 patients presented with symptoms and signs (symptomatic group). In 13 patients, surgery with curative intent was performed. These patients had the best prognosis. Of the surgical cases, 12 out of 13 patients (27% of the total of 44) were in the routine group. Patients in the routine group had better survival than those in the symptomatic group. CONCLUSION: In view of the limited number of patients with second primary lung cancer and the small percentage of patients eligible for curative surgical treatment detected by annual radiography, screening in its present form is of little benefit.     

Trends in survival rates of cancer in Cuba

Reports of population-based survival rates of cancer from developing countries are infrequent. In Latin America, only the Cancer Registry of Puerto Rico has published population-based survival data. The National Cancer Registry of Cuba has achieved three survival studies with cases incident in 1976, 1982 and 1988–1989. This article deals with the global observed and relative survival rates estimated in the latter study. Survival time trends are analysed. In the period 1988–1989, 12,985 primary cancer cases were included from the most common cancer sites, with the exclusion of cancer in situ cases and 8900 cases reported by death certificate only (DCO) (35.8%). The vital status of cases was checked up to 31 December 1994 using a mixed follow-up system with the exclusion of 2900 cases lost to follow-up (11.2%). DCO proportions are shown for the major sites and compared to those of 1982. Observed survival rates were estimated by Kaplan–Meier method using the SPSS Statistical Software. The relative rates were estimated by the Hakulinen's Computer Program Package for Cancer Survival Studies (1988) using life tables from Cuban population. Statistical comparisons of survival curves by year of diagnosis were achieved by using the Log–Rank and Pearson statistic tests. Global results are shown by year of follow-up and a comparative analysis is done in time and with internationals values. Survival rates decreased in the period 1982/1988–1989 for colon, prostate and lung cancer. Prostate cancer shows a low five years relative survival rate when compared with the USA, but its observed rate is comparable with Puerto Rico's. Figures for mouth and lung cancer were comparable with the corresponding figures of the USA and Europe. Breast and cervix cancers rates are comparable with the European mean and the blacks in USA.     

乌鲁木齐市2014年城市癌症早诊早治筛查效果分析

目的　分析乌鲁木齐2014年城市居民癌症高风险率、筛查率和检出率,为开展癌症早诊早治项目工作提供依据。方法　在乌鲁木齐市选择4个辖区,选定目标街道和社区后,以社区为单位动员所有40～69岁常住户籍居民,按照知情同意自愿的原则接受有关癌症的流行病学问卷调查和高风险评估。检出的高风险对象免费接受肺癌、肝癌、上消化道癌、女性乳腺癌和大肠癌临床筛查,分析评估癌症的高风险率、筛查率和检出率。结果 本研究共完成49 574名有效调查和风险评估,其中肺癌、肝癌、上消化道癌、女性乳腺癌和大肠癌的高风险检出率分别为13.25 %、12.03%、20.38 %、18.36%和14.21%。5类癌症高风险率中上消化道癌最高,各种癌症风险率之间差异均有统计学意义(x2=1785,P﹤0.05);肺癌的高风险率高于肝癌,但差异无统计学意(x2=1.602,P=0.21),肺癌男性高风险率是女性的3.69倍,肝癌男性高风险率是女性的1.25倍,肝癌各年龄组间的高风险检出率差异有统计学意义(x2=57.76,P﹤0.05)。单癌种、两癌种、三癌种、四癌种和五癌种同时高风险的比例依次为26.86%、9.68 %、4.50%、2.62%和0.35%。五类癌的筛查率分别为肺癌37.36%、肝癌 41.27%、上消化道癌19.82%、乳腺癌45.53%和大肠癌16.61%。肺癌或疑似肺癌检出率为0.49%,可疑肝癌检出率为0.12%,上消化道癌检出率为0.15% ,乳腺B超＋钼靶BI-RADS4-5级检出率为2.27%,大肠癌检出率为0.17%。结论　需要进一步完善城市癌症早诊早治技术方案和管理模式,提高筛查率和早诊早治效果。     

Health Disparities Across Lung Cancer Continuum Among Asian Americans: A Systematic Review

The purpose of this systematic review is to synthesize lung cancer associated health disparities across the cancer continuum among Asian Americans. A systematic review design with the narrative method was used for conducting this study. Electronic literature databases, including PubMed, Google Scholar, and CINAHL, were searched. After applying filter information, inclusion and exclusion criteria, a total of 20 articles were included in the review. Findings related to lung cancer prevention, screening, incidence rates, diagnosis, treatment, survival rates, and mortality rates among Asian Americans were synthesized. Results showed the prevalence of smoking quit attempts in the past year was high among Asian Americans, although the prevalence of receiving advice to quit and using counseling and/or medication services was low among this population. Also, the smoking cessation rate among Asian Americans was the second lowest among all racial groups, although the abstinence rate was highest among this population. Compared with other races, Asian Americans are more likely to be diagnosed with lung cancer at a distant stage of disease, and they tend to be less likely to undergo surgery than other races in the United States. The incidence and mortality rates of lung cancer were low among Asian Americans compared with other races in the United States, while the survival rate of lung cancer was high among this population. Further research focusing on lung cancer associated health disparities in specific Asian American ethnic groups should be conducted. Culturally relevant programs that tackle cultural and genetic factors related to lung cancer risk as well as early screening, diagnosis and treatment in this vulnerable population are also necessary.

     

Exposure and mineralogical correlates of pulmonary fibrosis in chrysotile asbestos workers.

OBJECTIVES: The relation between lifetime cumulative exposure to asbestos, pathological grade of pulmonary fibrosis, and lung burden of asbestos at death, was explored in a necropsy population of former workers in a chrysotile asbestos textile plant in South Carolina. METHODS: Estimates of cumulative, mean, and peak exposures to asbestos were available for 54 workers. Necropsy records and lung tissue samples were obtained from hospital files. Matched control cases were selected from consecutive necropsies performed at the same hospitals. The extent and severity of pulmonary fibrosis was graded on tissue sections. Mineral fibres in lung tissue were characterised by transmission electron microscopy combined with x ray spectroscopy. RESULTS: A significant positive correlation (r = 0.67, P < 0.0001) was found between lifetime cumulative exposure to asbestos and total lung burden of asbestos fibres. This relation was also found for the individual types of asbestos associated with the exposure: chrysotile and tremolite. Pulmonary fibrosis was correlated with both cumulative exposure to asbestos (r = 0.60, P < 0.01) and the concentration of asbestos fibres in the lung (r = 0.62, P < 0.0001). The concentration of tremolite fibres in the lung provided a better estimate of lung fibrosis than did the concentration of chrysotile. Asbestosis was usually present in asbestos textile workers with more than 20 fibre-years cumulative exposure. The lengths and aspect ratios of chrysotile asbestos, but not amphibole asbestos, were greater in the lungs of asbestos fibre workers than in the control population. Textile workers with lung cancer had significantly greater cumulative exposures and fibrosis scores than workers without lung cancer. CONCLUSIONS: Both cumulative exposure to asbestos and lung fibre burden are strongly correlated with severity of asbestosis. The data also support the hypothesis that the high prevalence of asbestosis and lung cancer in this population resulted from exposure to long fibres of chrysotile asbestos in the workplace.     

Analyses of the 1990 chest health survey of china clay workers.

During 1990 all present and retired china clay workers in the United Kingdom were invited to take part in a chest health survey. A total of 4401 china clay workers participated representing over 70% of current employees and 17% of pensioners. The survey consisted of a chest x ray film, lung function measurements, and a questionnaire on respiratory symptoms and smoking habits. The chest x ray films were read by three readers to the International Labour Office (ILO) 1980 classification. Full details of occupational history for each participant were available and for each employee an estimate of total exposure to china clay dust was derived from representative dust concentrations for each location and job. These were based on measured dust concentrations after 1978 and on estimates before 1978. Analyses of the data were carried out to investigate the relations between exposure, x ray film category, lung function, and respiratory symptoms. The percentage of people with small opacities greater than major x ray film category 1 was 0.8% (lower than in previous studies). Dust concentrations have been reduced in recent years, averaging 1.7 mg m-3 for dryers in 1990 compared with 3.5 mg m-3 in 1978. The lower effect of exposure after 1971, compared with earlier exposure, was confirmed by the analyses. After 1971 the milling of dried china clay (Atritor mills) was found to be the occupation with the highest effect on x ray film category. The relation between total exposure to china clay dust and x ray film category is such that a typical non-smoker worker employed in the most dusty of current occupations may expect to reach the lower limit of category 1 after about 42 years continuous employment in that job at current exposures. Both forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were found (as in other studies) to decline with age, more rapidly for smokers than non-smokers at the rates for FVC of 0.035 l/y and 0.033 l/y, whereas for FEV1 the rates are 0.039 l/y for smokers and 0.034 l/y for non-smokers. Changes in x ray film category are also related to lung function , a change of one major category being equivalent to about six years of aging in its effect on FEV1.     

Development of a brief questionnaire for screening for multiple chemical sensitivity syndrome

The objective of this study was to identify a parsimonious set of questions that has high sensitivity and specificity for screening for individuals with multiple chemical sensitivity (MCS) syndrome. We performed a cross-sectional survey using a case-control design. Subjects were derived from patients seen at an academically based Occupational and Environmental Medicine Clinic. Cases consisted of patients who fulfilled the Cullen definition for MCS. Controls were patients who had diagnoses excluding MCS and asthma and who were matched to cases by age and sex. Cases and controls filled out a screening questionnaire that, among things, elicited responses as to whether and how subjects reacted to 122 different types of environmental exposures. Data from 44 pairs of cases and controls were available for analysis. The average age of cases was 50.2 years, and 91% was female. Among cases, the most common exposure that was purported to incite MCS was 'indoor air quality contaminants (unspecified)' (59%), followed by solvents (27.3%). After randomly excluding five cases and controls, a stepwise selection procedure for two-group discriminant analysis revealed that the main contributors to the discrimination of the remaining cases and controls were self-reported reactions to copy machine emissions, marking pens, aftershave, window cleaner, nylon fabric, pine-scented products, and rayon material. When a positive response to these factors was used as the sole method for discriminating cases from controls, only one of 41 cases was misclassified as a control while none of the controls was misclassified as a case. When the same method was applied to the five excluded cases and five excluded controls, only one of the five cases was misclassified while none of the five controls was misclassified as a case. Among patients with MCS defined by the Cullen criteria in this clinical setting, having a reaction to these seven common potential exposures comprised a parsimonious set of factors that discriminated between MCS patients and age- and sex-matched normal controls. These questions may have utility in screening for individuals with MCS in general population survey studies.     

CT检查在石棉肺诊断中的价值

目的　研究石棉肺的肺实质和胸膜病变的ＣＴ 检查所见。方法　对１９ 例石棉肺患者进行胸部Ｘ 线和ＣＴ 检查, 比较Ｘ 线和ＣＴ 检查对石棉肺患者肺实质改变和胸膜改变的表现特点和检出结果。结果　Ｘ 线胸片有胸膜改变的５例, 其中１ 例为胸膜斑。ＣＴ 检查发现有胸膜改变的１６ 例, 其中６ 例为胸膜斑; ６ 例有胸膜斑的病例中, 有３ 例为Ｘ 线胸片上难以发现的脊椎旁胸膜斑。肺实质改变, 在Ｘ 线胸片上, 在３ 个病例各发现１ 个大阴影; 而ＣＴ 检查, 在４ 个病例中, 共发现５ 个大阴影, 其中１ 例伴有胸膜下曲线状肺纤维化阴影。肺内小阴影的显示, ＣＴ 检查所见不如Ｘ 线所见的密集。结论　联合应用胸部Ｘ 线和ＣＴ 检查结果, 可为石棉肺的诊断和分级提供较有价值的信息。     

Asbestosis occurring after brief inhalational exposure: usefulness of bronchoalveolar lavage in diagnosis.

A case of clinically and radiologically typical asbestosis manifesting in a 55 year old man occurred 36 years after a brief exposure period of less than one year. A transbronchial lung biopsy was performed but the samples were considered non-diagnostic. The diagnosis was supported by the use of bronchoalveolar lavage to obtain alveolar samples and scanning electron microscopy-energy dispersive x ray analysis of fibres found in the bronchoalveolar lavage fluid which showed a predominance of amosite.     

Asbestosis occurring after brief inhalational exposure: usefulness of bronchoalveolar lavage in diagnosis

A case of clinically and radiologically typical asbestosis manifesting in a 55 year old man occurred 36 years after a brief exposure period of less than one year. A transbronchial lung biopsy was performed but the samples were considered non-diagnostic. The diagnosis was supported by the use of bronchoalveolar lavage to obtain alveolar samples and scanning electron microscopy-energy dispersive x ray analysis of fibres found in the bronchoalveolar lavage fluid which showed a predominance of amosite.     

Time interval since last test in a breast cancer screening programme: a case-control study in Italy.

STUDY OBJECTIVE: To evaluate a population based screening programme for breast cancer. DESIGN: This was a case-control study of women dying of breast cancer between 1977 and 1987 who had been invited to take part in a screening programme. SETTING: Community based study of women aged between 40 and 70 years (total population about 35,000 at 1981 census), living in 23 small towns near Florence, Italy. PARTICIPANTS: 103 cases were identified from death certification, and 515 living controls (five per case) selected for year of birth and town of residence. MEASUREMENTS AND MAIN RESULTS: Screening history was obtained from computer archive. Sociodemographic information was obtained from town registry offices and directly from relatives of the deceased and from the controls by postal questionnaire, and if necessary telephone or personal interview. Analysis was carried out on two age groups--40-49 years and 50+ years at diagnosis--and considered the number of screening tests and the time interval since the last test, separately and together. In the older age group, women with at least one screening test in the previous 2 1/2 years showed a 50% reduction in risk (odds ratio 0.49, 95% confidence interval [CI] 0.25-0.95). If they had also had another previous negative screen the risk was reduced to one third (odds ratio 0.35, 95% CI 0.14-0.85). There was a significant trend of decreasing risk with increasing number of screens in older women. No clear evidence of a similar protective effect was shown for women in the 40-49 year age group. CONCLUSIONS: A significant protective effect of the screening programme is evident in older women but not in younger ones. The data do not allow an assessment of optimal screening interval because of the small number of previously screened cases.     

Tuberculosis among the homeless at a temporary shelter in London: report of a chest x ray screening programme.

STUDY OBJECTIVE--To estimate the prevalence of active pulmonary tuberculosis in a homeless population in London and to assess whether those with suspected disease could be integrated into the existing health care system for further follow up and treatment. DESIGN--Voluntary screening programme based on a questionnaire survey and chest x ray. SETTING AND CASES--Screening programmes were set up over the Christmas period in 1992 and 1993 at a shelter for the homeless in London. An offer of screening was made to all individuals who visited the centre and an interviewer administered questionnaire was completed on those who volunteered for the screening. Chest x rays were carried out, developed, and read on site. Individuals with chest x rays features suggestive of tuberculosis or other medical problems were referred to a hospital of their choice. RESULTS AND OUTCOME--In 1992 nearly 1600 people visited the centre, of whom 372 volunteered for the screening and 342 were x rayed. Nineteen of the 342 (5.6%) had radiological features suggestive of active tuberculosis. In 1993 around 2000 homeless people visited the centre, of whom 270 volunteered for the screening and 253 were x rayed. Eleven (4.3%) had features consistent with active tuberculosis on the basis of the chest x rays and clinical examination by a chest physician. Overall, of 595 people x rayed in the two surveys, 30 (5%) had changes suggestive of active tuberculosis. Further investigations confirmed nine (1.5%) with active pulmonary disease and eight with no active tuberculosis. In 13, the diagnosis was not determined as four declined further investigation and nine did not attend their hospital appointment. CONCLUSION--Tuberculosis among the homeless remains a cause for concern. Follow up and treatment present unique difficulties. Services for the homeless need to include mechanisms for timely diagnosis and monitored treatment. Control programmes designed for the needs of the homeless are required.