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Biomedical subjects

F E Alexander

Publications and source records attributed to F E Alexander.

96 records · Page 6Linked to original sources
PubMed1988

Use of risk factors to allocate schedules for breast cancer screening.

In an effort to reduce the cost of breast cancer screening several studies have explored the possibility of using risk factors to select a high-risk group of women and then restrict screening to that group. The results of these studies have been almost entirely negative and so it is not possible at present to classify any woman as at such low risk that she need not be screened. Nevertheless it is well known that some groups of women can be identified as being at higher risk than the general population. In this study it is assumed that each woman will be offered one screen at which risk factor information will be collected. The usual screening policy is then one of uniform intervention in which the interval to the next screen is the same for all women: the interval that is currently recommended in the UK is three years. An alternative is a risk strategy in which the time to the next screen depends on the woman's risk status; thus the total number of screens available to the population are distributed according to risk status. Using data from the Edinburgh randomised trial of breast cancer screening these policies have been compared. It is estimated that the proportion of cases detected by screening in the three years following the completion of the initial screening round could be raised from 60% to 67% by adopting a risk strategy. Lead time benefits are also quantified as are the comparisons for an established screening programme.

Age Factors↗
PubMed1987

Association between mortality among women and socioeconomic factors in general practices in Edinburgh: an application of small area statistics.

Women aged 45-64 in 78 general practices in the city of Edinburgh were followed up for five to seven years and all cause mortality noted. Standardised mortality ratios were calculated for the individual practices. Postcodes were available for a 20% sample of these women and were used to retrieve relevant measures of social class and deprivation from the 1981 census for the smallest division, the enumeration district. Weighted averages gave socioeconomic variables at the level of the general practice. High positive correlations were found between standardised mortality ratios and the socioeconomic variables, with the highest being for percentage overcrowding. This study established that the relation between deprivation and excess mortality can be shown in general practices in one large city and gave a direct relation for women without reference to their husbands' occupations, thus obviating problems of assigning social class. The data also partially refute the "social drift" hypothesis as an explanation of the association between mortality and social class.

Female↗
PubMed1987

Oestrogen receptor activity in breast cancer detected at a prevalence screening examination.

In view of the possible introduction of screening programmes, this study compares oestrogen receptor (ER) levels in a series of women whose primary tumour was detected by screening and an age-matched consecutive series of women whose tumours were diagnosed after symptomatic presentation. Because of missing data and other statistical considerations, the comparison was made using T1 and T2 categories of tumour only. Some differences were found: the distribution of ER levels was significantly different in the two groups, with more extreme values in the symptomatic series; the screening series, however, had more moderate/rich ER levels than the symptomatic group. Tumours of special pathological type (for example, tubular, cribriform, lobular, medullary, and mucoid) were more likely to be ER-moderate or -rich, and there were more of these tumours in the screening series. The relationship of these findings to tumour growth rate is discussed. The study highlights the difficulty of obtaining sufficient tissue for conventional DCC biochemical assays from the small non-invasive tumours found by screening, and suggests that newer alternative methods employing monoclonal antibodies may be required for such types of tumour.

Aged↗
PubMed1987

Risk factors for breast cancer with applications to selection for the prevalence screen.

There have been many studies of individual risk factors for breast cancer; most of the factors concerned may be broadly grouped into demographic and dietary, reproductive history, endocrine related, family history of breast cancer, and previous history of breast disease. Some of these studies have examined the combined effect of these factors. The present case-control study does this in the context of a randomised controlled trial of breast cancer screening. The relative risks that we have obtained are, in general, of similar magnitude to those in other reports. The relevance of the results to a screening programme is discussed.

Age Factors↗
PubMed1984

The Edinburgh randomised trial of screening for breast cancer: description of method.

Edinburgh was selected as one of the centres in the UK Seven-year Trial of Breast Screening of women aged 45-65 which began in 1979. Subsequently, our study was extended to a randomised trial with its own control population within the city. Half the practices were randomly allocated for screening, giving a cluster sampling of women. The total number in the trial is 65,000. Women with previously diagnosed breast cancer are excluded. Women allocated for screening are invited to the clinic and screened according to the procedures specified in the U.K. protocol, having clinical examination every year and mammography on alternate years. The two modalities of screening are assessed independently and the role of nurses is being evaluated. Breast cancer incidence is monitored by pathology register and the local cancer registry office and deaths from the General Register office. Long-term follow-up will be obtained through flagging at NHS Central Register. To determine the value of screening, standard statistical methods will be used to compare breast cancer mortality rates in the whole of the screening population with that of the controls. This trial has a power of 83% of detecting a reduction in mortality of 35% after 7 years of follow-up and a power of 95% of detecting a similar reduction at 10 years (alpha = 0.05, one-sided test).

Breast Neoplasms↗