The efficacy of double reading mammograms in breast screening.

The effect of double reporting the screening mammograms of 31,146 women attending as part of the UK National Health Service Breast Screening Programme was analysed. Ninety per cent had their mammograms read by two of three experienced radiologists. Overall 1846 (5.9%) women were recalled for further assessment. Two hundred and sixty-one patients (0.8%) underwent surgical intervention resulting in the detection of 191 cancers (6.1/1000 women screened). The benign-to-malignant ratio was 1:3.6 (PPV 73.2%). Of the invasive cancers detected 72% had no histological evidence of axillary lymph node metastases. Twenty-one of the 191 cancers detected (10.4%) were missed by one of the two reporters. Six of these were invasive cancers < or = 1 cm in diameter. Comparison of those lesions detected by both readers to those detected by only one, showed readers were more likely to detect those lesions appearing as an opacity (65% vs 38%), but less likely to detect significant microcalcification (15% vs 33%). The difference between the two groups when taken as a whole, however, failed to reach statistical significance (chi 2 = 6.76, d.f. = 3, P = 0.08). In summary, double reporting resulted in an increase in sensitivity of 10%. However, there was a decrease in specificity of 1.8% with 569 women being recalled unnecessarily for assessment and biopsy of 13 benign lesions. The estimated resultant additional financial cost was 13773 pounds.

Assessment of non-palpable mammographic abnormalities: comparison between screening and symptomatic clinics.

A retrospective study found that a breast screening clinic generated fewer localization biopsies for non-palpable mammographic abnormalities than a symptomatic clinic (3.36 versus 9.89 per 1000 mammograms, respectively) and that a greater proportion of such biopsies were malignant. This study determined the reason for this difference. There were 108 of 304 (35.5 per cent) and 17 of 130 (13.1 per cent) carcinomas in women attending the screening and breast clinics respectively (relative risk 2.72 (95 per cent confidence interval 1.70-4.34)). This difference was regardless of age. The characteristics of the mammographic abnormality, the Wolfe pattern, a family history of breast carcinoma, parity and age at first pregnancy were similar in both groups. Women attending the screening clinic were referred for localization biopsy after assessment by clinicians and radiologists at a joint clinic; there was no joint assessment for patients attending the breast clinic. The same staff attended both clinics, although the proportion of time spent at each varied. This study suggests that all women with a non-palpable mammographic abnormality should be reviewed at a joint assessment clinic before localization biopsy is recommended.

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.

The role of radiology in the assessment of bladder cancer.

Bipedal lymphography and intravenous urography were carried out in 44 patients in an attempt to define the role of these procedures in the assessment of the patient with carcinoma of the bladder. Evidence of lymphatic involvement, even though unsupported by histological proof and a major abnormality on urography, conferred a worse prognosis than if these examinations were thought to be normal. Implications for therapy are considered.