Biomedical subjects

R G Blanks

Publications and source records attributed to R G Blanks.

25 records · Page 2Linked to original sources

PubMed1998

A comparison of cancer detection rates achieved by breast cancer screening programmes by number of readers, for one and two view mammography: results from the UK National Health Service breast screening programme.

OBJECTIVE: To determine the increased cancer detection rate, if any, of programmes in the UK National Health Service breast screening programme (NHSBSP) using more than single reading of mammograms. DESIGN: Information on the detection of cancers by individual screening programmes from annual (KC62) returns, supplemented by questionnaire information about the number of readers. SETTING: The 87 NHSBSP programmes from England and Wales for the screening year 1 April 1996 to 31 March 1997. The study includes all programmes for prevalent screens where two views are mandatory, but excludes the four programmes using two view mammography for incident screening. MAIN OUTCOME MEASURES: Cancer detection, invasive cancer detection, and small (< 15 mm) invasive cancer detection by mammographic reading protocol using single reading as the reference level. RESULTS: Programmes collectively using single reading detected the lowest rate of cancers at both prevalent (first) and incident (subsequent) screening. The highest rate of age standardised cancer detection was achieved by programmes using double reading with arbitration. At prevalent screens, where all programmes used two views, those programmes using double reading with arbitration detected 32% (95% confidence interval (CI) 3% to 69%) more small (< 15 mm) invasive cancers than programmes using single reading. At incident screens, where all programmes analysed used one view this increased to 73% (95% CI 40% to 113%). Recall rates showed no obvious difference between single reading and the double reading protocols, being around 7% for prevalent screens and 3.5% for incident screens. DISCUSSION: The results suggest that the increase in cancer detection resulting from increasing the number of readers depends on the number of views, and is higher for one view than two views. Single reading of one view results in a low detection rate of small invasive cancers for most individual programmes. It is, however, recognised that a small number of individual readers may achieve high detection rates with such a protocol. All groups of programmes using different reader/view protocols are on average close to or above target cancer detection rates, except those using single reading of one view (mediolateral oblique) at incident screens.

Breast Neoplasms↗

PubMed1997

Use of two view mammography compared with one view in the detection of small invasive cancers: further results from the National Health Service breast screening programme.

OBJECTIVE: To examine further the effect of using two view mammography in comparison with one view mammography in the detection of small (< 15 mm) invasive cancers for programmes in the National Health Service breast screening programme (NHSBSP). The study is in two parts: first the effect on the small invasive cancer detection rate for programmes that changed from using one view to two views for first (prevalent) screens, and secondly the effect on the small invasive cancer detection rate for programmes that used two views for subsequent (incident) screens compared with programmes that used one view. SETTING: Screening programme data from the NHSBSP. METHODS: Data were collated from all screening programmes in the United Kingdom on standard "Korner" returns (KC62 forms) for the screening years 1 April 1994 to 31 March 1995 and 1 April 1995 to 31 March 1996. The comparison between one and two view mammography was made using indirectly age standardised invasive cancer detection rates. RESULTS: For prevalent (first) screens, programmes changing from one view mammography in 1994/95 to two views in 1995/96 reported a 45% (95% confidence interval (CI) 25% to 68%) increase in the detection of invasive cancers of < 15 mm. In comparison, programmes that were already using two views in 1994/95 showed no change in 1995/96. For incident (subsequent) screens the small number of programmes that have opted to use two views reported 25% (95% CI 1% to 55%) more invasive cancers of < 15mm than programmes using one view in 1995/96, and 42% (95% CI 11% to 81%) more in 1994/95. CONCLUSIONS--These results confirm the benefit of using two view mammography in the detection of small invasive cancers, and provide evidence that this effect is seen in subsequent screens as well as the first screen.

Adult↗

PubMed1997

Influence of number of views and mammographic film density on the detection of invasive cancers: results from the NHS Breast Screening Programme.

The National Health Service Breast Screening Programme (NHSBSP) has recommended the adoption of two view mammography at the prevalent screen, and the use of a target film density in the range 1.4-1.8. The aim of this study was to review the impact of number of views and optical density on the detection of invasive cancers. The last four annual returns for screening centres in the NHSBSP have been analysed retrospectively for 2827342 women aged 50-64 years attending their first (prevalent) screening examination. The detection of invasive cancers was assessed in relation to the number of views and film density using the age adjusted, Standardized Detection Ratio measure of screening performance. Typical film densities were reported for each screening year by local physicists, and the average value for all mammography sets at each programme calculated, and found to vary from 0.85 to 1.85. The mean film density across the NHSBSP rose progressively from 1.30 (SD = 0.21) in 1991/2 to 1.57 (SD = 0.12) in 1994/5. Programmes using single view mammography (MLO) and an optical density less than 1.4 detected 76% (95% CI 74-79%) of the expected invasive cancers. Programmes using two view mammography (MLO and CC) and an optical density equal to or greater than 1.4 detected 95% (95% CI 92-98%) of the expected invasive cancers. In 1994/95 when more programmes used the recommended screening modes, the NHSBSP detected 96% (95% CI 92-101%) of the expected invasive cancers at prevalent screening. The detection of invasive cancers was highest where programmes used two views with a film density in the range 1.4-1.8. The results provide evidence of the benefit of the recommended protocol for prevalent screening and indicate that from 1995/96 when all programmes will be using the recommended protocol, it is likely that the detection rates and interval cancer rates from prevalent screens in the NHSBSP will be close to the figures in the Swedish-Two County Trial.

Breast Neoplasms↗

PubMed1996

Monitoring the performance of breast screening programmes: use of indirect standardisation in evaluating the invasive cancer detection rate.

Close monitoring of data from individual programmes is required to evaluate the potential of the breast screening programme to reach the Health of the Nation target of 25% reduction in breast cancer mortality in the invited age group by the year 2000. This paper outlines the use of indirect age standardisation techniques to compare the performance of individual programmes in terms of their invasive cancer detection rates. Expected invasive cancer detection rates are calculated by applying data from the Swedish two county study to estimated England and Wales background incidence rates for different age strata. If the national programme overall meets these targets then the required mortality reduction should be achieved. The same method can be used by other (national) screening programmes by applying the relevant background incidence figures to produce internationally comparable data.

Age Factors↗

PubMed1996

Monitoring the performance of breast screening programmes: allowing for geographical variation in breast cancer incidence.

Among the myriad of problems associated with evaluating the performance of individual screening programmes in the National Health Service breast screening programme is that of correcting for background breast cancer incidence in the catchment areas of individual programmes. The background incidence will affect not only the expected cancer detection rate at screening, but also the interval cancer rates. This paper proposes a method that can be used to correct for background incidence. The method can be used either to correct the crude cancer detection rate or the age adjusted cancer detection rate using a measure such as the standardised detection ratio. Variation in background incidence and age distribution of screened women are the two major factors affecting the expected cancer detection rate for individual screening programmes. Control of these two variables should allow more effective evaluation of individual screening programme performance.

Aged↗

PubMed1996

A comparison of two view and one view mammography in the detection of small invasive cancers: results from the National Health Service breast screening programme.

OBJECTIVE: To examine the effect of using two view mammography in comparison with one view mammography in the detection of small (< 15 mm) invasive cancers. SETTING: Screening programme data from National Health Service breast screening programme (NHSBSP). METHODS: Data were collated from all screening programmes in the United Kingdom on standard "Korner" returns (KC62 forms) for the screening year 1 April 1994 to 31 March 1995. The comparison of invasive cancer detection rates by programmes using one and two view mammography with indirectly age standardised invasive cancer detection rates. RESULTS: Programmes using two views for women attending their prevalent screen (first screen) in the NHSBSP detected 3% more non-invasive/microinvasive cancers, 7% more large invasive cancers (> or = 15 mm), and 42% more small invasive cancers (< 15 mm) than programmes using one view mammography. CONCLUSIONS: The success of the screening programme depends largely on the ability of individual programmes to detect small invasive cancers. The results suggest that the benefit of using two view mammography is largely in the increased detection of these cancers.

Breast Neoplasms↗

PubMed1992

Is cadmium a human carcinogen?

Continuing observations on cadmium-exposed workers have failed to yield evidence of an increased mortality from prostatic cancer, as initially suspected. There is, however, evidence of an increased mortality from lung cancer and, in at least two of the studies, of a dose-response relationship, but interpretation of these studies with regard to the role of cadmium is complicated by concurrent exposure to other known or suspected carcinogens, including arsenic, nickel, beryllium, chromium and heated mineral oils. An update of a long-term cohort mortality study from 17 plants in England employing a wide range of cadmium processes, while confirming an increased lung cancer risk related to intensity of cadmium exposure, shows some evidence of this risk also being associated with exposure to arsenic. It is thus not possible at present to attribute the excess mortality from lung cancer to cadmium owing to the presence of multiple confounding factors in the populations studied. Their role in the 17-plant study is currently being further investigated.

Animals↗