An analysis of 11.3 million screening tests examining the association between needle biopsy rates and cancer detection rates in the English NHS Breast Cancer Screening Programme

AIM

To examine the association between recall, needle biopsy, and cancer detection rates to inform the setting of target ranges to optimise the benefit to harm ratio of breast screening programmes.

MATERIALS AND METHODS

Annual screening programme information from 2009/10 to 2015/16 for the 80 screening units of the English National Health Service Breast Screening Programme (totalling 11.3 million screening tests) was obtained from annual (KC62) returns. Linear regression models were used to examine the association between needle biopsy rates and recall rates and non-linear regression models to examine the association between cancer detection rates and needle biopsy rates.

RESULTS

The models show and quantify the diminishing returns for prevalent screens with increasing biopsy rates. A biopsy rate increase from 10 to 20 per 1,000 increases the cancer detection rate by 2.13 per 1,000 with four extra biopsies per extra cancer detected. Increasing the biopsy rate from 40 to 50 per 1,000, increases the cancer detection rate by only 0.25 per 1,000, with 40 extra biopsies per extra cancer detected. Although diminishing returns are also seen at incident screens, screening is generally more efficient.

CONCLUSIONS

Increasing needle biopsy rates leads to rapidly diminishing returns in cancer detection and a marked increase in non-malignant/benign needle biopsies. Much of the harms associated with screening in terms of false-positive recall rates and non-cancer biopsies occur at prevalent screens with much lower rates at incident screens. Needle biopsy rate targets should be considered together with recall rate targets to maximise benefit and minimise harm.

Increasing the diagnosis of multifocal primary breast cancer by the use of bilateral whole-breast ultrasound

AIM

The aim of this study was to evaluate the contribution of bilateral whole-breast ultrasound (BBUS) to the diagnosis and management of women with newly diagnosed breast cancer.

METHODS

Over a period of 6 months, 102 women presenting with breast cancer underwent BBUS. Data were collected on clinical findings, radiology, histology and surgical outcome. These women were compared with a control group of 124 women presenting over a similar 6-month period 1 year previously, who had undergone targeted breast ultrasound.

RESULTS

Multicentric/multifocal tumours were demonstrated in 35 (34%) of the 102 participants and in 18 (15%) of the 124 controls, a statistically significant difference (Fisher's exact test, p = 0.001). Multiple tumours were diagnosed preoperatively in 18% of the study population compared with 8% of the controls, and BBUS identified invasive multifocal/multicentric tumours in significantly more women in the study population (11 versus 1 control) (Fisher's exact test, p = 0.019). Contralateral cancer was diagnosed in 4 women in the study population and none in the control population (Fisher's exact test, p = 0.040). Surgical review showed that the surgical management changed significantly in 8% (95% confidence interval 4 to 14%) of cases in the study population following BBUS. The increase in the number of women undergoing benign biopsies in the study population (10 versus 5 controls) was not statistically significant (Fisher's exact test, p = 0.11).

CONCLUSION

BBUS increased the preoperative diagnosis of multiple tumours in women presenting with primary breast cancer, resulting in a management change in 8% of cases.

Impact of computer-aided detection prompts on the sensitivity and specificity of screening mammography

OBJECTIVES

To determine the value of computer-aided detection (CAD) for breast cancer screening.

DESIGN

Two sets of mammograms with known outcomes were used in two studies. Participants in both studies read the films with and without the benefit of a computer aid. In both studies, the order of reading sessions was randomised separately for each reader. The first set of 180 films, used in study 1, included 20 false-negative interval cancers and 40 screen-detected cancers. The second set of 120 films, used in study 2, was designed to be favourable to CAD: all 44 cancer cases had previously been missed by a film reader and cancers prompted by CAD were preferentially included.

SETTING

The studies were conducted at five UK screening centres between January 2001 and April 2003.

PARTICIPANTS

Thirty radiologists, five breast clinicians and 15 radiographers participated.

INTERVENTIONS

All cases in the trial were digitised and analysed using the R2 ImageChecker version 2.2. Participants all received training on the use of CAD. In the intervention condition, participants interpreted cases with a prompt sheet on which regions of potential abnormality were indicated.

MAIN OUTCOME MEASURES

The sensitivity and specificity of participants were measured in both intervention and control conditions.

RESULTS

No significant difference was found for readers' sensitivity or specificity between the prompted and unprompted conditions in study 1 [95% confidence index (CI) for sensitivity with and without CAD is 0.76 to 0.80, for specificity it is 0.81 to 0.86 without CAD and 0.81 to 0.87 with CAD]. No statistically significant difference was found between the sensitivity and specificity of different groups of film reader (95% CI for unprompted sensitivity of radiologists was 0.75 to 0.81, for radiographers it was 0.71 to 0.81, prompted sensitivity was 0.76 to 0.81 for radiologists and 0.69 to 0.79 for radiographers). Thirty-five readers participated in study 2. Sensitivity was improved in the prompted condition (0.81 from 0.78) but the difference was slightly below the threshold for statistical significance (95% CI for the difference -0.003 to 0.064). Specificity also improved (0.87 from 0.86); again, the difference was not significant at 0.05 (95% CI -0.003 to 0.034). A cost-effectiveness analysis showed that computer prompting increases cost.

CONCLUSIONS

No significant improvement in film readers' sensitivity or specificity or gain in cost-effectiveness was established in either study. This may be due to the system's low specificity, its relatively poor sensitivity for subtle cancers or the fact the prompts cannot serve as aids to decision-making. Readers may have been better able to make use of the prompts after becoming more accustomed to working with them. Prompts may have an impact in routine use that is not detectable in an experimental setting. Although the case for CAD as an element of the NHS Breast Screening Programme is not made here, further research is required. Evaluations of new CAD tools in routine use are underway and their results should be given careful attention.

Assessing the impact of CAD on the sensitivity and specificity of film readers

AIM

To assess the impact of computer-aided detection (CAD) prompts on film readers' sensitivity and specificity.

MATERIAL AND METHODS

Thirty-five readers read 120 films, including 44 cancers, 40 of which were prompted. All readers looked at all cases with and without prompts. The sensitivity and specificity were calculated for each reader under each condition.

RESULTS

The sensitivity improved when CAD prompts were used (0.80 from 0.77). The difference was slightly below the threshold for statistical significance (95% CI for the difference is -0.0027-0.064). The specificity also improved (0.86 from 0.85), but not significantly. There was a significant improvement in sensitivity when readers' judgements were combined to simulate double reading, from 0.77 to 0.81. (95% CI for the difference is 0.014-0.077).

CONCLUSIONS

Analysis of prompted cancers that readers did and did not recall, found that cases were more likely to be correctly recalled if there were emphasized prompts, more prompts or if the case was harder. There was no statistically significant effect for type of abnormality or tumour size or for the performance, attitude or experience of the reader.

Reproducibility of prompts in computer-aided detection (CAD) of breast cancer

AIM

We evaluated the reproducibility of prompts using the R2 ImageChecker M2000 computer-aided detection (CAD) system.

MATERIALS AND METHODS

Forty selected two-view mammograms of women with breast cancer were digitized and analysed using the ImageChecker on 10 separate occasions. The mammograms were chosen to provide both straightforward and subtle signs of malignancy. Data analysed included mammographic abnormality, pathology, and whether the cancer was prompted or given an emphasized prompt.

RESULTS

Correct prompts were generated in 86 out of 100 occasions for screen-detected cancers. Reproducibility was less in the other categories of more subtle cancers: 21% for cancers previously missed by CAD, a group that contained more grade 1 and small (<10 mm) tumours. Prompts for calcifications were more reproducible than those for masses (76% versus 53%) and these cancers were more likely to have an emphasized prompt.

CONCLUSIONS

Probably the most important cause of variability of prompts is shifts in film position between sequential digitizations. Consequently subtle lesions that are only just above the threshold for display may not be prompted on repeat scanning. However, users of CAD should be aware that even emphasized prompts are not consistently reproducible.

The diagnostic contribution of the frontal lumbar spine radiograph in community referred low back pain--a prospective study of 1030 patients

AIM

The diagnostic contribution of the anteroposterior (AP) view was studied to assess whether this view could be omitted safely, thus reducing the radiation burden received by patients undergoing lumbar spine radiography.

MATERIALS AND METHODS

Prospective analysis of 1030 consecutive referrals for lumbar spine radiography from general practice.

RESULTS

In the majority of cases (90.5%) the AP view was non-contributory. In 4.2% the diagnosis was strengthened and it was altered in 4.6%. However, in the latter group only 1.3% of the total were considered significant alterations. These were cases of possible, but not definite, pars defects and sacroiliitis. Specific important conditions such as infection, malignancy and benign tumours were not missed on the lateral view alone, in our study population. The radiation burden is reduced by 75% by omitting the AP view.

CONCLUSION

A single lateral view is an adequate examination, with the proviso that sacroiliac joint disease is not assessed on this view and some pars defects and facet joint degenerative changes may be overlooked. The radiation protection gains are considerable. A single lateral lumbar view is now our routine practice unless sacroiliitis is a specific clinical concern.

Vitamin D receptor gene polymorphisms are associated with breast cancer risk in a UK Caucasian population

There is increasing evidence that vitamin D can protect against breast cancer. The actions of vitamin D are mediated via the vitamin D receptor (VDR). We have investigated whether polymorphisms in the VDR gene are associated with altered breast cancer risk in a UK Caucasian population. We recruited 241 women following a negative screening mammogram and 181 women with known breast cancer. The VDR polymorphism Bsm I, an intronic 3' gene variant, was significantly associated with increased breast cancer risk: odds ratio bb vs BB genotype = 2.32 (95% CI, 1.23-4.39). The Bsm I polymorphism was in linkage disequilibrium with a candidate translational control site, the variable length poly (A) sequence in the 3' untranslated region. Thus, the 'L' poly (A) variant was also associated with a similar breast cancer risk. A 5' VDR gene variant, Fok I, was not associated with breast cancer risk. Further investigations into the mechanisms of interactions of the VDR with other environmental and/or genetic influences to alter breast cancer risk may lead to a new understanding of the role of vitamin D in the control of cellular and developmental pathways.

Impact of follow up letters on non-attenders for breast screening: a general practice based study

OBJECTIVE

To determine the effectiveness of follow up letters to non-attenders for screening on the breast screening uptake in practices with a low preliminary uptake of screening.

DESIGN

Observational study of two groups of general practices. In 40 of these practices, the preliminary uptake of screening was less than 60%. These 40 practices were offered help from a clerical officer to check names and addresses of non-attenders, and to send non-attenders a reminder letter.

SETTING

93 general practices in South West London in 1995-96.

MAIN OUTCOME MEASURES

Preliminary and final uptake of breast screening.

RESULTS

Breast screening uptake increased by an average of 4.6% in the 40 intervention practices compared with 1.6% in the 53 control practices (difference 3.0%, P < 0.0001). However, the absolute increase in the uptake of screening in the intervention group was small (from 53.8% to 58.5%). The marginal cost for each additional women screened was Pounds 7 (compared with an average cost for each women screened of Pounds 27).

CONCLUSIONS

Reminder letters can help increase the uptake of screening in practices with a low preliminary uptake of breast screening. However, they have a limited role in improving the uptake of breast screening in inner city areas, and other methods of increasing uptake therefore need to be developed and evaluated.

The use of ultrasound for monitoring breast tumour response to pro-adjuvant therapy

In a prospective study, use of serial ultrasound (US) for monitoring tumour response to pro-adjuvant chemotherapy was assessed in 16 patients. Comparison was made with mammographic and pathological tumour size measurements. Clinical and radiological response to treatment was assessed using UICC (International Union Against Cancer) criteria. Comparison of clinical and US response to treatment showed some agreement in 60% and disagreement in 40%. This was comparable with clinical versus mammographic responses (55% and 45%). Correlation between calliper and pathological measurement was similar to that between US and pathological measurement (r = 0.51, P = 0.05; r = 0.50, P < 0.05). Mammography showed poorer correlation (NS). For assessment of final tumour size, US clinical measurements were comparable and better than mammography. US may be a useful tool in monitoring the response of breast tumours to pro-adjuvant therapy.

Do general practitioners influence the uptake of breast cancer screening?

OBJECTIVES

To investigate the relative importance of patient and general practice characteristics in explaining variations between practices in the uptake of breast cancer screening.

DESIGN

Ecological study examining variations in breast cancer screening rates among 131 general practices using routine data.

SETTING

Merton, Sutton, and Wandsworth Family Health Services Authority, which covers parts of inner and outer London.

MAIN OUTCOME MEASURE

Percentage of eligible women aged 50-64 who attended for mammography during the first round of screening for breast cancer (1991-1994).

RESULTS

Of the 43,063 women eligible for breast cancer screening, 25,826 (60%) attended for a mammogram. Breast cancer screening rates in individual practices varied from 12.5% to 84.5%. The estimated percentage list inflation for the practices was the variable most highly correlated with screening rates (r = -0.69). There were also strong negative correlations between screening rates and variables associated with social deprivation, such as the estimated percentage of the practice population living in households without a car (r = -0.61), and with variables that measured the ethnic make-up of practice populations, such as the estimated percentage of people in non-white ethnic groups (r = -0.60). Screening rates were significantly higher in practices with a computer than in those without (59.5% v 53.9%, difference 5.6%, 95% confidence interval 1.1 to 10.2%). There was no significant difference in screening rates between practices with and without a female partner; with and without a practice nurse; and with and without a practice manager. In a forward stepwise multiple regression model that explained 58% of the variation in breast cancer screening rates, four factors were significant independent predictors (at P = 0.05) of screening rates: list inflation and people living in households without a car were both negative predictors of screening rates, and chronic illness and the number of partners in a practice were both positive predictors of screening rates. The practice with the highest screening rate (84.5%) contacted all women invited for screening to encourage them to attend for their mammogram and achieved a rate 38% higher than predicted from the regression model. Breast cancer screening rates were on average lower than cervical cancer screening rates (mean difference 14.5%, standard deviation 12.0%) and were less strongly associated with practice characteristics.

CONCLUSIONS

The strong negative correlation between breast cancer screening rates and list inflation shows the importance of accurate age-sex registers in achieving high breast cancer screening rates. Breast cancer screening units, family health services authorities, and general practitioners need to collaborate to improve the accuracy of the age-sex registers used to generate invitations for breast cancer screening. The success of the practice with the highest screening rate suggests that practices can influence the uptake of breast cancer screening among their patients. Giving general practitioners a greater role in breast cancer screening, either by offering them financial incentives or by giving them clerical support to check prior notification lists and contact nonattenders, may also help to increase breast cancer screening rates.

Ductal carcinoma in situ presenting as a stellate lesion on mammography

Ductal carcinoma in situ (DCIS) usually manifests as microcalcification on mammography, but several other unusual forms of presentation on mammography are also described. One such atypical appearance is the stellate mass without calcification. This may occur with DCIS alone or when DCIS is associated with a complex sclerosing lesion (CSL). We retrospectively analysed the histopathological specimens and mammograms of women who were referred for biopsy from two large breast screening programmes, and were found to have DCIS as the dominant histological lesion. Of 677 women referred for surgical biopsy, 86 (13%) showed histological evidence of DCIS as the predominant lesion, and of these, seven (8%) showed a stellate appearance on mammography without associated calcification. In three cases the mammographic appearance was due to DCIS alone, and four were due to a CSL with associated DCIS. Only one case showed microinvasion (< 1 mm), and this was not large enough to account for the stellate lesion. We advocate biopsy of all radial lesions which are not surgical scars, as malignancy associated with benign lesions such as CSLs could be missed by cytological sampling errors.

Current working practices during pregnancy in British radiologists

A postal survey was conducted of female radiologists practising in the United Kingdom to assess attitudes to, and working practices during, pregnancy in radiologists. A wide variation was found in both practices and attitudes but with a good general appreciation of the principles of radiation protection. The risk to the fetus of occupational exposure during pregnancy is likely to be small but there is a widespread desire for more guidance on suitable and safe working practices for pregnant radiologists.

CT monitoring of therapy for meconium ileus

Meconium ileus equivalent is a common complication of cystic fibrosis in the postneonatal period. Because of the added risks of surgery in these patients, conservative management is preferred. We describe here a method of monitoring the conservative treatment of this condition using CT and suggest that its application will reduce the need for potentially dangerous surgical intervention.

The use of real-time orbital ultrasound in Graves' ophthalmopathy: a comparison with computed tomography

Evaluation of the severity of orbital involvement and likelihood of the development of optic neuropathy in Graves' disease can be clinically difficult. We describe the use of real-time orbital ultrasound scanning to measure the medial rectus muscle width in 20 patients with Graves' ophthalmopathy and 21 normal individuals. The normal reference interval (to 2 SDs) was 1.75 to 4.07 mm. Significantly (p less than 0.001; Mann Whitney U-test) larger values were observed in the patients compared with controls, and there was good correlation between medial rectus width and a clinical index of disease severity in individual eyes (p less than 0.001; Spearman rank correlation coefficient). Comparison of the medial rectus measurements obtained using orbital computed tomography and ultrasound showed positive correlation at the p less than 0.001 significance level. Computed tomographic medial rectus measurements also correlated with horizontal and vertical muscle indices for that orbit. We suggest that real-time ultrasound of medial rectus width, using widely available equipment, provides an accurate, simple and non-invasive means of evaluating the orbits of patients with Graves' disease. Repeated measurements may be of value in identifying patients at high risk of visual failure, and in following prospectively the orbital response to therapy in patients with Graves' ophthalmopathy.

Once daily timolol in the prophylaxis of angina pectoris

The clinical efficacy of timolol given once and twice daily was compared in the management of angina pectoris. Following a 2-week entry period, 16 normotensive male subjects with stable angina and proven myocardial ischaemia received timolol 10 mg twice daily, or 20 mg every morning for 1 month followed by 1 month on crossover therapy. All were exercised on separate days in random order 1 hr after administration of 10 mg, 1 hr after administration of 20 mg, 13 hr after administration of 10 mg and 25 hr after administration of 20 mg. In spite of significant differences in the maximum heart rates, rate pressure products and maximum lateral ST segment depression between the once and twice daily regimes, the maximal walking times were not significantly different (P greater than 0.10) and attack rates for angina and trinitrin consumption were similar (P greater than 0.45; P greater than 0.05). This evidence suggests that timolol is as effective in dosage of 20 mg taken once daily as half the dose taken twice daily in the symptom management of angina pectoris.