A comparison of five methods of measuring mammographic density: a case-control study

BACKGROUND

High mammographic density is associated with both risk of cancers being missed at mammography, and increased risk of developing breast cancer. Stratification of breast cancer prevention and screening requires mammographic density measures predictive of cancer. This study compares five mammographic density measures to determine the association with subsequent diagnosis of breast cancer and the presence of breast cancer at screening.

METHODS

Women participating in the "Predicting Risk Of Cancer At Screening" (PROCAS) study, a study of cancer risk, completed questionnaires to provide personal information to enable computation of the Tyrer-Cuzick risk score. Mammographic density was assessed by visual analogue scale (VAS), thresholding (Cumulus) and fully-automated methods (Densitas, Quantra, Volpara) in contralateral breasts of 366 women with unilateral breast cancer (cases) detected at screening on entry to the study (Cumulus 311/366) and in 338 women with cancer detected subsequently. Three controls per case were matched using age, body mass index category, hormone replacement therapy use and menopausal status. Odds ratios (OR) between the highest and lowest quintile, based on the density distribution in controls, for each density measure were estimated by conditional logistic regression, adjusting for classic risk factors.

RESULTS

The strongest predictor of screen-detected cancer at study entry was VAS, OR 4.37 (95% CI 2.72-7.03) in the highest vs lowest quintile of percent density after adjustment for classical risk factors. Volpara, Densitas and Cumulus gave ORs for the highest vs lowest quintile of 2.42 (95% CI 1.56-3.78), 2.17 (95% CI 1.41-3.33) and 2.12 (95% CI 1.30-3.45), respectively. Quantra was not significantly associated with breast cancer (OR 1.02, 95% CI 0.67-1.54). Similar results were found for subsequent cancers, with ORs of 4.48 (95% CI 2.79-7.18), 2.87 (95% CI 1.77-4.64) and 2.34 (95% CI 1.50-3.68) in highest vs lowest quintiles of VAS, Volpara and Densitas, respectively. Quantra gave an OR in the highest vs lowest quintile of 1.32 (95% CI 0.85-2.05).

CONCLUSIONS

Visual density assessment demonstrated a strong relationship with cancer, despite known inter-observer variability; however, it is impractical for population-based screening. Percentage density measured by Volpara and Densitas also had a strong association with breast cancer risk, amongst the automated measures evaluated, providing practical automated methods for risk stratification.

Breast cancer risk feedback to women in the UK NHS breast screening population

INTRODUCTION

There are widespread moves to develop risk-stratified approaches to population-based breast screening. The public needs to favour receiving breast cancer risk information, which ideally should produce no detrimental effects. This study investigates risk perception, the proportion wishing to know their 10-year risk and whether subsequent screening attendance is affected.

METHODS

Fifty thousand women attending the NHS Breast Screening Programme completed a risk assessment questionnaire. Ten-year breast cancer risks were estimated using a validated algorithm (Tyrer-Cuzick) adjusted for visually assessed mammographic density. Women at high risk (⩾8%) and low risk (<1%) were invited for face-to-face or telephone risk feedback and counselling.

RESULTS

Of those invited to receive risk feedback, more high-risk women, 500 out of 673 (74.3%), opted to receive a consultation than low-risk women, 106 out of 193 (54.9%) (P<0.001). Women at high risk were significantly more likely to perceive their risk as high (P<0.001) and to attend their subsequent mammogram (94.4%) compared with low-risk women (84.2%; P=0.04) and all attendees (84.3%; ⩽0.0001).

CONCLUSIONS

Population-based assessment of breast cancer risk is feasible. The majority of women wished to receive risk information. Perception of general population breast cancer risk is poor. There were no apparent adverse effects on screening attendance for high-risk women whose subsequent screening attendance was increased.

Mammographic density adds accuracy to both the Tyrer-Cuzick and Gail breast cancer risk models in a prospective UK screening cohort

INTRODUCTION

The Predicting Risk of Cancer at Screening study in Manchester, UK, is a prospective study of breast cancer risk estimation. It was designed to assess whether mammographic density may help in refinement of breast cancer risk estimation using either the Gail model (Breast Cancer Risk Assessment Tool) or the Tyrer-Cuzick model (International Breast Intervention Study model).

METHODS

Mammographic density was measured at entry as a percentage visual assessment, adjusted for age and body mass index. Tyrer-Cuzick and Gail 10-year risks were based on a questionnaire completed contemporaneously. Breast cancers were identified at the entry screen or shortly thereafter. The contribution of density to risk models was assessed using odds ratios (ORs) with profile likelihood confidence intervals (CIs) and area under the receiver operating characteristic curve (AUC). The calibration of predicted ORs was estimated as a percentage [(observed vs expected (O/E)] from logistic regression.

RESULTS

The analysis included 50,628 women aged 47-73 years who were recruited between October 2009 and September 2013. Of these, 697 had breast cancer diagnosed after enrolment. Median follow-up was 3.2 years. Breast density [interquartile range odds ratio (IQR-OR) 1.48, 95 % CI 1.34-1.63, AUC 0.59] was a slightly stronger univariate risk factor than the Tyrer-Cuzick model [IQR-OR 1.36 (95 % CI 1.25-1.48), O/E 60 % (95 % CI 44-74), AUC 0.57] or the Gail model [IQR-OR 1.22 (95 % CI 1.12-1.33), O/E 46 % (95 % CI 26-65 %), AUC 0.55]. It continued to add information after allowing for Tyrer-Cuzick [IQR-OR 1.47 (95 % CI 1.33-1.62), combined AUC 0.61] or Gail [IQR-OR 1.45 (95 % CI 1.32-1.60), combined AUC 0.59].

CONCLUSIONS

Breast density may be usefully combined with the Tyrer-Cuzick model or the Gail model.

Digital breast tomosynthesis at screening assessment: are two views always necessary?

OBJECTIVE

The current recommendation from the UK National Health Service Breast Screening Programme is that digital breast tomosynthesis (DBT) can be used for further assessment of possible screen-detected soft-tissue abnormalities in place of spot compression views and when used should be performed in two projections. The aim of the study was to assess whether two-view DBT is necessary if the abnormality is seen only in one view on initial full-field digital mammography (FFDM).

METHODS

617 cases with possible masses, distortions and asymmetrical densities visualized only in one view on screening FFDM were included. All of these females underwent two-view DBT, clinical examination and ultrasound. The FFDM and DBT findings on each view were compared and correlated with the histological diagnosis.

RESULTS

586 of 617 cases had normal or benign findings on further assessment, and no additional information was obtained on the other DBT view. There were 31 confirmed cancers. In 26 cases (84%), the cancer was seen on the corresponding DBT view. No cancer was seen on the other DBT view alone. Five cancers (16%) were not seen on either view on DBT owing to technical reasons. No cancers would have been missed if only the corresponding DBT view was performed.

CONCLUSION

Two-view DBT may not be necessary when used for further assessment of possible screen-detected soft-tissue abnormalities. Larger studies should be undertaken to investigate this further.

ADVANCES IN KNOWLEDGE

One-view DBT may be adequate in assessing soft-tissue abnormalities seen only on one FFDM view.

Abstract P5-12-01: Predicting the effect of tamoxifen on the breast: Change in measures of breast density, serum markers and SNPs

Body: Introduction In the IBIS I Prevention Trial we demonstrated that tamoxifen prevented breast cancer in women with greater than 9 % absolute reduction in visually assessed mammographic density over a 12-18 month period as assessed by an expert radiologist, RW (1). In this study we investigated: whether RW obtained similar results in a different group of women treated with tamoxifen; how other expert mammographic film readers with experience of density assessment (radiologists, advanced practitioner radiographers and a breast physician) estimated mammographic change; how visual change relates to change in automated measures of volumetric density; and whether we can predict change by serum markers or SNPs. Methods 105 women aged 33 to 46 at greater than 1 in 6 lifetime breast cancer risk completed one year’s treatment with tamoxifen. RW assessed mammographic percentage density in increments of 5% for baseline and one year mammograms. Two or three of a pool of eight readers estimated % density using a visual analogue scale (VAS). Percent change was also estimated using a computer-assisted thresholding technique (Cumulus). Change in volume of dense tissue (Quantra™ & Volpara™) was measured. Changes in lipids, IGF1, insulin and relevant SNPs were measured to determine whether they predicted density change. Results. Estimates of change obtained by RW were broadly consistent with those from our previous study, as were those from Cumulus, but could not be replicated using estimates from the pooled results of VAS readers. Tamoxifen was associated with marked reductions of dense volume of the breast (Table 1) However the different methods were at best only moderately correlated with RW (r less than 0.6). Change in serum triglycerides significantly predicted density change as measured by RW but none of the other serum measures or SNPs did.

Table 1 Numbers of women and percentage change in density measures after one year of tamoxifen% Density changeRW %changeOther radiologists %changeCumulus %change_____% Dense volume change^Quantra %changeVolpara %change40+001 40+15930+503 30+141020+12013 20+202010+35630 10+17260+498143 0+16190-4188 0-1615Number10510598  9899RW = Ruth Warren. CUMULUS was measured by JS, a trained operator of the software. * Percentage point change eg if density changed from 40% to 30% this was regarded as a 10% change.^ Reduction in dense volume expressed as a percentage of baseline dense volume. We used Quantra version 2.0 and Volpara version 1.4.5

Conclusions Whilst RW remained consistent with previous density estimation it was not possible to use a pool of other expert readers to predict change. Cumulus gave similar results to RW but is difficult to use in practice. There was good agreement between the two objective volumetric measures used (r=0.5) and since these are automated they may be suitable for clinical practice. However their relationship to the long term breast cancer preventative effect of tamoxifen needs to be established.

Reference 1 Tamoxifen-induced reduction in mammographic density and breast cancer risk reduction: a nested case-control study. Cuzick J, Warwick J, Pinney E, Duffy JW, Cawthorn S, Howell A, Forbes JF, Warren RM. J Natl Cancer Inst. 2011 May 4; 103 (9): 744-52.

Citation Format: Anthony Howell, Sue Astley, Elaine Harkness, Julia Wiseman, Jill Fox, Paula Stavrinos, Mary Wilson, Yit Lim, Valerie Reece, Ursula Beetles, Anil Jain, Jamie Sergeant, Jack Cuzick, Ruth Warren, Gareth Evans. Predicting the effect of tamoxifen on the breast: Change in measures of breast density, serum markers and SNPs [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P5-12-01.

Assessing individual breast cancer risk within the U.K. National Health Service Breast Screening Program: a new paradigm for cancer prevention

The aim of this study is to determine breast cancer risk at mammographic screening episodes and integrate standard risk factors with mammographic density and genetic data to assess changing the screening interval based on risk and offer women at high risk preventive strategies. We report our experience of assessing breast cancer risk within the U.K. National Health Service Breast Screening Program using results from the first 10,000 women entered into the "Predicting Risk Of breast Cancer At Screening" study. Of the first 28,849 women attending for screening at fifteen sites in Manchester 10,000 (35%) consented to study entry and completed the questionnaire. The median 10-year Tyrer-Cuzick breast cancer risk was 2.65% (interquartile range, 2.10-3.45). A total of 107 women (1.07%) had 10-year risks 8% or higher (high breast cancer risk), with a further 8.20% having moderately increased risk (5%-8%). Mammographic density (percent dense area) was 60% or more in 8.3% of women. We collected saliva samples from 478 women for genetic analysis and will extend this to 18% of participants. At time of consent to the study, 95.0% of women indicated they wished to know their risk. Women with a 10-year risk of 8% or more or 5% to 8% and mammographic density of 60% or higher were invited to attend or be telephoned to receive risk counseling; 81.9% of those wishing to know their risk have received risk counseling and 85.7% of these were found to be eligible for a risk-reducing intervention. These results confirm the feasibility of determining breast cancer risk and acting on the information in the context of population-based mammographic screening.

Prevention of breast cancer in the context of a national breast screening programme

Breast cancer is not only increasing in the west but also particularly rapidly in eastern countries where traditionally the incidence has been low. The rise in incidence is mainly related to changes in reproductive patterns and lifestyle. These trends could potentially be reversed by defining women at greatest risk and offering appropriate preventive measures. A model for this approach was the establishment of Family History Clinics (FHCs), which have resulted in improved survival in younger women at high risk. New predictive models of risk that include reproductive and lifestyle factors, mammographic density and measurement of risk-associated single nucleotide polymorphisms (SNPs) may give more precise information concerning risk and enable better targeting for mammographic screening programmes and of preventive measures. Endocrine prevention using anti-oestrogens and aromatase inhibitors is effective, and observational studies suggest lifestyle modification may also be effective. However, referral to FHCs is opportunistic and predominantly includes younger women. A better approach for identifying older women at risk may be to use national breast screening programmes. Here were described pilot studies to assess whether the routine assessment of breast cancer risk is feasible within a population-based screening programme, whether the feedback and advice on risk-reducing interventions would be welcomed and taken up, and to consider whether the screening interval should be modified according to breast cancer risk.

P4-11-07: Feasibility and Acceptability of Offering Breast Cancer Risk Estimation in the Context of the UK National Health Service Breast Cancer Screening Programme: A New Paradigm for Cancer Prevention

Background: Currently there are no real attempts internationally to tailor breast screening programmes to individual risk Methods: We have assessed the feasibility of collecting breast cancer risk information during routine mammographic screening in the National Health Service Breast Screening Programme (NHSBSP) in England, in order to consider, ultimately, adapting the screening interval to risk of breast cancer and introducing preventive strategies in women at high risk. The study Predicting Risk Of Cancer At Screening (PROCAS) aims to recruit 60,000 women over 3 years. Results: 26,000 women (June 8th 2011) have so far given consent to join the study. Thirty six percent of the first 20,000 women in nineteen screening sites in Manchester consented to enter the study and completed a risk factor questionnaire. The median 10 year breast cancer risk was 2.65%, with 926 (9.26%) of the first 10,000 women having a 10 year risk of ≥5% and 92 (0.92%) having a 10 year risk of ≥8% (Tyrer-Cuzick), IQR:1.35. 832 (8.32%) women had a mammographic density of 60% or greater (Visual Analogue Scale). We collected saliva samples from 1019 women for genetic analysis and will extend this to 18% of participants. Of those who agreed to participate in the study, 94% indicated that they wished to know their breast cancer risk. Women with a 10-year risk of ≥8%, and women with a 10-year risk of ≥5% and mammographic density ≥60% were invited to attend or be telephoned to be counselled. To date 138 have accepted with 135, so far, having received risk counselling. Nineteen percent of the high-risk women identified subsequently decided to enter a randomised breast cancer prevention study with either a dietary or drug intervention (IBIS2, anastrazole vs placebo). Results from the first 1,000 women who provided DNA samples suggest that the risk information from the 18 validated SNPS may enhance existing risk models. Conclusion: This study demonstrates that it is feasible to determine individual breast cancer risk and offer women appropriate risk-reducing interventions within the context of a population-based mammographic screening programme.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-11-07.

Value of axillary ultrasound and cytology in assessing nodal status preoperatively

Abstract #1007

Preoperative identification of axillary node involvement in early breast cancer allows correct surgical procedures to be performed and avoids second axillary operations. We compared preoperative axillary assessment using ultrasound ± cytology with the eventual histopathological results to identify the accuracy of preoperative axillary node assessment.&#x2028; Methods: Preoperative axillary ultrasound was used to identify the presence of suspicious or malignant nodes which were then confirmed with cytological assessment to allow management decisions regarding axillary clearance (or sentinel node biopsy (SNB) if nodes appeared negative).&#x2028; Results: Overall 79/365 (21%) early breast cancer patients had suspicious or malignant nodes on ultrasound, of which 78 were confirmed on cytology, thus avoiding an unnecessary SNB operation in these patients. Ultrasound and cytology accurately identified patients with ER negative (P=≤0.001), high grade (P=≤0.001) and large size tumours ≤20mm (P=≤0.001), with involved nodes. Only 11% ER negative compared to 46% ER positive tumours were incorrectly classified (P=0.002). In contrast ER positive, low grade, small tumours were most likely to have a false negative axillary assessment. Specificity of cytological assessment of nodes was 99% and sensitivity 54%.&#x2028; Conclusions: Axillary ultrasound combined with cytological assessment of suspicious nodes accurately identifies majority of women who require axillary clearance.&#x2028; &#x2028;

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1007.