Detection of Bilateral Breast Cancer at Biennial Screening Mammography in the Netherlands: A Population-based Study

Clinical characteristics and the associated risk factors of the development of bilateral breast cancers: A case-control study

Background

The clinical impacts of bilateralism on prognosis and clinical decision-making remain contradictory particularly in areas with low incidence and delayed diagnosis of primary breast cancer. Identification of women at risk of bilateral breast cancer is required to improve patient management and to design the appropriate surveillance.

Methods

A total of 1083 women were enrolled and analyzed for the presence of synchronous and metachronous bilateral breast cancer as cases and unilateral breast cancer as controls during the median follow-up of 4.8 years.

Results

The incidence of bilateral breast cancer was 7.5% (81 of 1083). In comparison with unilateral breast cancers, bilateral cases were significantly diagnosed in younger women (P = 0.037, mean age was 35.6 years) who had a larger tumor size (P = 0.012, mean tumor size was 8 cm in diameter). Histological type of lobular cancer was identified as one of the risk factors for the development of contralateral breast cancer (OR 5.564, 95% CI: 3.219-9.620) and synchronous bilateral breast cancer (OR 2.561, 95% CI: 1.182-5.550). Bilateral breast cancer had significantly shorter progression-free survival (Mean survival was 26.6 vs 52.5 months for bilateral and unilateral breast cancers, respectively; P = 0.001) and shorter time to develop distant metastasis (Mean survival was 41.7 vs 104 months for bilateral and unilateral breast cancers, respectively; P = 0.001).

Conclusion

Patients with first primary breast tumors with lobular histological type and advanced stages were observed to have higher risks for the development of contralateral breast cancers.

Frequency and diagnostic outcome of bilateral recall at screening mammography

Our study was performed to determine the frequency of recall for bilateral breast lesions at screening mammography and compare its outcome with respect to unilateral recall. We included 329 132 screening mammograms (34 889 initial screens and 294 243 subsequent screens) from a Dutch screening mammography program between January 2013 and January 2018. During a 2‐year follow‐up, we collected radiological data, pathology reports and surgical reports of all recalled women. At bilateral recall, the lesion with the highest Breast Imaging Reporting and Data System score was used as the index lesion when comparing screening mammography characteristics at bilateral vs unilateral recall. A total of 9806 women were recalled at screening (recall rate, 3.0%). Bilateral recall comprised 2.8% (271/9806) of all recalls. Biopsy was more frequently performed after bilateral recall than unilateral recall (54.6% [148/271] vs 44.1% [4201/9535], P < .001), yielding a lower positive predictive value (PPV) of biopsy after bilateral recall (42.6% vs 51.7%, P = .029). The PPV of recall was comparable for both groups (23.2% [63/271] vs 22.8% [2173/9535], P = .85). Invasive cancers after bilateral recall were larger than those diagnosed after unilateral recall (P = .02), but histological subtype, histologic grading, receptor status and proportions of lymph node positive cancers were comparable. Bilateral recall infrequently occurs at screening mammography. Biopsy is more frequently performed following bilateral recall, but the PPV of recall is similar for unilateral and bilateral recall. Invasive cancers of both groups show comparable pathological features except of a larger tumor size after bilateral recall.

What's new?

Data on bilateral breast cancer in a screened population is sparse, and information on bilateral recall is lacking. Based on more than 329,000 screening mammograms, our study shows that bilateral recall occurs infrequently at screening mammography, and that the majority of these recalls are false positives. Invasive cancer has comparable pathological features in bilateral and unilateral breast cancer patients, except larger tumour size after bilateral recall. Altogether, the results highlight the need for screening radiologists to pay vigorous attention to the contralateral breast after detecting a screening mammographic abnormality in order to facilitate a timely diagnosis of bilateral breast cancer.

Delayed breast cancer diagnosis after repeated recall at biennial screening mammography: an observational follow-up study from the Netherlands

Background

Delay in detection of breast cancer may worsen tumour characteristics, with progression of tumour size and a higher risk of metastatic lymph nodes. The purpose of this study was to investigate delayed breast cancer diagnosis after repeated recall for the same mammographic abnormality at screening.

Methods

This was a retrospective study performed in two cohorts of women enrolled in a mammography screening programme in the Netherlands. All women aged 50−75 who underwent biennial screening mammography either between January 1, 1997 and December 31, 2006 (cohort 1) or between January 1, 2007 and December 31, 2016 (cohort 2) were included.

Results

The cohorts showed no difference in proportions of women with delayed breast cancer diagnosis of at least 2 years (2.2% versus 2.8%, P = 0.29). Most delays were caused by incorrect BI-RADS classifications after recall (74.2%). An increase in mean tumour size was seen when comparing sizes at initial false-negative recall and at diagnosis of breast cancer (P < 0.001).

Conclusions

The proportion of women with a long delay in breast cancer confirmation following repeated recall at screening mammography has not decreased during 20 years of screening. These delays lead to larger tumour size at detection and may negatively influence prognosis.

Characterization of Breast Microcalcifications Using a New Ultrasound Image-Processing Technique

OBJECTIVES

To evaluate a new commercial image-processing technique (MicroPure; Toshiba America Medical Systems, Tustin, CA) for detection and characterization of breast microcalcifications in patients undergoing stereotactic or ultrasound-guided biopsies using mammography as the reference standard.

METHODS

One hundred female patients, with a total of 104 lesions, scheduled for an image-guided biopsy of an area with breast microcalcifications (identified on a prior mammogram) underwent MicroPure examinations of the breast using an Aplio XG scanner (Toshiba America Medical Systems) with a broad-bandwidth linear array. MicroPure combines nonlinear imaging and speckle suppression to mark suspected calcifications as white spots in a blue overlay image. Four independent and blinded readers (2 radiologists and 2 physicists) analyzed 208 digital clips consisting of dual grayscale ultrasound and MicroPure imaging, counting the number of microcalcifications seen with MicroPure. The observers also assessed the level of suspicion on a qualitative, visual analog, 6-point scale from 0 (no findings) over 1 (benign) to 5 (malignant).

RESULTS

The mean number of microcalcifications ± SD seen was 6.3 ± 3.5, whereas mammography saw 28.9 ± 24.6 (P = .66). When the MicroPure level of suspicion scores were compared with pathologic results using a receiver operating characteristic curve analysis, the areas under the curve ranged from 0.54 to 0.59. Nonetheless, malignant cases were seen to have significantly more microcalcifications than benign cases (mean number of microcalcifications, 6.9 ± 5.1 versus 5.3 ± 3.7; P = .02).

CONCLUSIONS

MicroPure can be used to identify areas with breast microcalcifications but cannot effectively characterize such areas. Instead, MicroPure may represent a new imaging method for guiding a biopsy to areas of microcalcifications.

Ultrasound Detection of Microcalcifications in Surgical Breast Specimens

The objective was to evaluate a commercial image processing technique (MicroPure, Canon Medical Systems, Tustin, CA, USA) for detection of microcalcifications in breast surgical specimens. Twenty women scheduled for surgical excision of an area with breast calcifications were enrolled, their surgical specimens underwent grayscale ultrasound (US) and MicroPure examination using an Aplio XG scanner (Canon). Four independent and blinded readers analyzed 54 US and 54 MicroPure digital clips to determine the number of calcifications and scored image quality and artifacts on a 10-point scale. All readers saw significantly more microcalcifications with MicroPure than with US, 14.0 ± 12.0 versus 3.0 ± 3.2 (p <0.0001). Three readers preferred MicroPure image quality over that of US (p <0.009) and vice versa for one reader (p = 0.003). Three readers saw fewer Cooper's ligament artifacts with MicroPure than with US (p <0.0001); one reader saw no significance difference between them (p = 0.58). In conclusion MicroPure identified more breast microcalcifications than grayscale US in ex vivo surgical breast specimens.

Frequency and characteristics of contralateral breast abnormalities following recall at screening mammography

PURPOSE

To determine the frequency and characteristics of contralateral, non-recalled breast abnormalities following recall at screening mammography.

METHODS

We included a series of 130,338 screening mammograms performed between 1 January 2014 and 1 January 2016. During the 1-year follow-up, clinical data were collected for all recalls. Screening outcome was determined for recalled women with or without evaluation of contralateral breast abnormalities.

RESULTS

Of 3,995 recalls (recall rate 3.1%), 129 women (3.2%) underwent assessment of a contralateral, non-recalled breast abnormality. Most lesions were detected at clinical mammography and/or breast tomosynthesis (101 women, 78.3%). The biopsy rate was similar for recalled lesions and contralateral, non-recalled lesions, but the positive predictive value of biopsy was higher for recalled lesions (p = 0.01). A comparable proportion of the recalled lesions and contralateral, non-recalled lesions were malignant (p = 0.1). The proportion of ductal carcinoma in situ was similar for both groups, as well as invasive cancer characteristics and type of surgical treatment.

CONCLUSIONS

About 3% of recalled women underwent evaluation of contralateral, non-recalled breast lesions. Evaluation of the contralateral breast after recall is important as we found that 15.5% of contralateral, non-recalled lesions were malignant. Contralateral cancers and screen-detected cancers show similar characteristics, stage and surgical treatment.

KEY POINTS

• 3% of recalled women underwent evaluation of contralateral, non-recalled lesions • One out of seven contralateral, non-recalled lesions was malignant • A contralateral cancer was diagnosed in 0.5% of recalls • Screen-detected cancers and non-recalled, contralateral cancers showed similar histological characteristics • Tumour stage and surgical treatment were similar for both groups.

Inferior survival for young patients with contralateral compared to unilateral breast cancer: a nationwide population-based study in the Netherlands

To compare overall survival between women with unilateral breast cancer (UBC) and contralateral breast cancer (CBC). Women with UBC (N = 182,562; 95 %) and CBC (N = 8,912; 5 %) recorded in the Netherlands Cancer Registry between 1989 and 2008 were included and followed until 2010. We incorporated CBC as a time-dependent covariate to compute the overall mortality rate ratio between women with CBC and UBC. Prognostic factors for overall death were examined according to age at first breast cancer. Women with CBC exhibited a 30 % increase in overall mortality (Hazard Ratio (HR), 95 % Confidence Interval: 1.3, 1.3-1.4) compared with UBC, decreasing with rising age at diagnosis of first breast cancer (<50 years: 2.3, 2.2-2.5 vs. ≥70 years: 1.1, 1.0-1.1). Women older than 50 years at CBC diagnosis and diagnosed 2-5 years after their first breast cancer exhibited a 20 % higher death risk (1.2, 1.0-1.3) compared to those diagnosed within the first 2 years. In women younger than 50 years, the HR was significantly lower if the CBC was diagnosed >5 years after the first breast cancer (0.7, 0.5-0.9). The prognosis for women with CBC significantly improved over time (2004-2008: 0.6, 0.5-0.7 vs. 1989-1993). Women with CBC had a lower survival compared to women with UBC, especially those younger than 50 years at first breast cancer diagnosis. A tailored follow-up strategy beyond current recommendations is needed for these patients who, because of their age and absence of known familial risk, are currently not invited for population-based screening.

Characteristics and screening outcome of women referred twice at screening mammography

OBJECTIVES

To determine the characteristics and screening outcome of women referred twice at screening mammography.

METHODS

We included 424,703 consecutive screening mammograms and collected imaging, biopsy and surgery reports of women with screen-detected breast cancer. Review of screening mammograms was performed to determine whether or not an initial and second referral comprised the same lesion.

RESULTS

The overall positive predictive value of referral for cancer was 38.6% (95% CI 37.3-39.8%). Of 147 (2.6%) women referred twice, 86 had been referred for a different lesion at second referral and 32 of these proved malignant (37.2%, 95% CI 27.0-47.4%). Sixty-one women had been referred twice for the same lesion, of which 22 proved malignant (36.1%, 95% CI 24.1-48.0%). Characteristics of these women were comparable to women with cancer diagnosed after first referral. Compared with women without cancer at second referral for the same lesion, women with cancer more frequently showed suspicious densities at screening mammography (86.4% vs 53.8%, P = 0.02) and work-up at first referral had less frequently included biopsy (22.7% vs 61.5%, P = 0.004).

CONCLUSIONS

Cancer risk in women referred twice for the same lesion is similar to that observed in women referred once, or referred for a second time but for a different lesion.

KEY POINTS

Cancer risk was 36% for lesions referred twice at screening mammography. The cancer risk was similar for lesions referred only once at screening. Densities at first referral were associated with increased cancer risk at second referral. No biopsy at first referral was associated with increased cancer risk at second referral. Patient and tumour characteristics were similar for women with and without diagnostic delay.

New image processing technique for evaluating breast microcalcifications: a comparative study

OBJECTIVES

The purpose of this study was to evaluate a new commercial image processing technique (MicroPure; Toshiba America Medical Systems, Tustin, CA) for identifying breast microcalcifications compared to gray scale ultrasound imaging (US) using mammography as the reference standard.

METHODS

Twenty women, with breast calcifications identified mammographically, underwent gray scale US and MicroPure examinations of the breast. Still images and digital clips of the target area were acquired using gray scale US and MicroPure (at 3 different sensitivity levels: 0, 1, and 2). The images were analyzed by 4 independent and blinded readers (2 radiologists and 2 physicists) to determine the number of calcifications as well as to score image quality and artifacts.

RESULTS

For all 4 readers, there were significantly more calcifications seen with MicroPure (at the 2 highest sensitivity levels) compared to gray scale US (P < .009). Agreement between readers consistently increased from gray scale US to MicroPure imaging (gray scale intraclass correlation coefficient, 0.02-0.44; versus MicroPure intraclass correlation coefficient, 0.34-0.71). The agreement improved between mammography and MicroPure (13.2%-28.3%) when compared with mammography and gray scale US (1.7%-5.2%); the 2 radiologists saw a bigger improvement. Two readers preferred the MicroPure image quality over gray scale US (P < .001) and vice versa for the other 2 readers(P < .001). All 4 readers saw fewer artifacts with MicroPure (at level 2) than with gray scale US (P < .02).

CONCLUSIONS

MicroPure imaging identified significantly more breast microcalcifications than gray scale US.

Malpractice claims following screening mammography in The Netherlands

Although malpractice lawsuits are frequently related to a delayed breast cancer diagnosis in symptomatic patients, information on claims at European screening mammography programs is lacking. We determined the type and frequency of malpractice claims at a Dutch breast cancer screening region. We included all 85,274 women (351,009 screens) who underwent biennial screening mammography at a southern breast screening region in The Netherlands between 1997 and 2009. Two screening radiologists reviewed the screening mammograms of all screen detected cancers and interval cancers and determined whether the cancer had been missed at the previous screen or at the latest screen, respectively. We analyzed all correspondence between the screening organization, clinicians and screened women, and collected complaints and claims until September 2011. At review, 20.9% (308/1,475) of screen detected cancers and 24.3% (163/670) of interval cancers were considered to be missed at a previous screen. A total of 19 women (of which 2, 6 and 11 women had been screened between 1997 and 2001 (102,439 screens), 2001 and 2005 (114,740 screens) and 2005 and 2009 (133,830 screens), respectively) had contacted the screening organization for additional information about their screen detected cancer or interval cancer, but filed no claim. Three other women directly initiated an insurance claim for financial compensation of their interval cancer without previously having contacted the screening organization. We conclude that screening-related claims were rarely encountered, although many screen detected cancers and interval cancers had been missed at a previous screen. A small but increasing proportion of women sought additional information about their breast cancer from the screening organization.

Patient and tumor characteristics of bilateral breast cancer at screening mammography in the Netherlands, a population-based study

Few data are available on bilateral breast cancer in the screening population. The aim of this study was to determine patient and tumor characteristics of women with bilateral breast cancer at screening mammography. We included all 350,637 screening mammography examinations of women participating in a biennial screening program in a southern screening region of the Netherlands between May 1998 and January 2010. For referred women, all breast imaging reports, biopsy results, and surgery reports during one year after referral were collected. We compared patient and tumor characteristics of referred women with a diagnosis of bilateral breast cancer or unilateral breast cancer at workup. Bilateral or unilateral breast cancer had been diagnosed in respectively 40 (2.2%) and 1766 (97.8%) of 1806 referred women. Women with bilateral or unilateral breast cancer did not differ significantly in mean age, mammographic breast density, family history of breast cancer, or use of hormone replacement therapy. Compared with index cancers, contralateral cancers comprised significantly more lobular cancers (P = 0.02). Tumor size, mitotic activity, and estrogen receptor status were comparable for both groups, but contralateral cancers had a significantly lower risk of lymph node metastases (P = 0.03). Compared to unilateral breast cancer, contralateral malignancies in women with bilateral breast cancer comprised significantly more lobular cancers (P = 0.004) and lymph node negative cancers (P = 0.01). Contralateral breast cancers detected at screening comprise more lobular cancers and show less nodal involvement than index cancers or unilateral cancers. No differences are observed with respect to other patient and tumor characteristics.