Why do women refrain from mammography screening?

IntroductionBreast cancer is the leading cause of death for middle-aged women in Sweden. Approximately 600,000 women are surveyed annually within the national screening program. However, 20% of Swedish women do not participate in mammography screening. Participation in mammography screening is a complex phenomenon that has many dimensions. The aim of this study was to explore the reasons why women refrain from mammography screening from the perspective of non-attending women.MethodA qualitative approach was chosen, and 10 women were interviewed. The interviews were analysed using qualitative content analysis.ResultsTwo categories were identified: individual needs and absence of active promotion. “Non-personalized system” was the main theme that emerged from the analysis.ConclusionThe mammography screening does not adapt to the needs of each individual. This may be the reason why some women refrain from mammography screening.     

Can mechanical imaging increase the specificity of mammography screening?

Objectives

This study aimed to investigate the effects of adding adjunct mechanical imaging to mammography breast screening. We hypothesized that mechanical imaging could detect increased local pressure caused by both malignant and benign breast lesions and that a pressure threshold for malignancy could be established. The impact of this on breast screening was investigated with regard to reductions in recall and biopsy rates.

Methods

155 women recalled from breast screening were included in the study, which was approved by the regional ethical review board (dnr 2013/620). Mechanical imaging readings were acquired of the symptomatic breast. The relative mean pressure on the suspicious area (RMPA) was defined and a threshold for malignancy was established.

Results

Biopsy-proven invasive cancers had a median RMPA of 3.0 (interquartile range (IQR)?=?3.7), significantly different from biopsy-proven benign at 1.3 (IQR?=?1.0) and non-biopsied cases at 1.0 (IQR?=?1.3) (P?<?0.001). The lowest RMPA for invasive cancer was 1.4, with 23 biopsy-proven benign and 33 non-biopsied cases being below this limit. Had these women not been recalled, recall rates would have been reduced by 36% and biopsy rates by 32%.

Conclusions

If implemented in a screening situation, this may substantially lower the number of false positives.

Key Points

? Mechanical imaging is used as an adjunct to mammography in breast screening. ? A threshold pressure can be established for malignant breast cancer. ? Recalls and biopsies can be substantially reduced.

     

Routine screening mammography: how important is the radiation-risk side of the benefit-risk equation?

The potential radiation hazards associated with routine screening mammography, in terms of breast cancer induction, are discussed in the context of the potential benefits. The very low energy X-rays used in screening mammography (26-30 kVp) are expected to be more hazardous, per unit dose, than high-energy X- or gamma-rays, such as those to which A-bomb survivors (from which radiation risk estimates are derived) were exposed. Based on in vitro studies using oncogenic transformation and chromosome aberration end-points, as well as theoretical estimates, it seems likely that low doses of low-energy X-rays produce an increased risk per unit dose (compared with high energy photons) of about a factor of 2. Because of the low doses involved in screening mammography, the benefit-risk ratio for older women would still be expected to be large, though for younger women the increase in the estimated radiation risk suggests a somewhat later age than currently recommended--by about 5-10 years--at which to commence routine breast screening.     

Is maximum positive predictive value a good indicator of an optimal screening mammography practice?

OBJECTIVE: Positive predictive value (PPV1) has been used as one important indicator of the quality of screening mammography programs. We show how the relationship between sensitivity and recall rate may affect the operating point at which optimal (maximum) PPV1 occurs. CONCLUSION: Optimal (maximum) PPV1 can occur at any sensitivity level and should not be used as the sole indicator for practice optimization because it does not take into account the number of cancers that would be missed at that sensitivity.     

Analysis of interval cancers observed in an Italian mammography screening programme (2000–2006)

Purpose

The purpose of this study was to assess the interval cancer (IC) proportional incidence and review IC cases observed in an Italian mammography screening programme during 2000–2006.

Materials and methods

ICs were identified through linkage of a screening database with the local cancer registry and hospital discharge records to calculate proportional (observed/expected) incidence. Negatively reported mammograms preceding ICs underwent blind review (randomly mixed with negative controls in a 2:1 ratio) by three expert radiologists and classified according to European guidelines criteria (OC=occult, MS=minimal sign, SE=screening error) according to majority report. Proportional IC incidence and rate of reviewed IC classified as SE were compared with European guideline standards.

Results

Proportional IC incidence was 10.8% in the first and 40.0% in the second year of the interval (European standard=30% or 50%, respectively). Sensitivity estimate for the 2-year interval was 74.6%. ICs were reviewed as SE, MS or OC in 15.0%, 14.0% or 71.0% of cases, respectively. Corresponding review results for negative controls were 7.0%, 25.0% or 68.0%, respectively. Positive predictive value for IC was 51.7% for SE and 21.8% for MS reporting category, respectively (p=0.008). European standard (<20% reviewed as SE) was reached.

Conclusions

The study shows that the sensitivity of the mammography programme was good, complying with European guideline recommendations. Assessment of IC-based early indicators of screening efficacy is feasible in a current screening programme and should become a routine procedure.     

Digital mammography screening: how many breast cancers are additionally detected by bilateral ultrasound examination during assessment?

Objective

To assess the positive predictive values of incremental breast cancer detection (PPV1) in relation to the mammographic breast density and of performed biopsies (PPV3) resulting from supplemental bilateral physician-performed whole-breast ultrasound (US) at recall of a population-based digital mammography screening programme.

Methods

A total of 2,803 recalled screening participants (50–69 years), who had additional bilateral US with prospectively completed documentation [grading of breast density (ACR 1–4), biopsy recommendation related to US and mammography], were included.

Results

The PPV1 of supplemental cancer detection only by US was 0.21 % (6/2,803) compared to 13.8 % (386/2,803) by mammography. The PPV1 of US-only cancer detection was 0 %, 0.16 % (2/1,220), 0.22 % (3/1,374) and 1.06 % (1/94) for women with breast density of ACR 1, ACR 2, ACR 3 and ACR 4, respectively. The PPV3 of US-only lesion detection was 33.3 % (9/27) compared to 38.0 % (405/1,066) by mammography. The proportion of invasive cancers no larger than 10 mm was 37.5 % (3/8) for US-only detection compared to 38.4 % (113/294) for mammographic detection.

Conclusion

Bilateral ultrasound at recall, in addition to the assessment of screen-detected mammographic abnormalities, resulted in a low PPV of incremental cancer detection only by US, without a disproportional increase of false-positive biopsies.

Key Points

? Bilateral breast ultrasound was assessed in women recalled following digital mammography screening. ? Overall breast cancer detection rate reached the desired level of European guidelines. ? Additional ultrasound-only cancer detection had a low positive predictive value (0.21 %). ? Ultrasound did detect additional unexpected breast cancers in breasts graded ACR 2–4. ? Bilateral breast ultrasound offers little or only marginal benefit in routine screening.     

Utilization and cost of diagnostic imaging and biopsies following positive screening mammography in the southern breast cancer screening region of the Netherlands, 2000–2005

We prospectively assessed trends in utilization and costs of diagnostic services of screen-positive women in a biennial breast cancer screening program for women aged 50–75 years. All 2,062 women with suspicious findings at screening mammography in the southern region of the Netherlands between 1 January 2000 and 1 July 2005 (158,997 screens) were included. Data were collected on any diagnostic examinations, interventional procedures, and surgical consultations with two-year follow-up. We used national reimbursement rates to estimate imaging costs and percutaneous biopsy costs. Cost prices, charged by hospitals, were used to estimate open surgical biopsy costs and surgical consultation costs. The largest increase in utilization of diagnostic procedures per 100 referrals was observed for axillary ultrasound (from 3.9 in 2000 to 33.5 in 2005) and for stereotactic core biopsy (from 2.1 in 2000 to 26.8 in 2005). Per 100 referrals, the open surgical biopsy rate decreased from 34.7 (2000) to 4.6 (2005) and the number of outpatient surgical consultations fluctuated between 269.8 (2000) and 309.7 (2004). Mean costs for the diagnosis of one cancer were €1,501 and ranged from €1,223 (2002) to €1,647 (2003). Surgical biopsies comprised 54.1% of total diagnostic costs for women screened in 2000, but decreased to 9.9% for women screened in 2005. Imaging costs increased from 23.7 to 43.8%, percutaneous biopsy costs from 9.9 to 27.2%, and consultation costs from 12.3 to 19.1%. We conclude that diagnostic costs per screen-detected cancer remained fairly stable through the years, although huge changes in the use of different diagnostic procedures were observed.     

Assessing the effect of a true-positive recall case in screening mammography: does perceptual priming alter radiologists' performance?

Objective:

To measure the effect of the insertion of less-difficult malignant cases on subsequent breast cancer detection by breast imaging radiologists.

Methods:

The research comprises two studies. Study 1: 8 radiologists read 2 sets of images each consisting of 40 mammographic cases. Set A contained four abnormal cases, and Set B contained six abnormal cases, including two priming cases (less difficult malignancies) placed at intervals of three and five subsequent cases before a subtle cancer. Study 2: 16 radiologists read a third condition of the same cases, known as Set C, containing six abnormal cases and two priming cases immediately preceding the subtle cancer cases. The readers were asked to localize malignancies and give confidence ratings on decisions.

Results:

Although not significant, a decrease in performance was observed in Set B compared with in Set A. There was a significant increase in the receiver operating characteristic (ROC) area under the curve (z = −2.532; p = 0.0114) and location sensitivity (z = −2.128; p = 0.0333) between the first and second halves of Set A and a marginal improvement in jackknife free-response ROC figure of merit (z = −1.89; p = 0.0587) between the first and second halves of Set B. In Study 2, Set C yielded no significant differences between the two halves of the study.

Conclusion:

Overall findings show no evidence that priming with lower difficulty malignant cases affects the detection of higher difficulty cancers; however, performance may decrease with priming.

Advances in knowledge:

This research suggests that inserting additional malignant cases in screening mammography sets as an audit tool may potentially lead to a decrease in performance of experienced breast radiologists.The effectiveness of screening mammography in detecting breast cancer relies heavily on accurate observer performance;¹ however, miss rates of 10–30% have been reported.^2,3 The challenge for radiologists is to gain comprehensive experience in the appearance of abnormality and keep their recall rate within acceptable limits given the low incidence of the disease.^4–6 It has been proposed that the insertion of “test malignant cases” into a “real life” clinical screening mammography set may increase cancer detection rates by artificially increasing the prevalence.⁷ However, by specifically increasing the prevalence of abnormality, there may be inadvertent effects on the detection of subsequent “real” cases.Previous work on the impact on increasing abnormality prevalence on radiologic performance has provided diverse conclusions, with one study suggesting that varying prevalence was unlikely to alter the accuracy of the radiologists,⁸ another suggesting increased diagnostic efficacy with increasing prevalence⁹ and a further arguing no significant effect.¹⁰ A study focusing on prevalence expectation, whilst showing no significant impact on reporting accuracy, did show that visual search, in terms of interpretation time and the number of visual fixations per image, was significantly changed when higher prevalence was expected.¹¹A recent study of expert breast radiologists showed that they tend to miss a much higher percentage of malignant lesions in a setting closer to the actual low-prevalence level found in the clinic than under high prevalence test conditions.⁷ However, in that study, although the false-negative rate significantly increased in the clinic setting, the false-positive rate decreased in the low-prevalence condition, although by a non-significant amount. Moreover, owing to the difficulties of performing such a study in the clinical setting, the same radiologists did not interpret the same inserted cases in both the low and high prevalence parts of the study, and as reader variability usually comprises the largest component of variance in a reader study, care should be taken when interpreting these results.Research in cognitive psychology has shown that human visual perception of the elements in our environment is greatly dependent on what was previously seen.¹² For example, detection of a target is facilitated by having seen the target (or a lookalike) before, and this effect is called “perceptual priming”. Perceptual priming as a mechanism for improving cancer detection in low-prevalence contexts such as screening mammography is an under explored area of research. In this context, priming can be understood as a mechanism that “highlights” the presence of a given target by increasing the saliency of the stimulus.¹³ It is generally accepted in the cognitive psychology literature that priming can be used to direct visual attention towards an explicit target, and that observers become proficient at finding targets when salient prompts are employed.^14,15 This has real relevance in clinical imaging, not just as an attempt to improve diagnostic efficacy but also to establish the impact of audit cases randomly inserted into a reading set to test radiologic performance. The hypothesis of the study is that the addition of malignant cases of lower difficulty (herein called “primers”) would increase the likelihood that the readers would detect subsequent malignant cases of higher difficulty presented at intervals between one and five cases after the primers.     

Does litigation influence medical practice? The influence of community radiologists' medical malpractice perceptions and experience on screening mammography

PURPOSE: To assess the relationship between radiologists' perception of and experience with medical malpractice and their patient-recall rates in actual community-based clinical settings. MATERIALS AND METHODS: All study activities were approved by the institutional review boards of the involved institutions, and patient and radiologist informed consent was obtained where necessary. This study was performed in three regions of the United States (Washington, Colorado, and New Hampshire). Radiologists who routinely interpret mammograms completed a mailed survey that included questions on demographic data, practice environment, and medical malpractice. Survey responses were linked to interpretive performance for all screening mammography examinations performed between January 1, 1996, and December 31, 2001. The odds of recall were modeled by using logistic regression analysis based on generalized estimating equations that adjust for study region. RESULTS: Of 181 eligible radiologists, 139 (76.8%) returned the survey with full consent. The analysis included 124 radiologists who had interpreted a total of 557 143 screening mammograms. Approximately half (64 of 122 [52.4%]) of the radiologists reported a prior malpractice claim, with 18 (14.8%) reporting mammography-related claims. The majority (n = 51 [81.0%]) of the 63 radiologists who responded to a question regarding the degree of stress caused by a medical malpractice claim described the experience as very or extremely stressful. More than three of every four radiologists (ie, 94 [76.4%] of 123) expressed concern about the impact medical malpractice has on mammography practice, with over half (72 [58.5%] of 123) indicating that their concern moderately to greatly increased the number of their recommendations for breast biopsies. Radiologists' estimates of their future malpractice risk were substantially higher than the actual historical risk. Almost one of every three radiologists (43 of 122 [35.3%]) had considered withdrawing from mammogram interpretation because of malpractice concerns. No significant association was found between recall rates and radiologists' experiences or perceptions of medical malpractice. CONCLUSION: U.S. radiologists are extremely concerned about medical malpractice and report that this concern affects their recall rates and biopsy recommendations. However, medical malpractice experience and concerns were not associated with recall or false-positive rates. Heightened concern of almost all radiologists may be a key reason that recall rates are higher in the United States than in other countries, but this hypothesis requires further study.     

Contrast-enhanced spectral mammography vs. mammography and MRI – clinical performance in a multi-reader evaluation

Objectives

To compare the diagnostic performance of contrast-enhanced spectral mammography (CESM) to digital mammography (MG) and magnetic resonance imaging (MRI) in a prospective two-centre, multi-reader study.

Methods

One hundred seventy-eight women (mean age 53 years) with invasive breast cancer and/or DCIS were included after ethics board approval. MG, CESM and CESM?+?MG were evaluated by three blinded radiologists based on amended ACR BI-RADS criteria. MRI was assessed by another group of three readers. Receiver-operating characteristic (ROC) curves were compared. Size measurements for the 70 lesions detected by all readers in each modality were correlated with pathology.

Results

Reading results for 604 lesions were available (273 malignant, 4 high-risk, 327 benign). The area under the ROC curve was significantly larger for CESM alone (0.84) and CESM?+?MG (0.83) compared to MG (0.76) (largest advantage in dense breasts) while it was not significantly different from MRI (0.85). Pearson correlation coefficients for size comparison were 0.61 for MG, 0.69 for CESM, 0.70 for CESM?+?MG and 0.79 for MRI.

Conclusions

This study showed that CESM, alone and in combination with MG, is as accurate as MRI but is superior to MG for lesion detection. Patients with dense breasts benefitted most from CESM with the smallest additional dose compared to MG.

Key Points

? CESM has comparable diagnostic performance (ROC-AUC) to MRI for breast cancer diagnostics.? CESM in combination with MG does not improve diagnostic performance.? CESM has lower sensitivity but higher specificity than MRI.? Sensitivity differences are more pronounced in dense and not significant in non-dense breasts.? CESM and MRI are significantly superior to MG, particularly in dense breasts.

     

Has the mammography quality standards act affected the mammography quality in North Carolina?

OBJECTIVE: The United States Food and Drug Administration implemented federal regulations governing mammography under the Mammography Quality Standards Act (MQSA) of 1992. During 1995, its first year in implementation, we examined the impact of the MQSA on the quality of mammography in North Carolina. MATERIALS AND METHODS: All mammography facilities were inspected during 1993-1994, and again in 1995. Both inspections evaluated mean glandular radiation dose, phantom image evaluation, darkroom fog, and developer temperature. Two mammography health specialists employed by the North Carolina Division of Radiation Protection performed all inspections and collected and codified data. RESULTS: The percentage of facilities that met quality standards increased from the first inspection to the second inspection. Phantom scores passing rate was 31.6% versus 78.2%; darkroom fog passing rate was 74.3% versus 88.5%; and temperature difference passing rate was 62.4% versus 86.9%. CONCLUSION: In 1995, the first year that the MQSA was in effect, there was a significant improvement in the quality of mammography in North Carolina. This improvement probably resulted from facilities' compliance with federal regulations.