Imaging Changes and Outcomes of Patients Undergoing Active Monitoring for Ductal Carcinoma In Situ: Seven-Year Follow-up Study

RATIONALE AND OBJECTIVES

To determine the imaging changes and their associated positive predictive value (PPV) for invasive breast cancer in women undergoing active monitoring for ductal carcinoma in situ (DCIS).

MATERIALS AND METHODS

In this seven-year follow-up retrospective IRB-exempted cohort study, we reviewed patients diagnosed with DCIS who elected active monitoring between 2003 and 2022 at a single academic institution. Imaging characteristics, histopathology at initial diagnosis, and subsequent follow-up were recorded. Low-risk DCIS was defined as low or intermediate grade and hormone receptor (HR) positive (estrogen and/or progesterone receptor positive) disease diagnosed in women at least 40 years of age. Progression was defined as subsequent ipsilateral invasive breast cancer diagnosis.

RESULTS

There were 39 patients with a median age of 58.4 years (IQR: 51.1-69.6 years) and a median follow-up of 4.3 years (range: 0.6-16.4 years). Nearly two thirds of patients (64%, 25/39) had stable imaging (range: 0.6-16.4 years) and remained progression-free during active monitoring. Among the remaining 14 patients (36%), there were 24 imaging findings which prompted 22 subsequent core needle biopsies (range: 1-3 biopsies per patient) and two surgical biopsies. The PPV of invasive cancer was 29% (7/24) overall and 38% (3/8) for masses, 33% (3/9) for calcifications, 17% (1/6) for non-mass enhancement, and 0% (0/1) for architectural distortion.

CONCLUSION

Of the radiographic changes prompting an additional biopsy, development of a new mass (38%) and new calcifications (33%) had the highest PPV for invasive progression. Close imaging follow-up should be a critical component for patients undergoing monitoring for DCIS.

Overdiagnosis Due to Screening Mammography for Breast Cancer among Women Aged 40 Years and Over: A Systematic Review and Meta-Analysis

The current systematic review and meta-analysis was conducted to estimate the incidence of overdiagnosis due to screening mammography for breast cancer among women aged 40 years and older. A PRISMA systematic search appraisal and meta-analysis were conducted. A systematic literature search of English publications in PubMed, Web of Science, EMBASE, Scopus, and Google Scholar was conducted without regard to the region or time period. Generic, methodological, and statistical data were extracted from the eligible studies. A meta-analysis was completed by utilizing comprehensive meta-analysis software. The effect size estimates were calculated using the fail-safe N test. The funnel plot and the Begg and Mazumdar rank correlation tests were employed to find any potential bias among the included articles. The strength of the association between two variables was assessed using Kendall’s tau. Heterogeneity was measured using the I-squared (I2) test. The literature search in the five databases yielded a total of 4214 studies. Of those, 30 articles were included in the final analysis, with sample sizes ranging from 451 to 1,429,890 women. The vast majority of the articles were retrospective cohort designs (24 articles). The age of the recruited women ranged between 40 and 89 years old. The incidence of overdiagnosis due to screening mammography for breast cancer among women aged 40 years and older was 12.6%. There was high heterogeneity among the study articles (I2 = 99.993), and the pooled event rate was 0.126 (95% CI: 15 0.101–0.156). Despite the random-effects meta-analysis showing a high degree of heterogeneity among the articles, the screening tests have to allow for a certain degree of overdiagnosis (12.6%) due to screening mammography for breast cancer among women aged 40 years and older. Furthermore, efforts should be directed toward controlling and minimizing the harmful consequences associated with breast cancer screening.

Mixed-Methods Study to Predict Upstaging of DCIS to Invasive Disease on Mammography

BACKGROUND. The incidence of ductal carcinoma in situ (DCIS) has steadily increased, as have concerns regarding overtreatment. Active surveillance is a novel treatment strategy that avoids surgical excision, but identifying patients with occult invasive disease who should be excluded from active surveillance is challenging. Radiologists are not typically expected to predict the upstaging of DCIS to invasive disease, though they might be trained to perform this task. OBJECTIVE. The purpose of this study was to determine whether a mixed-methods two-stage observer study can improve radiologists' ability to predict upstaging of DCIS to invasive disease on mammography. METHODS. All cases of DCIS calcifications that underwent stereotactic biopsy between 2010 and 2015 were identified. Two cohorts were randomly generated, each containing 150 cases (120 pure DCIS cases and 30 DCIS cases upstaged to invasive disease at surgery). Nine breast radiologists reviewed the mammograms in the first cohort in a blinded fashion and scored the probability of upstaging to invasive disease. The radiologists then reviewed the cases and results collectively in a focus group to develop consensus criteria that could improve their ability to predict upstaging. The radiologists reviewed the mammograms from the second cohort in a blinded fashion and again scored the probability of upstaging. Statistical analysis compared the performances between rounds 1 and 2. RESULTS. The mean AUC for reader performance in predicting upstaging in round 1 was 0.623 (range, 0.514-0.684). In the focus group, radiologists agreed that upstaging was better predicted when an associated mass, asymmetry, or architectural distortion was present; when densely packed calcifications extended over a larger area; and when the most suspicious features were focused on rather than the most common features. Additionally, radiologists agreed that BI-RADS descriptors do not adequately characterize risk of invasion, and that microinvasive disease and smaller areas of DCIS will have poor prediction estimates. Reader performance significantly improved in round 2 (mean AUC, 0.765; range, 0.617-0.852; p = .045). CONCLUSION. A mixed-methods two-stage observer study identified factors that helped radiologists significantly improve their ability to predict upstaging of DCIS to invasive disease. CLINICAL IMPACT. Breast radiologists can be trained to better predict upstaging of DCIS to invasive disease, which may facilitate discussions with patients and referring providers.

The seven key challenges for life-critical shared decision making systems

BACKGROUND

Shared decision making (SDM) for life-critical diseases or conditions is a crucial type of SDM. This type of SDM is still greatly underdeveloped and it faces a number of key challenges. The main goal of this study is to identify the challenges that impede the development and use of life-critical SDM.

METHODS

This is a hybrid research and systematic / narrative review paper. Its results were derived by analyzing reviews already conducted by the authors when they were working on six recently published papers. These papers had collectively required two systematic reviews and four narrative reviews. The topics covered in the six published papers were related to computer-aided diagnosis (CAD) in medicine, the analysis of health state utilities, and the selection of the best treatment for life-critical diseases / conditions. A new narrative review was also executed to explore some new issues.

RESULTS

The key challenges for life-critical SDM relate to the following aspects: The mathematical models used to make the decisions, the data used to feed these models, the role the patient plays within the SDM framework, and finally, the role healthcare professionals play along with the pertinent rules and regulations that guide the use of this type of SDM today.

CONCLUSIONS

Life-critical SDM is the most important type of SDM. However, some challenges impede its successful development and use. A number of developments and enhancements need to be made urgently for this type of SDM to become widely acceptable and useful. The seven key challenges identified in this study and the suggested directions for future research offer a compelling path towards elevating life-critical SDM to the next level and do so both effectively and efficiently.

Overdiagnosis and Risks of Breast Cancer Screening

Since its widespread introduction 30 years ago, screening mammography has contributed to substantial reduction in breast cancer-associated mortality, ranging from 15% to 50% in observational trials. It is currently the best examination available for the early diagnosis of breast cancer, when survival and treatment options are most favorable. However, like all medical tests and procedures, screening mammography has associated risks, including overdiagnosis and overtreatment, false-positive examinations, false-positive biopsies, and radiation exposure. Women should be aware of the benefits and risks of screening mammography in order to make the most appropriate care decisions for themselves.

Preventive Care: How Mammography Utilization Changes as Women Age

OBJECTIVE

To evaluate the impact of comorbid conditions and age on mammography use.

METHODS

We used data from the 2011 to 2015 Medical Expenditure Panel Survey, which contained records for 40,752 women over the age of 40. Use was defined as a mammogram within the previous 1 or 2 years, analyzed separately. A logit model was employed to evaluate associations between use and comorbidities and age. Statistical significance was defined by a P < .05 by two-sided test.

RESULTS

Of the 36,575 women in our study sample, 45.9%, 43.6%, 3.9%, and 5.7% reported a history of hypertension (HTN), hyperlipidemia (HLD), prior heart attack (MI), and prior stroke, respectively. Among women without a comorbid condition, there was 47.3% annual mammography use. HTN and HLD were associated with increased use (2.5 and 6.8 percentage points [pp], P< .01). In comparison, prior MI was associated with decreased annual use (-8.2 pp, P < .01). Prior stroke was not significantly associated with annual mammography (-1.5 pp, P = .42). Results were similar for biennial use. The age trend in use showed that the age with maximum screening use was approximately 60 years.

DISCUSSION

Mammography use was higher in patients with HTN and HLD and lower in patients with prior MI and stroke, which may reflect differences in comorbidity-related general health care use. Use increased until it peaked around age 60. An understanding of how mammography use naturally evolves as people age may help better target specific populations and improve overall use of preventive care.

Outcomes of Ductal Carcinoma In Situ According to Detection Modality: A Multicenter Study Comparing Recurrence Between Mammography and Breast US

The purpose of this study was to determine whether disease recurrence and intrinsic characteristics of ductal carcinoma in situ (DCIS) are associated with the imaging method of detection in asymptomatic women. This multicenter, retrospective study included 844 women treated for asymptomatic DCIS who had pre-operative mammography and breast ultrasonography (US) studies available. Of the 844 women, 25 (3.0%) developed recurrences. Patients in the US group had significantly lower 5- and 10-y recurrence-free survival (RFS) rates compared with patients in the mammography group (p = 0.011). US-detected DCIS showed significantly lower 5-and 10-y RFS rates compared with mammography-detected DCIS in patients <50 y or with mammographically dense breasts (p = 0.002 and 0.002, respectively). US as the detection modality (hazard ratio [HR]: 4.451; 95% confidence interval [CI]: 1.530, 12.950; p = 0.006) and HER2 positivity (HR: 4.036; 95% CI: 1.438; 11.330; p = 0.008) were significantly associated with recurrence. We concluded that US as the detection modality and HER2 positivity were significantly associated with recurrence in patients treated for asymptomatic DCIS.

Monitoring Progression of Ductal Carcinoma In Situ Using Photoacoustics and Contrast-Enhanced Ultrasound

Breast cancer is the leading form of cancer in women, accounting for approximately 41,400 deaths in 2018. While a variety of risk factors have been identified, physical exercise has been linked to reducing both the risk and aggressiveness of breast cancer. Within breast cancer, ductal carcinoma in situ (DCIS) is a common finding. However, less than 25% of DCIS tumors actually progress into invasive breast cancer, resulting in overtreatment. This overtreatment is due to a lack of predictive precursors to assess aggressiveness and development of DCIS. We hypothesize that tissue oxygenation and perfusion measured by photoacoustic and contrast-enhanced ultrasound imaging, respectively, can predict DCIS aggressiveness. To test this, 20 FVB/NJ and 20 SV40Tag mice that genetically develop DCIS-like breast cancers were divided evenly into exercise and control groups and imaged over the course of 6 weeks. Tissue oxygenation was a predictive precursor to invasive breast cancer for FVB/NJ mice (P = 0.015) in the early stages of tumor development. Meanwhile, perfusion results were inconclusive (P > 0.2) as a marker for disease progression. Moreover, voluntary physical exercise resulted in lower weekly tumor growth and significantly improved median survival (P = 0.014).

Screening for breast cancer in 2018-what should we be doing today?

Although screening mammography has delivered many benefits since its introduction in Canada in 1988, questions about perceived harms warrant an up-to-date review. To help oncologists and physicians provide optimal patient recommendations, the literature was reviewed to find the latest guidelines for screening mammography, including benefits and perceived harms of overdiagnosis, false positives, false negatives, and technologic advances. For women 40-74 years of age who actually participate in screening every 1-2 years, breast cancer mortality is reduced by 40%. With appropriate corrections, overdiagnosis accounts for 10% or fewer breast cancers. False positives occur in about 10% of screened women, 80% of which are resolved with additional imaging, and 10%, with breast biopsy. An important limitation of screening is the false negatives (15%-20%). The technologic advances of digital breast tomosynthesis, breast ultrasonography, and magnetic resonance imaging counter the false negatives of screening mammography, particularly in women with dense breast tissue.

Mammography screening: A major issue in medicine

Breast cancer mortality is declining in most high-income countries. The role of mammography screening in these declines is much debated. Screening impacts cancer mortality through decreasing the incidence of number of advanced cancers with poor prognosis, while therapies and patient management impact cancer mortality through decreasing the fatality of cancers. The effectiveness of cancer screening is the ability of a screening method to curb the incidence of advanced cancers in populations. Methods for evaluating cancer screening effectiveness are based on the monitoring of age-adjusted incidence rates of advanced cancers that should decrease after the introduction of screening. Likewise, cancer-specific mortality rates should decline more rapidly in areas with screening than in areas without or with lower levels of screening but where patient management is similar. These two criteria have provided evidence that screening for colorectal and cervical cancer contributes to decreasing the mortality associated with these two cancers. In contrast, screening for neuroblastoma in children was discontinued in the early 2000s because these two criteria were not met. In addition, overdiagnosis - i.e. the detection of non-progressing occult neuroblastoma that would not have been life-threatening during the subject's lifetime - is a major undesirable consequence of screening. Accumulating epidemiological data show that in populations where mammography screening has been widespread for a long time, there has been no or only a modest decline in the incidence of advanced cancers, including that of de novo metastatic (stage IV) cancers at diagnosis. Moreover, breast cancer mortality reductions are similar in areas with early introduction and high penetration of screening and in areas with late introduction and low penetration of screening. Overdiagnosis is commonplace, representing 20% or more of all breast cancers among women invited to screening and 30-50% of screen-detected cancers. Overdiagnosis leads to overtreatment and inflicts considerable physical, psychological and economic harm on many women. Overdiagnosis has also exerted considerable disruptive effects on the interpretation of clinical outcomes expressed in percentages (instead of rates) or as overall survival (instead of mortality rates or stage-specific survival). Rates of radical mastectomies have not decreased following the introduction of screening and keep rising in some countries (e.g. the United States of America (USA)). Hence, the epidemiological picture of mammography screening closely resembles that of screening for neuroblastoma. Reappraisals of Swedish mammography trials demonstrate that the design and statistical analysis of these trials were different from those of all trials on screening for cancers other than breast cancer. We found compelling indications that these trials overestimated reductions in breast cancer mortality associated with screening, in part because of the statistical analyses themselves, in part because of improved therapies and underreporting of breast cancer as the underlying cause of death in screening groups. In this regard, Swedish trials should publish the stage-specific breast cancer mortality rates for the screening and control groups separately. Results of the Greater New York Health Insurance Plan trial are biased because of the underreporting of breast cancer cases and deaths that occurred in women who did not participate in screening. After 17 years of follow-up, the United Kingdom (UK) Age Trial showed no benefit from mammography screening starting at age 39-41. Until around 2005, most proponents of breast screening backed the monitoring of changes in advanced cancer incidence and comparative studies on breast cancer mortality for the evaluation of breast screening effectiveness. However, in an attempt to mitigate the contradictions between results of mammography trials and population data, breast-screening proponents have elected to change the criteria for the evaluation of cancer screening effectiveness, giving precedence to incidence-based mortality (IBM) and case-control studies. But practically all IBM studies on mammography screening have a strong ecological component in their design. The two IBM studies done in Norway that meet all methodological requirements do not document significant reductions in breast cancer mortality associated with mammography screening. Because of their propensity to exaggerate the health benefits of screening, case-control studies may demonstrate that mammography screening could reduce the risk of death from diseases other than breast cancer. Numerous statistical model approaches have been conducted for estimating the contributions of screening and of patient management to reductions in breast cancer mortality. Unverified assumptions are needed for running these models. For instance, many models assume that if screening had not occurred, the majority of screen-detected asymptomatic cancers would have progressed to symptomatic advanced cancers. This assumption is not grounded in evidence because a large proportion of screen-detected breast cancers represent overdiagnosis and hence non-progressing tumours. The accumulation of population data in well-screened populations diminishes the relevance of model approaches. The comparison of the performance of different screening modalities - e.g. mammography, digital mammography, ultrasonography, magnetic resonance imaging (MRI), three-dimensional tomosynthesis (TDT) - concentrates on detection rates, which is the ability of a technique to detect more cancers than other techniques. However, a greater detection rate tells little about the capacity to prevent interval and advanced cancers and could just reflect additional overdiagnosis. Studies based on the incidence of advanced cancers and on the evaluation of overdiagnosis should be conducted before marketing new breast-imaging technologies. Women at high risk of breast cancer (i.e. 30% lifetime risk and more), such as women with BRCA1/2 mutations, require a close breast surveillance. MRI is the preferred imaging method until more radical risk-reduction options are eventually adopted. For women with an intermediate risk of breast cancer (i.e. 10-29% lifetime risk), including women with extremely dense breast at mammography, there is no evidence that more frequent mammography screening or screening with other modalities actually reduces the risk of breast cancer death. A plethora of epidemiological data shows that, since 1985, progress in the management of breast cancer patients has led to marked reductions in stage-specific breast cancer mortality, even for patients with disseminated disease (i.e. stage IV cancer) at diagnosis. In contrast, the epidemiological data point to a marginal contribution of mammography screening in the decline in breast cancer mortality. Moreover, the more effective the treatments, the less favourable are the harm-benefit balance of screening mammography. New, effective methods for breast screening are needed, as well as research on risk-based screening strategies.

Imaging Features of Patients Undergoing Active Surveillance for Ductal Carcinoma in Situ

RATIONALE AND OBJECTIVES

The aim of this study was to describe the imaging appearance of patients undergoing active surveillance for ductal carcinoma in situ (DCIS).

MATERIALS AND METHODS

We retrospectively identified 29 patients undergoing active surveillance for DCIS from 2009 to 2014. Twenty-two patients (group 1) refused surgery or were not surgical candidates. Seven patients (group 2) enrolled in a trial of letrozole and deferred surgical excision for 6-12 months. Pathology and imaging results at the initial biopsy and follow-up were recorded.

RESULTS

In group 1, the median follow-up was 2.7 years (range: 0.6-13.9 years). Fifteen patients (68%) remained stable. Seven patients (32%) underwent additional biopsies with invasive ductal carcinoma diagnosed in two patients after 3.9 and 3.6 years who developed increasing calcifications and new masses. In group 2, one patient (14%) was upstaged to microinvasive ductal carcinoma at surgery. Among the patients in both groups with calcifications (n = 26), there was no progression to invasive disease among those with stable (50%, 13/26) or decreased (19%, 5/26) calcifications.

CONCLUSIONS

Among a DCIS active surveillance cohort, invasive disease progression presented as increasing calcifications and a new mass following more than 3.5 years of stable imaging. In contrast, there was no progression to invasive disease among cases of DCIS with stable or decreasing calcifications. Close imaging is a key follow-up component in active surveillance.

Margin width and local recurrence after breast conserving surgery for ductal carcinoma in situ

INTRODUCTION

Ductal Carcinoma in situ (DCIS) represents 5% of symptomatic and 20-30% of screen detected cancers. Breast conserving surgery (BCS) ± radiotherapy is performed in over 70% of women with DCIS. What constitutes an adequate margin for BCS remains unclear.

METHODS

A single institution follow up study has been conducted of 466 patients with pure DCIS treated by BCS between 2000 and 2010 of whom 292 received whole breast radiotherapy and 167 did not. Patients were selected for radiotherapy based on perceived risk of in breast tumour recurrence (IBTR). Distance to nearest radial margin was measured; 10 patients had a margin width of <1 mm, 94 had widths of 1-2 mm and 362 had widths of >2 mm. There was no association of margin width and the use of radiotherapy.

RESULTS

At a median follow up of 7.2 years there were 44 IBTR (27 DCIS and 17 invasive). There was no evidence that margin widths >2 mm resulted in a lower rate of IBTR than margin widths of 1-2 mm. The actuarial IBTR rates at 5 and 10 years for margins of 1-2 mm were 9.0% (95% CI ± 5.9%) and 9.0% (95% CI ± 5.9%) respectively and for margins of >2 mm were 8.0% (95% CI ± 3.9%) and 13.0% (95% CI ± 3.9%) respectively. Odds Ratio for IBTR 1-2 mm vs >2 mm was 0.839 (95% CI 0.392-1.827) p = 0.846. In a multivariate analysis only DCIS size predicted for IBTR (HR 2.73 p < 0.0001).

CONCLUSION

1 mm appears a sufficient margin width for BCS in DCIS irrespective of whether patients receive radiotherapy.

Are We Overtreating Ductal Carcinoma in Situ (DCIS)?

OBJECTIVE

During 2015, the media was flooded with the issue of whether ductal carcinoma in situ (DCIS) was being overtreated and whether favorable cases could be simply watched (core biopsy only followed by surveillance). To answer this question, we looked at DCIS patients treated with excision alone with margin width <1 mm as inadequate and a surrogate for no treatment (surveillance group) and margin ≥1 mm as adequate surgical excision (excision group).

METHODS

A total of 720 patients with pure DCIS treated with excision alone were stratified into two groups based on margin width and further subdivided by nuclear grade. Kaplan-Meier analysis was used to determine local recurrence-free survival. Differences in outcome were analyzed using the log-rank test.

RESULTS

The 10-year local recurrence probabilities are statistically significant for low-grade versus high-grade and surveillance alone versus excision alone. The comparison of excision alone group with margins ≥1 mm for low-grade DCIS versus high-grade DCIS shows a 10-year local recurrence-free survival rate of 13 versus 35 % (p < 0.0001). The surveillance group had (margins <1 mm) had higher rates of recurrence in both the low-grade group (51 %) and high-grade group (70 %) (p < 0.001).

CONCLUSIONS

This study indicates that there is not an acceptable level of local control in DCIS patients with tumor margins <1 mm that undergo active surveillance, regardless of tumor grade. Leaving even low-grade DCIS untreated would lead to local recurrence in more than half the patients in 10 years. Needle biopsy and surveillance for DCIS, regardless of grade, is just not adequate at this time.

Ductal carcinoma in situ of the breast: Evaluation of main presentations on magnetic resonance imaging compared with findings on mammogram and histology

SUMMARY Objective: The purpose of this study was to evaluate the various morphologies and kinetic characteristics of the ductal carcinoma in situ (DCIS) on breast magnetic resonance imaging (MRI) exam, to establish which are the most prevalent and to determine the effectiveness of the method in the detection of DCIS. Method: A prospective observational study, starting in May 2014. We evaluated 25 consecutive patients with suspicious or highly suspicious microcalcifications on mammography screening, BI-RADS categories 4 and 5, who underwent breast MRI and then surgery with proven diagnosis of pure DCIS. Surgery was considered the gold standard for correlation between histologic findings and radiological findings obtained on MRI. Results: The most frequent morphological characteristic of DCIS on MRI was non-mass-like enhancement (NMLE), p<0.001, observed in 22/25 (88%) patients (95CI 72.5-100). Of these, segmental distribution was the most prevalent, represented by 9/22 (40.91%) cases (95CI 17.4-64.4), p=0.306, and a clumped internal enhancement pattern was most commonly characterized in DCIS, observed in 13/22 (50.09%) cases. Conclusion: DCIS has a wide variety of imaging features on MRI and being able to recognize these lesions is crucial. Its most common morphological presentation is non-mass-like enhancement, while segmental distribution and a clumped internal enhancement pattern are the most common presentations. Faced with the combined analysis of these findings, percutaneous core needle biopsy (core biopsy) or vacuum-assisted biopsy (VAB) should be encouraged.

Predictive values of BI-RADS(®) magnetic resonance imaging (MRI) in the detection of breast ductal carcinoma in situ (DCIS)

PURPOSE

The purpose of this study was to evaluate BI-RADS indicators in the detection of DCIS by MRI.

MATERIALS AND METHODS

Prospective observational study that started in 2014 and lasted 24 months. A total of 110 consecutive patients were evaluated, who presented with suspicious or highly suspicious microcalcifications on screening mammography (BI-RADS categories 4 and 5) and underwent stereotactic-guided breast biopsy, having had an MRI scan performed prior to biopsy.

RESULTS

Altogether, 38 cases were characterized as positive for malignancy, of which 25 were DCIS and 13 were invasive ductal carcinoma cases. MRI had a sensitivity of 96%; specificity of 75.67%; positive predictive value (PPV) for DCIS detection of 57.14%; negative predictive value (NPV) in the detection of DCIS of 98.24%; and an accuracy of 80.80%.

CONCLUSION

BI-RADS as a tool for the detection of DCIS by MRI is a powerful instrument whose sensitivity was higher when compared to that observed for mammography in the literature. Likewise, the PPV obtained by MRI was higher than that observed in the present study for mammography, and the high NPV obtained on MRI scans can provide early evidence to discourage breast biopsy in selected cases.

Evaluation issues in the Swedish Two-County Trial of breast cancer screening: An historical review

Objectives To summarize debate and research in the Swedish Two-County Trial of mammographic screening on key issues of trial design, endpoint evaluation, and overdiagnosis, and from these to infer promising directions for the future. Methods A cluster-randomized controlled trial of the offer of breast cancer screening in Sweden, with a single screen of the control group at the end of the screening phase forms the setting for a historical review of investigations and debate on issues of design, analysis, and interpretation of results of the trial. Results There has been considerable commentary on the closure screen of the control group, ascertainment of cause of death, and cluster randomization. The issues raised were researched in detail and the main questions answered in publications between 1989 and 2003. Overdiagnosis issues still remain, but methods of estimation taking full account of lead time and of non-screening influences on incidence (taking place mainly before 2005) suggest that it is a minor phenomenon. Conclusion Despite resolution of issues relating to this trial in peer-reviewed publications dating from years, or even decades ago, issues that already have been addressed continue to be raised. We suggest that it would be more profitable to concentrate efforts on current research issues in breast cancer diagnosis, treatment, and prevention.

Diagnostic underestimation of atypical ductal hyperplasia and ductal carcinoma in situ at percutaneous core needle and vacuum-assisted biopsies of the breast in a Brazilian reference institution

Objective

To determine the rates of diagnostic underestimation at stereotactic percutaneous core needle biopsies (CNB) and vacuum-assisted biopsies (VABB) of nonpalpable breast lesions, with histopathological results of atypical ductal hyperplasia (ADH) or ductal carcinoma in situ (DCIS) subsequently submitted to surgical excision. As a secondary objective, the frequency of ADH and DCIS was determined for the cases submitted to biopsy.

Materials and Methods

Retrospective review of 40 cases with diagnosis of ADH or DCIS on the basis of biopsies performed between February 2011 and July 2013, subsequently submitted to surgery, whose histopathological reports were available in the internal information system. Biopsy results were compared with those observed at surgery and the underestimation rate was calculated by means of specific mathematical equations.

Results

The underestimation rate at CNB was 50% for ADH and 28.57% for DCIS, and at VABB it was 25% for ADH and 14.28% for DCIS. ADH represented 10.25% of all cases undergoing biopsy, whereas DCIS accounted for 23.91%.

Conclusion

The diagnostic underestimation rate at CNB is two times the rate at VABB. Certainty that the target has been achieved is not the sole determining factor for a reliable diagnosis. Removal of more than 50% of the target lesion should further reduce the risk of underestimation.

Comparison between two-dimensional synthetic mammography reconstructed from digital breast tomosynthesis and full-field digital mammography for the detection of T1 breast cancer

OBJECTIVE

To evaluate the interpretative performance of two-dimensional (2D) synthetic mammography (SM) reconstructed from digital breast tomosynthesis (DBT) in the detection of T1-stage invasive breast cancers, compared to 2D full-field digital mammography (FFDM).

METHODS

This retrospective study enrolled 214 patients. For each patient, FFDM and DBT were performed between January and June 2013, and SM was reconstructed from DBT data. Three radiologists interpreted images and recorded visibility scores and morphologies of cancers. Diagnostic performances of SM and FFDM were compared. Percentages of detected cancers and visibility scores were compared for tumour size, and presence of calcifications for each observer.

RESULTS

Observer sensitivity showed no difference for detection with SM and FFDM (P > 0.05). One observer showed a higher specificity (P = 0.02) and higher positive predictive value with SM (95 % CI 0.6-16.4), but the differences in the corresponding values between SM and FFDM for the other observers were not statistically significant. In subgroup analyses according to tumour size and presence of calcifications, percentages of detected cancers and visibility scores were not significantly different.

CONCLUSIONS

Diagnostic performances of SM and FFDM are comparable for detecting T1-stage breast cancers. Therefore, our results indicate that SM may eliminate the need for additional FFDM during DBT-based imaging.

KEY POINTS

• DBT plus FFDM increases radiation dose compared to FFDM alone. • Detecting T1-stage cancers with only SM is comparable to detection with FFDM. • Two-dimensional SM may replace dose-requiring FFDM in DBT-based imaging.

Addressing overtreatment of screen detected DCIS; the LORIS trial

Overdiagnosis, and thus overtreatment, are inevitable consequences of most screening programmes; identification of ways of minimising the impact of overdiagnosis demands new prospective research, in particular the need to separate clinically relevant lesions that require active treatment from those that can be safely left alone or monitored and only need treated if they change characteristics. Breast cancer screening has led to a large increase in ductal carcinoma in situ (DCIS) diagnoses. This is a widely heterogeneous disease and most DCIS detected through screening is of high cytonuclear grade and therefore likely to be important clinically. However, the historic practice of surgical treatment for all DCIS is unlikely to be optimal for lower risk patients. A clearer understanding of how to manage DCIS is required. This article describes the background and development of 'The low risk' DCIS trial (LORIS), a phase III trial of surgery versus active monitoring. LORIS will determine if it is appropriate to manage women with screen detected or asymptomatic, low grade and intermediate grade DCIS with low grade features, by active monitoring rather than by surgical treatment.

Will supplemental screening ultrasound increase breast cancer overdiagnosis?

Overdiagnosis refers to the detection of cancers that would never come to light in a patient's lifetime and are only identified by means of screening. Exactly how much overdiagnosis currently exists with screening mammography is uncertain. Because we do not know for certain which tumors would ultimately lead to death if left untreated and which would not, we cannot directly measure overdiagnosis and how best to estimate it is a matter of controversy. A conservative estimate of overdiagnosis with mammography would be on the order of 10%, but estimates have ranged as high as 54%. We know from multiple studies that ultrasound (US) screening mostly detects small, invasive, node-negative cancers; and in the ACRIN 6666 study, there was a greater tendency for US-only-detected tumors to be low grade than those detected with mammography. However, the population of patients undergoing screening US can be expected to differ from the average screening mammography population in that they will have higher breast density, they will be younger, and they may also have higher breast cancer risk than the population undergoing screening mammography. These factors may be associated with more aggressive tumors. There is no way to know whether we will be increasing overdiagnosis without performing a large randomized controlled study with very long-term follow-up. Even if some cancers are overdiagnosed with US, there will be a greater proportion of lethal breast cancers that are successfully treated because of screening US. The more important task is to learn how to correctly diagnose and appropriately treat nonlethal cancers.

Characteristics and behaviour of screen-detected ductal carcinoma in situ of the breast: comparison with symptomatic patients

Breast cancer is the most common malignancy in Singapore women. Ductal carcinoma in situ (DCIS) is the putative, non-obligate precursor of the majority of invasive breast cancers. The efficacy of the Singapore breast-screening pilot project in detecting early stage breast cancer led to the launch of a national breast-screening programme, BreastScreen Singapore (BSS), in January 2002. In this study, we compared clinicopathological and immunohistochemical characteristics, as well as clinical outcomes, between screen-detected and symptomatic DCIS. The study cohort comprised 1202 cases of DCIS diagnosed at Singapore General Hospital from 1994 to 2010. Comparison of clinicopathological parameters, immunohistochemical results of ER, PR, HER2, CK14, EGFR, and 34βE12, and clinical outcomes was carried out between the 2 groups. Amongst 1202 cases, 610 (50.7%) were screen-detected and 592 (49.3%) were symptomatic DCIS. Screen-detected cases were smaller in size (P < 0.001), of lower nuclear grade (P = 0.004), and more frequently expressed ER (P < 0.001). Luminal A phenotype was more frequently observed in screen-detected DCIS, while triple-negative and HER2 phenotypes were more common in symptomatic DCIS (P < 0.001). The basal-like phenotype was also more frequent in symptomatic DCIS (P = 0.041). Mean and median follow-up was 99.7 and 97.8 months, respectively, with a maximum follow-up of 246.0 months. More symptomatic patients developed invasive recurrences compared to screen-detected patients (P = 0.001). A trend for better disease-free survival was observed in screen-detected patients (P = 0.076). Patients who were screen-detected experienced better overall survival than those with symptomatic DCIS (P = 0.007). Our data indicate a more favourable outcome of screen-detected DCIS patients confirming the role of BSS in early identification of this curable disease.

Benefits and harms of mammography screening after age 74 years: model estimates of overdiagnosis

BACKGROUND

The aim of this study was to quantify the benefits and harms of mammography screening after age 74 years, focusing on the amount of overdiagnosis of invasive breast cancer and ductal carcinoma in situ (DCIS).

METHODS

Three well-established microsimulation models were used to simulate a cohort of American women born in 1960. All women received biennial screening starting at age 50 years with cessation ages varying from 74 up to 96 years. We estimated the number of life-years gained (LYG), quality-adjusted life-years, breast cancer deaths averted, false-positives, and overdiagnosed women per 1000 screens.

RESULTS

The models predicted that there were 7.8 to 11.4 LYG per 1000 screens at age 74 years (range across models), decreasing to 4.8 to 7.8 LYG per 1000 screens at age 80 years, and 1.4 to 2.4 LYG per 1000 screens at age 90 years. When adjusted for quality-of-life decrements, the LYG decreased by 5% to 13% at age 74 years and 11% to 22% at age 80 years. At age 90 to 92 years, all LYG were counterbalanced by a loss in quality-of-life, mainly because of the increasing number of overdiagnosed breast cancers per 1000 screens: 1.2 to 5.0 at age 74 years, 1.8 to 6.0 at age 80 years, and 3.7 to 7.5 at age 90 years. The age at which harms began to outweigh benefits shifted to a younger age when larger or longer utility losses because of a breast cancer diagnosis were assumed.

CONCLUSION

The balance between screening benefits and harms becomes less favorable after age 74 years. At age 90 years, harms outweigh benefits, largely as a consequence of overdiagnosis. This age was the same across the three models, despite important model differences in assumptions on DCIS.

Benefits and harms of mammography screening

Mammography screening for breast cancer is widely available in many countries. Initially praised as a universal achievement to improve women's health and to reduce the burden of breast cancer, the benefits and harms of mammography screening have been debated heatedly in the past years. This review discusses the benefits and harms of mammography screening in light of findings from randomized trials and from more recent observational studies performed in the era of modern diagnostics and treatment. The main benefit of mammography screening is reduction of breast-cancer related death. Relative reductions vary from about 15 to 25% in randomized trials to more recent estimates of 13 to 17% in meta-analyses of observational studies. Using UK population data of 2007, for 1,000 women invited to biennial mammography screening for 20 years from age 50, 2 to 3 women are prevented from dying of breast cancer. All-cause mortality is unchanged. Overdiagnosis of breast cancer is the main harm of mammography screening. Based on recent estimates from the United States, the relative amount of overdiagnosis (including ductal carcinoma in situ and invasive cancer) is 31%. This results in 15 women overdiagnosed for every 1,000 women invited to biennial mammography screening for 20 years from age 50. Women should be unpassionately informed about the benefits and harms of mammography screening using absolute effect sizes in a comprehensible fashion. In an era of limited health care resources, screening services need to be scrutinized and compared with each other with regard to effectiveness, cost-effectiveness and harms.

Complete internal audit of a mammography service in a reference institution for breast imaging

Objective

Undertaking of a complete audit of the service of mammography, as recommended by BI-RADS^®, in a private reference institution for breast cancer diagnosis in the city of São Paulo, SP, Brazil, and comparison of results with those recommended by the literature.

Materials and Methods

Retrospective, analytical and cross-sectional study including 8,000 patients submitted to mammography in the period between April 2010 and March 2011, whose results were subjected to an internal audit. The patients were followed-up until December 2012.

Results

The radiological classification of 7,249 screening mammograms, according to BI-RADS, was the following: category 0 (1.43%), 1 (7.82%), 2 (80.76%), 3 (8.35%), 4 (1.46%), 5 (0.15%) and 6 (0.03%). The breast cancer detection ratio was 4.8 cases per 1,000 mammograms. Ductal carcinoma in situ was found in 22.8% of cases. Positive predictive values for categories 3, 4 and 5 were 1.3%, 41.3% and 100%, respectively. In the present study, the sensitivity of the method was 97.1% and specificity, 97.4%.

Conclusion

The complete internal audit of a service of mammography is essential to evaluate the quality of such service, which reflects on an early breast cancer detection and reduction of mortality rates.

Cancer screening in the United States, 2015: a review of current American cancer society guidelines and current issues in cancer screening

Each year, the American Cancer Society (ACS) publishes a summary of its guidelines for early cancer detection along with a report on data and trends in cancer screening rates and select issues related to cancer screening. In this issue of the journal, we summarize current ACS cancer screening guidelines. The latest data on utilization of cancer screening from the National Health Interview Survey (NHIS) also is described, as are several issues related to screening coverage under the Affordable Care Act, including the expansion of the Medicaid program.

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.

Cuidado(!) na prevenção do câncer: ética, danos e equívocos

O artigo Principios Éticos y Prevención Cuaternaria: ¿es posible no proteger el ejercicio del principio de autonomía? é preciso em criticar a medicalização social que tem avançado na direção da prevenção. A prevenção é uma ideia apelativa, popular e medicamente defensável. O envelhecimento populacional, o sedentarismo progressivo, a epidemia de obesidade e a proliferação de doenças crônicas, bem como as limitações terapêuticas da biomedicina do século XX e XXI, reforçam essa ideia. Quase todos preferem ou apoiam o dito popular “antes prevenir que remediar”.O problema é que tal senso comum é perigoso e por vezes deve ser restrito, evitado ou mesmo combatido e reorientado, particularmente quando estão envolvidas intervenções (diagnósticas e terapêuticas) com alto potencial de dano, especialmente quando se chega ao extremo de impor procedimentos preventivos em situações em que o fundamento é precário, como na prevenção do câncer por meio da mamografia periódica no Uruguai. Além disso, as pessoas podem não querer realizar os procedimentos preventivos, pelo que não devem ser penalizadas de modo algum. Mesmo diante da mais consensual evidência, o que cabe ao profissional e ao Sistema de Saúde é aconselhar e informar; não deve haver imposição de condutas preventivas, especialmente se não houver consequências para a coletividade, como é o caso. Alguns pontos merecem destaque para compreensão da situação.Primeiro: na prevenção, as implicações éticas são - e devem ser - diferentes em relação às intervenções em pessoas adoecidas clinicamente. Na prevenção, exige-se maior rigor quanto à garantia de benefícios e evitação de danos, pois a intervenção ocorrerá em pessoas de baixo risco (assintomáticas) em que deve imperar mais fortemente o primum non nocere. Essa garantia e segurança exigem sólidos critérios científicos que somente podem ser obtidos por meio de evidências atualizadas, resultantes de meta-análises e de ensaios clínicos de alta qualidade denominados como ensaios clínicos controlados e aleatorizados. Portanto, a opinião pessoal ou coletiva de especialistas - quaisquer que sejam, médicos de família ou especialistas focais - não deve vigorar quanto aos rastreamentos. Contudo, é compreensível que mastologistas e ginecologistas tenham opiniões favoráveis ao rastreamento do câncer de mama mais cedo, porque eles entendem e tratam os “cânceres de mama clinicamente relevantes” e os “cânceres produzidos pelo rastreamento” como fenômenos idênticos, dada a impossibilidade técnica atual em diferenciar “os cânceres clinicamente relevantes” dos sobrediagnósticos resultantes do rastreamento. Tal pressão situacional e emocional, porém, não deve definir recomendações de rastreamento. Ao contrário, essa opinião deve ser informada e continuamente reformulada por evidências atualizadas de boa qualidade, que estão além da experiência pessoal e são contraintuitivas, mas hoje acessíveis facilmente.No caso da mamografia, os danos conhecidos envolvem exposição à radiação ionizante ao longo de vários anos; mastectomias desnecessárias devido ao sobrediagnóstico e sobretratamento; sofrimento psicológico quanto aos falsos positivos (com consequentes biópsias desnecessárias e complicações associadas) e falsos negativos; situações borderlines que necessitam de seguimento por vários anos, convertendo sadios em doentes; maior mortalidade devido a insuficiência cardíaca, bem como indução de câncer de pulmão.1 Nos rastreamentos, o ônus da prova fica com a “intervenção”: deve haver provas (evidências) de que os benefícios superam amplamente os danos. Em caso de dúvida, estão indicadas, pelo princípio da precaução e do primum non nocere, prudência e conduta conservadora: não intervir e discutir o balanço danos versus benefícios com a pessoa, à luz da informação disponível.Segundo: a redução da mortalidade específica é o principal, se não quase o único, critério para avaliação dos benefícios de rastreamentos de câncer. Sua estimativa em meta-análises recentes e rigorosas de ensaios clínicos envolvendo rastreamentos por mamografia reduziu-se para 15%,2 o que é pouco ou nada divulgado para o público. Além disso, nas séries históricas de mortalidade por câncer de mama nas populações, tal redução não é observada, e espera-se algum correlato nos indicadores populacionais dos resultados dos ensaios clínicos. O mais longo estudo histórico a respeito não mostra diferença significativa na mortalidade por câncer de mama entre populações rastreadas e não rastreadas.3 Nele, a redução pequena de mortalidade em ambas as populações é atribuída à melhoria da terapêutica. Esse tipo de evidência é importante. Por exemplo, ela tem sustentado a indicação do rastreamento de câncer cervicouterino há muitos anos, cuja redução histórica da mortalidade é grande e tem sido atribuída à introdução do rastreamento a partir de 1950-1960.4Terceiro: os danos do rastreamento por mamografia existem em grande proporção. Talvez os mais importantes sejam os falsos positivos e principalmente o sobrediagnóstico, situação em que o “problema” diagnosticado pelo rastreamento não teria consequências clínicas na vida da pessoa.5,6 Devido à incapacidade atual de distinção entre os “verdadeiros” casos curados precocemente, que se manifestariam clinicamente, daqueles que não se manifestariam (embora o “diagnóstico” tenha sido realizado corretamente), o sobrediagnóstico gera o sobretratamento - todos são igualmente tratados – e também o chamado “paradoxo da popularidade6”: todas as mulheres sobrediagnosticadas e sobretratadas (prejudicadas) pelo rastreamento consideram-se as (bem poucas) beneficiadas por ele, reforçando o senso comum anteriormente mencionado. Por isso, há proposta de mudança de nomenclatura para os diagnósticos produzidos por rastreamento, que mereceriam distinção dos cânceres diagnosticados clinicamente.7 A dimensão do sobrediagnóstico variou nos estudos de 10%8 até 52%9 das pessoas diagnosticadas por mamografia periódica. Recentes estudos de boa qualidade concluíram que essa proporção é de 30%.1 De cada 2.000 mulheres rastreadas ao longo de 10 anos, uma mulher terá sua vida salva pelo rastreamento; 10 serão sobrediagnosticadas e sobretratadas; e 200 mulheres receberão um resultado falso positivo, levando a estresses psicológicos e a biópsias desnecessárias.1,10Quarto: para agravar o quadro, a investigação dos danos dos rastreamentos tem se mostrado aquém do que se imagina. Os ensaios clínicos raramente se dispõem a quantificar os danos.11 Apenas 13% dos artigos sobre o rastreamento de câncer de mama citam o sobrediagnóstico como uma possibilidade, havendo ainda uma grande diferença entre periódicos científicos de medicina geral e de especialidades focais: estas últimas são mais explícitas em rejeitar dados de revisões sistemáticas e apresentam com maior frequência problemas de conflitos de interesses.12Concluindo, os critérios éticos e técnicos envolvidos e os estudos dos últimos anos questionam a recomendação do rastreamento por mamografia em qualquer idade, o que já seria motivo para revisão das recomendações ou, no mínimo, sua relativização e abertura de discussão do problema com as mulheres e a sociedade. Logo, a obrigatoriedade da realização do rastreamento por mamografia é um desserviço à saúde das mulheres do Uruguai. No Brasil, pelos mesmos pontos anteriormente abordados, merece crítica enfática a campanha “Outubro Rosa”, em que instituições privadas e filantrópicas especializadas em câncer de mama (espantosamente) recomendam o rastreamento a partir dos 40 anos13-15 e o governo brasileiro a partir dos 50 anos,16 sem abertura para compartilhamento de decisão com as mulheres devidamente informadas, nem informações claras sobre os danos. Cabe revisão, pelas autoridades sanitárias brasileiras, da indicação da mamografia a partir dos 50 anos ou dos termos dessa recomendação, abrindo discussão sobre o tema. Também merece severa - ou ainda maior crítica - a equivalente campanha preventiva “Novembro Azul”, assumida pelo governo brasileiro, que orienta explicitamente a população masculina assintomática a demandar exames preventivos de câncer de próstata, sem base de evidência para tal. Site oficial do governo federal é explícito: “Homens a partir dos 50 anos devem procurar um posto de saúde para realizar exames de rotina”,17 “A Sociedade Brasileira de Urologia recomenda que todos os homens com 45 anos de idade ou mais façam um exame de próstata anualmente, o que compreende o toque retal feito e o PSA”,17 apesar de o próprio Ministério da Saúde brasileiro não recomendar ações de rastreamento de câncer de próstata16,18 e, inclusive, haver consensual recomendação contrária derivada de avaliação recente de evidências por instituições idôneas quanto ao rastreamento com PSA (Prostate‑Specific Antigen).19 Tudo isso é um verdadeiro desafio individual e coletivo de prevenção quaternária,20,21 e esperamos que as autoridades sanitárias brasileiras e uruguaias e os médicos de família e comunidade, a exemplo do Dr. Pizzanelli, se mobilizem para corrigir esses equívocos e socializar informações e orientações bem fundamentadas a esse respeito, bem como orientar, discutir e compartilhar decisões com seus usuários.

Time trends and inter-hospital variation in treatment and axillary staging of patients with ductal carcinoma in situ of the breast in the era of screening in Southern Netherlands

BACKGROUND

To examine variation in time and place in axillary staging and treatment of patients with ductal carcinoma in situ (DCIS) of the breast.

METHODS

Trends in patients with DCIS recorded in the Eindhoven Cancer Registry diagnosed in 1991-2010 (n = 2449) were examined.

RESULTS

The use of breast conserving surgery (BCS) went from 17% to 67% in 1991-2010 and administration of radiotherapy after BCS increased to 89%. Axillary lymph node dissection decreased to almost 0%, while sentinel node biopsy was performed in 65% of patients in 2010. The proportion who underwent BCS varied between hospitals from 49% to 80%; the proportion without axillary staging ranged from 21% to 60%. Patients with screen-detected DCIS were more likely to receive BCS.

CONCLUSION

There was considerable variation in the use of BCS, radiotherapy, and axillary staging of DCIS over time and between hospitals. Patients with DCIS were more likely to be treated with BCS if their disease was detected by screening.

Mortality and recurrence patterns of breast cancer patients diagnosed under a screening programme versus comparable non-screened breast cancer patients from the same population: analytical survey from 2002 to 2012

Breast cancer screening programmes seem to bring about significant benefits, including decreased mortality, although they may also have some drawbacks such as false-negative and false-positive results. This study aims to compare the clinical outcome of a group of patients undergoing a breast cancer screening programme with that of a synchronous non-screened group of patients matched for age and follow-up period. We studied basic characteristics of epidemiology, immunohistochemistry, loco-regional relapse, distant metastases, disease-free interval and overall and specific mortality. We compared 510 patients in the screened group with 394 non-screened patients, along the period of 2002-2012. Screening was applied on a target population of 49,847 and was based on double-projection, double-read mammograms. Two years were allowed per round. Overall participation for the five rounds considered was 75.2%, with 86.5% coverage, and a total cumulative population of 123,445. The non-participant women amounted 40,794. Tumour detection rate for the screened women was 3.8 per thousand (475/123,445), while the corresponding rate for non-participants was 9.4 per thousand (382/40,797). Incidence of luminal A subtype was 15% higher in screened than that in non-screened patients (95% confidence interval (CI) 8-22%). Conversely, the triple-negative subtype was 6% higher in the non-screened group (95% CI 2-10%). Incidence of breast conservative treatments and sentinel node biopsies was significantly higher in the screened group. Overall mortality was 2.6 times higher in non-screened than that in screened group (95% CI 1.2-5.6) After 10 years of experience with our own screening programme, we believe that included patients receive a benefit versus comparable non-screened breast cancer patients, with acceptable benefit-risk relation.

Quantifying the natural history of breast cancer

Background:

Natural history models of breast cancer progression provide an opportunity to evaluate and identify optimal screening scenarios. This paper describes a detailed Markov model characterising breast cancer tumour progression.

Methods:

Breast cancer is modelled by a 13-state continuous-time Markov model. The model differentiates between indolent and aggressive ductal carcinomas in situ tumours, and aggressive tumours of different sizes. We compared such aggressive cancers, that is, which are non-indolent, to those which are non-growing and regressing. Model input parameters and structure were informed by the 1978–1984 Ostergotland county breast screening randomised controlled trial. Overlaid on the natural history model is the effect of screening on diagnosis. Parameters were estimated using Bayesian methods. Markov chain Monte Carlo integration was used to sample the resulting posterior distribution.

Results:

The breast cancer incidence rate in the Ostergotland population was 21 (95% CI: 17–25) per 10 000 woman-years. Accounting for length-biased sampling, an estimated 91% (95% CI: 85–97%) of breast cancers were aggressive. Larger tumours, 21–50 mm, had an average sojourn of 6 years (95% CI: 3–16 years), whereas aggressive ductal carcinomas in situ took around half a month (95% CI: 0–1 month) to progress to the invasive ⩽10 mm state.

Conclusion:

These tumour progression rate estimates may facilitate future work analysing cost-effectiveness and quality-adjusted life years for various screening strategies.

[Limits of mammography screening: current controversies and perspectives]

In recent years overdiagnosis has been claimed to be a major disadvantage of breast cancer screening. Studies estimating overdiagnosis have shown substantial discrepancies due to differences in the underlying epidemiological methods. Valid estimates based on studies with sufficient follow-up have shown a proportion of overdiagnosis of much less than 10 % of cancer detected by screening. Special attention should be given to intraductal carcinoma in situ as it is a precursor lesion of invasive cancer but the progression potential is poorly understood and it is currently treated similarly to invasive cancer. This highlights the urgent need for better stratification of the disease in research and clinical practice allowing individual risk-adapted appropriate therapy. In this respect new molecular and genetic biomarkers seem to be the most promising approach for predicting disease behavior.Interval carcinoma represents a limitation of breast cancer screening and the impact on screening effectiveness is still unknown. Recent studies have emphasized that interval carcinoma is more aggressive than cancer detected by screening. Hence the occurrence and distribution of interval cancer should be recorded accurately by national cancer registries and evaluated by the screening services. Quality assurance measures may help to reduce the rate of false negative cases to a minimum. Further research focusing on subgroups of screening participants with a higher risk for interval cancer occurrence seems to be a prerequisite for developing future prevention strategies.

The effect of false positive breast screening examinations on subsequent attendance: retrospective cohort study

Objectives

To investigate the effect of false positive breast screening examination results on subsequent attendance in the UK National Health Service Breast Screening Programme.

Methods

253,017 previously screened women who were invited for rescreening were studied. Attendance rates of women who had received a normal result at the last (index) screen were compared with those of women who had received a false positive result. The effects of age, type of index screening examination (prevalent or incident) and tissue sampling at assessment were investigated.

Results

Women who had a false positive prevalent index screening examination were significantly more likely to reattend than those who had a normal prevalent index screening examination (87.7% vs. 86.0%). There was no significant difference in reattendance rates between women who had a false positive incident index screening examination and those with a normal incident index screening examination. However, women who underwent needle sampling or open biopsy following false positive incident index screening examinations were 12% and 60% less likely to reattend, respectively, than women whose index screening examinations were normal ( p < 0.001), although there was variation between centres. Increasing age significantly reduced the likelihood of reattendance. The overall reattendance of women who had been screened only once was six percentage points lower than that of women who had been screened more than once.

Conclusions

The findings suggest that most women who undergo the breast screening assessment process retain confidence in breast screening. Needle sampling and open biopsy should be used judiciously in the assessment of screen-detected abnormalities in view of the reduced reattendance that results from their use after incident screening examinations.