Beneficial effect of repeated participation in breast cancer screening upon survival.

OBJECTIVES: The benefit of mammography screening in reducing population mortality from breast cancer is well established. In this paper, we estimate the effect of repeated participation at scheduled screens on case survival. METHODS: We analysed incidence and survival data on 37,079 women from nine Swedish counties who had at least one to five invitation(s) to screening prior to diagnosis, and were diagnosed with breast cancer between 1992 and 2016. Of these, 4564 subsequently died of breast cancer. We estimated the association of survival with participation in up to the most recent five screens before diagnosis. We used proportional hazards regression to estimate the effect on survival of the number of scheduled screens in which subjects participated prior to the diagnosis of breast cancer. RESULTS: There was successively better survival with an increasing number of screens in which the subject participated. For a woman with five previous screening invitations who participated in all five, the hazard ratio was 0.28 (95% confidence interval (CI) 0.25-0.33, p < 0.0001) compared to a woman attending none (86.9% vs 68.9% 20-year survival). Following a conservative adjustment for potential self-selection factors, the hazard ratio was 0.34 (95% CI 0.26-0.43, p < 0.0001), an approximate three-fold reduction in the hazard of dying from breast cancer. CONCLUSION: For those women who develop breast cancer, regular prior participation in mammography screening confers significantly better survival.

A plea for more careful scholarship in reviewing evidence: the case of mammographic screening.

Objectives: To identify issues of principle and practice giving rise to misunderstandings in reviewing evidence, to illustrate these by reference to the Nordic Cochrane Review (NCR) and its interpretation of two trials of mammographic screening, and to draw lessons for future reviewing of published results. Methods: A narrative review of the publications of the Nordic Cochrane Review of mammographic screening (NCR), the Swedish Two-County Trial (S2C) and the Canadian National Breast Screening Study 1 and 2 (CNBSS-1 and CNBSS-2). Results: The NCR concluded that the S2C was unreliable, despite the review's complaints being shown to be mistaken, by direct reference to the original primary publications of the S2C. Repeated concerns were expressed by others about potential subversion of randomisation in CNBSS-1 and CNBSS-2; however, the NCR continued to rely heavily on the results of these trials. Since 2022, however, eyewitness evidence of such subversion has been in the public domain. Conclusions: An over-reliance on nominal satisfaction of checklists of criteria in systematic reviewing can lead to erroneous conclusions. This occurred in the case of the NCR, which concluded that mammographic screening was ineffective or minimally effective. Broader and more even-handed reviews of the evidence show that screening confers a substantial reduction in breast cancer mortality. Advances in knowledge: Those carrying out systematic reviews should be aware of the dangers of over-reliance on checklists and guidelines. Readers of systematic reviews should be aware that a systematic review is just another study, with the capability that all studies have of coming to incorrect conclusions. When a review seems to overturn the current position, it is essential to revisit the publications of the primary research.

The term "classic invasive lobular carcinoma" of the breast defines breast malignancies of vastly different nature.

PURPOSE: To describe in detail the special features of a previously unappreciated "classic invasive lobular carcinoma" which is confined to the terminal ductal lobular units (TDLUs) and differs considerably from the extensive classic invasive lobular carcinoma, and to suggest specific terminology. METHOD: All invasive breast cancer cases without associated microcalcifications diagnosed in our Institution with the histopathologic diagnosis of classic invasive lobular carcinoma during the years 1996-2019 (n = 560) formed the basis of this study. The cases were prospectively classified according to their imaging biomarkers (mammographic features) and followed up to Dec 31, 2021, to determine long-term patient outcome. An additional 2600 invasive breast cancer cases (diagnosed other than invasive lobular carcinoma) without associated microcalcifications served as a reference group. Detailed histopathologic analysis used large format (10x8 cm) thin section technique and staining methods including hematoxylin-eosin (H&E), E-cadherin, cytokeratin CK 5/6, a transmembrane glycoprotein (CD44) and anti-actin or anti-smooth muscle myosin heavy chain. RESULTS: The imaging biomarkers differentiated two separate disease subgroups, having the same histopathologic diagnosis, classic invasive lobular carcinoma. One of these has the imaging biomarker of extensive architectural distortion with no central tumour mass, occupies the extralobular mesenchyme and has a long-term survival of 56%. The other subgroup forms stellate or circular non-calcified tumour masses usually smaller than 20 mm, which appear to arise in the intralobular mesenchyme, and has a significantly better long-term survival of 84%. CONCLUSIONS: There is a striking difference between the subgross histopathology and the mammographic appearance (imaging biomarkers) of two breast malignancies having the same histopathologic diagnosis, "classic invasive lobular carcinoma". The large difference in the long-term outcome of these two tumour types is even more striking. Using the same specific term, "classic invasive lobular carcinoma", to describe these two separate entities can adversely affect management decisions.

Imaging biomarkers are underutilised but highly predictive prognostic factors for the more fatal breast cancer subtypes.

PURPOSE: The development and refinement of breast imaging modalities offer a wealth of diagnostic information such as imaging biomarkers, which are primarily the mammographic appearance of the various breast cancer subtypes. These are readily available preoperatively at the time of diagnosis and can enhance the prognostic value of currently used molecular biomarkers. In this study, we investigated the relative utility of the molecular and imaging biomarkers, both jointly and independently, when predicting long-term patient outcome according to the site of tumour origin. METHODS: We evaluated the association of imaging biomarkers and conventional molecular biomarkers, (ER, PR, HER-2, Ki67), separately and combined, with long-term patient outcome in all breast cancer cases having complete data on both imaging and molecular biomarkers (n = 2236) diagnosed in our Institute during the period 2008-2019. Large format histopathology technique was used to document intra- and intertumoural heterogeneity and select the appropriate foci for evaluating molecular biomarkers. RESULTS: The breast cancer imaging biomarkers were strongly predictive of long-term patient outcome. The molecular biomarkers were predictive of outcome only for unifocal acinar adenocarcinoma of the breast (AAB), but less reliable in the multifocal AAB cases due to variability of molecular biomarkers in the individual tumour foci. In breast cancer of mesenchymal origin (BCMO), conventionally termed classic invasive lobular carcinoma, and in cancers originating from the major lactiferous ducts (ductal adenocarcinoma of the breast, DAB), the molecular biomarkers misleadingly indicated favourable prognosis, whereas the imaging biomarkers in BCMO and DAB reliably indicated the high risk of breast cancer death. Among the 2236 breast cancer cases, BCMO and DAB comprised 21% of the breast cancer cases, but accounted for 45% of the breast cancer deaths. CONCLUSIONS: Integration of imaging biomarkers into the diagnostic workup of breast cancer yields a more precise, comprehensive and prognostically accurate diagnostic report. This is particularly necessary in multifocal AAB cases having intertumoural heterogeneity, in diffuse carcinomas (DAB and BCMO), and in cases with combined DAB and AAB. In such cases, the imaging biomarkers should be prioritised over molecular biomarkers in planning treatment because the latter fail to predict the severity of the disease. In combination with the use of the large section histopathology technique, imaging biomarkers help alleviate some of the current problems in breast cancer management, such as over- and under-assessment of disease extent, which carry the risk of overtreatment and undertreatment.

Does Diffusely Infiltrating Lobular Carcinoma of the Breast Arise from Epithelial-Mesenchymal Hybrid Cells?

Classic diffusely infiltrating lobular carcinoma has imaging features divergent from the breast cancers originating from the terminal ductal lobular units and from the major lactiferous ducts. Although the term "invasive lobular carcinoma" implies a site of origin within the breast lobular epithelium, we were unable to find evidence supporting this assumption. Exceptional excess of fibrous connective tissue and the unique cell architecture combined with the aberrant features at breast imaging suggest that this breast malignancy has not originated from cells lining the breast ducts and lobules. The only remaining relevant component of the fibroglandular tissue is the mesenchyme. The cells freshly isolated and cultured from diffusely infiltrating lobular carcinoma cases contained epithelial-mesenchymal hybrid cells with both epithelial and mesenchymal properties. The radiologic and histopathologic features of the tumours and expression of the mesenchymal stem cell positive markers CD73, CD90, and CD105 all suggest development in the direction of mesenchymal transition. These hybrid cells have tumour-initiating potential and have been shown to have poor prognosis and resistance to therapy targeted for malignancies of breast epithelial origin. Our work emphasizes the need for new approaches to the diagnosis and therapy of this highly fatal breast cancer subtype.

Multifocal and diffusely infiltrating breast cancers are highly fatal subgroups needing further improvement in diagnostic and therapeutic strategies.

Physicians treating breast cancer patients often wonder why this dreaded disease is still fatal in some women despite our best diagnostic and therapeutic efforts. Our own studies on prospectively documented cases spanning several decades have given us new insights for approaching this problem. By using imaging biomarkers to classify breast cancer subtypes according to their apparent site of origin, we found that a majority of breast cancer deaths (71%) occur in a minority of breast cancers (45%). Breast cancer deaths are significantly more likely to occur in women with multifocal acinar adenocarcinoma of the breast, AAB (13.1%), diffusely invasive breast cancers of ductal origin, DAB (24 %) and breast malignancies of mesenchymal hybrid cell origin, BCMO (33.7%) compared with women having unifocal invasive breast cancers (6.1%). Preventing more of these fatal events will require a re-evaluation of the current imperfect histopathologic terminology of breast cancer with special attention to the diffuse breast cancer subtypes, intensification of multimodality imaging and multidisciplinary management, as well as application of image guided large format histopathology.

The challenging imaging and histopathologic features of diffusely infiltrating breast cancer.

PURPOSE: Clinical, imaging and outcome observations indicate that diffusely infiltrating breast cancer, presenting as a large region of architectural distortion on the mammogram and conventionally termed classic infiltrating lobular carcinoma of diffuse type, represents a very unusual breast malignancy. This article aims to draw attention to the complex clinical, imaging, and large format thin and thick section histopathologic features of this malignancy, which challenges our current diagnostic and therapeutic management practices. METHODS: Prospectively collected data from the randomized controlled trial (1977-85) and from the subsequent, ongoing population-based mammography service screening (1985-2019) with more than four decades of follow up in Dalarna County, Sweden provided the database for investigating this breast cancer subtype. Large format thick (subgross) and thin section histopathologic images of breast cancers diagnosed as "diffusely infiltrating lobular carcinoma of the breast" were correlated with their mammographic tumour features (imaging biomarkers) and the long-term patient outcome. RESULTS: This malignancy does not have a distinct tumour mass or focal skin retraction at clinical breast examination; instead, it causes an indistinct "thickening" and eventually shrinks the entire breast. A dominant feature is extensive architectural distortion on the mammograms caused by an excessive amount of cancer-associated connective tissue. Unlike other invasive breast malignancies, this subtype forms concave contours with the surrounding adipose connective tissue, a feature that makes it difficult to detect on mammograms. Women with this diffusely infiltrating breast malignancy have a 60% long-term survival. Its long-term patient outcome is surprisingly poor compared to that expected from its relatively favourable immunohistochemical biomarkers, including a low proliferation index and remains unaffected by adjuvant therapy. CONCLUSIONS: The unusual clinical, histopathologic and imaging features of this diffusely infiltrating breast cancer subtype are consistent with a site of origin quite different from that of other breast cancers. Additionally, the immunohistochemical biomarkers are deceptive and unreliable because they indicate a cancer with favourable prognostic features predictive of a good long-term outcome. The low proliferation index is usually indicative of a breast cancer with a good prognosis, but in this subtype the prognosis is poor. If we are to improve the dismal outcome of this malignancy, it will be necessary to clarify its true site of origin, which will be a prerequisite for gaining a better understanding why current management efforts often fail and why the fatality rate is so unfortunately high. Breast radiologists should be watchful for the development of subtle signs of architectural distortion at mammography. Large format histopathologic technique enables adequate correlation of the imaging and histopathologic findings.

Can we improve breast cancer management using an image-guided histopathology workup supported by larger histopathology sections?

PURPOSE: Breast radiologists examine the entire breast in full-size images, while breast pathologists examine small tissue samples at high magnification. The diagnostic information from these complementary imaging approaches can be difficult to integrate for a more clinically relevant evaluation of malignancies spanning several centimetres. We have explored the advantages and disadvantages of imaging guided larger section pathology techniques compared with the standard 2 × 2.5 cm. small section technique. METHODS: We compared the ability of conventional small section histopathology with larger section histopathology techniques to examine surgical resection margins and full disease extent. We evaluated the pre-surgical imaging workup and use of microfocus magnification radiography of sliced surgical specimens in the histopathologic evaluation of disease extent and status of surgical margins. RESULTS: Image assisted large section histopathology of excised breast tissue enables comprehensive examination of an approximately tenfold larger contiguous tissue area than is provided by conventional small section technology. Attempting to cover the full area of each consecutive slice of resected tissue is more labour-intensive and expensive with the small section approach and poses challenges in reconstituting three-dimensional tumour architecture after morcellation and sectioning. Restricting histopathologic examination to a limited number of samples provides an incomplete evaluation of surgical margins. CONCLUSIONS: A considerably improved documentation of breast cancer and a more reliable assessment of tissue margins is provided by using larger sized histopathology samples to correlate with breast imaging findings. These in turn can enable more appropriate treatment planning, improved surgical performance, fewer recurrences, and better patient outcome. Uncertainty of surgical margin evaluation inherent to the standard small section technique can lead to inappropriate decisions in surgical management and adjunctive therapy. Progress in breast diagnosis and treatment will largely depend on whether histopathology terminology and technique will undergo a revolution similar to the one that has already occurred in breast imaging.

Imaging biomarkers of breast cancers originating from the major lactiferous ducts: Ductal adenocarcinoma of the breast, DAB.

PURPOSE: As we have previously demonstrated, breast cancers originating in the major lactiferous ducts and propagating through the process of neoductgenesis are a distinct subtype of invasive breast cancers, although by current practice they are placed within the group termed ductal carcinoma in situ (DCIS) and are consequently underdiagnosed and undertreated. Imaging biomarkers provide a reliable indication of the site of origin of this breast cancer subtype (Ductal Adenocarcinoma of the breast, DAB) and have excellent concordance with long-term patient outcome. In the present paper, the imaging biomarkers of DAB are described in detail to encourage and facilitate its recognition as a distinct, invasive breast cancer subtype. METHODS: Correlation of breast imaging biomarkers with the corresponding histopathological findings using large format technology, with additional evidence from subgross, thick section histopathology to demonstrate the complex three-dimensional structure of the newly formed duct-like structures, neoducts. RESULTS: There are six imaging biomarkers (mammographic tumour features) of DAB. Four subgroups have characteristic malignant-type calcifications on the mammogram. Two of these are characterized by intraluminal necrosis producing fragmented or dotted casting type calcifications on the mammogram; another two subgroups are characterized by intraductal fluid production which may eventually calcify, producing skipping stone-like or string of pearl-like calcifications. A fifth DAB subgroup presents with bloody or serous nipple discharge and is usually occult on mammography but is detectable with galactography and magnetic resonance imaging (MRI). The sixth subgroup presents as architectural distortion on the mammogram without associated calcifications. CONCLUSIONS: Radiologists can use these well-defined imaging biomarkers to readily detect Ductal Adenocarcinoma of the Breast, DAB. Immunochemical biomarkers are generally not determined from the DAB itself, due to the erroneous assumption that DAB is non-invasive. MRI plays a crucial role in determining disease extent and guiding surgical management. The accumulating evidence that this disease subtype is, in fact, an invasive cancer, necessitates an urgent re-evaluation of the diagnostic and management criteria for this poorly understood malignancy.

Breast cancers originating from the major lactiferous ducts and the process of neoductgenesis: Ductal Adenocarcinoma of the Breast, DAB.

PURPOSE: To call attention to a highly fatal breast cancer subtype arising from the major lactiferous ducts that is currently underdiagnosed as ductal carcinoma in situ (DCIS) with or without microinvasion. METHOD: All breast cancers diagnosed at the Department of Mammography, Falun Central Hospital, Sweden, since 1977 have been classified according to their mammographic tumour features (imaging biomarkers) and followed up at regular intervals for the past four decades. The imaging biomarkers characteristic of breast cancers apparently arising from the major lactiferous ducts have been correlated with large format thin and thick section histopathology and long-term patient outcome. RESULTS: Breast cancers arising within the major lactiferous ducts propagate intraductally and produce continuously branching neoducts through epithelial-mesenchymal transformation (EMT), an invasive process termed neoductgenesis, which eventually forms a massive tumour burden. The high fatality of this breast cancer subtype indicates its truly invasive nature, although it is conventionally termed ductal carcinoma in situ, DCIS, terminology which is at odds with its poor long-term patient outcome. The neoducts are filled with multiple layers of malignant cells, have no attached lobules, and propagate by forming multiple invasive side branches. These newly formed duct-like structures are surrounded by a desmoplastic reaction (cancer associated fibroblasts, CAFs) and periductal lymphocytic infiltration. The neoducts are tightly packed together in irregular formations bearing no resemblance to the paniculate branching structure of normal lactiferous ducts. Cancers originating from the major ducts have six imaging biomarkers which can be easily recognized at breast imaging. These are described in detail in an accompanying article. CONCLUSIONS: Neoductgenesis in the breast, DAB, is similar in appearance and prognosis to ductal adenocarcinoma of the prostate, DAP. We propose the term ductal adenocarcinoma of the breast, DAB, to facilitate its recognition as a distinct invasive breast cancer subtype. The high fatality rates associated with neoductgenesis reflect the failure of current histopathologic diagnostic criteria to effectively guide therapeutic practice. When the neoducts are associated with small stellate/spiculated or spherical/oval-shaped invasive cancers arising from the terminal ductal lobular units (TDLUs), the prognosis and management are erroneously estimated according to the smaller invasive tumour(s), giving a false sense of security often resulting in undertreatment. Recognition that neoductgenesis is an invasive malignancy is a prerequisite for preventing treatment failure.

Breast cancers originating from the terminal ductal lobular units: In situ and invasive acinar adenocarcinoma of the breast, AAB.

PURPOSE: To use mammographic tumour features (imaging biomarkers) to identify and investigate breast cancers originating from the terminal ductal lobular units (TDLUs) of the breast in order to overcome the confusion arising from the current histopathology terminology, which calls cancers arising from the TDLUs either "ductal" or "lobular". METHOD: Prospectively collected data from a randomized controlled mammography screening trial with more than four decades of follow up, and data from the subsequent population-based service screening program in Dalarna County, Sweden, provided the database necessary for studying nonpalpable, primarily screen-detected breast cancer cases in their earliest detectable phases. Large format thick (subgross) and thin section histopathologic images of breast cancers originating from the TDLUs were correlated with their mammographic tumour features (imaging biomarkers) and long-term patient outcome. RESULTS: This systematic correlation indicates that imaging biomarkers can reliably determine the site of origin of breast cancers arising from the terminal ductal lobular units (TDLUs). This breast cancer subgroup has four specific mammographic tumour features: the in situ carcinomas developing from the TDLUs appear as powdery or crushed stone-like calcifications, while the invasive carcinomas appear as stellate/spiculated or circular/oval shaped tumour masses. These features are easily identified with breast imaging, either alone or in combination, unifocal or multifocal. We propose calling breast cancers of TDLU origin acinar adenocarcinoma of the breast (AAB). CONCLUSIONS: The era of early detection necessitates rectifying the current, confusing histopathological nomenclature to one that is based on the anatomical site of origin of breast cancers. Invasive cancers originating from the TDLUs are either stellate/spiculated or circular, irrespective of the complex WHO histopathologic terminology. The mortality reduction accomplished by participation in mammography screening is mostly accomplished by identifying and treating the AABs in their non-palpable, early phase. AABs detected when < 15 mm diameter with no associated carcinoma originating from the major lactiferous ducts (ductal adenocarcinoma of the breast, DAB) have a good to excellent long-term outcome, irrespective of the current terminology, which tends to lead to overtreatment of these early invasive tumours. The conventionally used prognostic factors, including immunohistochemical biomarkers, fail to identify those 1-14 mm invasive AABs tumours that are eventually fatal. This identification can be made preoperatively by including the characteristic mammographic tumour features, imaging biomarkers, in primary diagnosis, treatment planning, and predicting long-term patient outcome. Forthcoming articles will address breast malignancies originating from structures of the breast other than the TDLUs.

A new approach to breast cancer terminology based on the anatomic site of tumour origin: The importance of radiologic imaging biomarkers.

PURPOSE: To use mammographic tumour features (imaging biomarkers) to classify breast cancer according to its apparent anatomic site of origin in the new era where tumours are found at their nonpalpable, earliest detectable phase. METHOD: Large format, subgross, three-dimensional histopathologic images of breast cancer subtypes and their corresponding imaging biomarkers were correlated with large format thin section histopathology and long-term patient outcome. RESULTS: This systematic correlation indicates that breast cancers arise from three separate fibroglandular tissue components: the terminal ductal lobular units (TDLUs), the major lactiferous ducts, and in the stem cells of the mesenchyme. The resulting three cancer subgroups have distinctly different clinical, histopathological and mammographic presentations and different long-term outcomes. The relative frequency of these three breast cancer subgroups is approximately 75%, 20% and 5%, respectively. Classification of breast cancers according to their anatomic site of origin, as demonstrated with breast imaging and confirmed by subgross histopathology, correlates closely with the long-term patient outcome. CONCLUSIONS: Classification of breast cancers according to their site of origin helps overcome the inconsistencies in the current histopathologic terminology with its ductal-lobular dichotomy. The ability of the imaging biomarkers to determine the site of tumour origin and serve as a prognostic indicator emphasizes the increasingly crucial role of breast imaging in the management of breast cancer. Basing breast cancer management upon anatomically relevant terminology challenges the conventional mindset. Our proposals are based on research results from an unprecedented number of prospectively collected nonpalpable breast cancers diagnosed at their earliest detectable phases and followed up for several decades. This article is a general introduction to a series of forthcoming articles describing in detail the breast malignancies originating from the three sites of origin.

Beneficial Effect of Consecutive Screening Mammography Examinations on Mortality from Breast Cancer: A Prospective Study.

Background Previously, the risk of death from breast cancer was analyzed for women participating versus those not participating in the last screening examination before breast cancer diagnosis. Consecutive attendance patterns may further refine estimates. Purpose To estimate the effect of participation in successive mammographic screening examinations on breast cancer mortality. Materials and Methods Participation data for Swedish women eligible for screening mammography in nine counties from 1992 to 2016 were linked with data from registries and regional cancer centers for breast cancer diagnosis, cause, and date of death (Uppsala University ethics committee registration number: 2017/147). Incidence-based breast cancer mortality was calculated by whether the women had participated in the most recent screening examination prior to diagnosis only (intermittent participants), the penultimate screening examination only (lapsed participants), both examinations (serial participants), or neither examination (serial nonparticipants). Rates were analyzed with Poisson regression. We also analyzed incidence of breast cancers proving fatal within 10 years. Results Data were available for a total average population of 549 091 women (average age, 58.9 years ± 6.7 [standard deviation]). The numbers of participants in the four groups were as follows: serial participants, 392 135; intermittent participants, 41 746; lapsed participants, 30 945; and serial nonparticipants, 84 265. Serial participants had a 49% lower risk of breast cancer mortality (relative risk [RR], 0.51; 95% CI: 0.48, 0.55; P < .001) and a 50% lower risk of death from breast cancer within 10 years of diagnosis (RR, 0.50; 95% CI: 0.46, 0.55; P < .001) than serial nonparticipants. Lapsed and intermittent participants had a smaller reduction. Serial participants had significantly lower risk of both outcomes than lapsed or intermittent participants. Analyses correcting for potential biases made little difference to the results. Conclusion Women participating in the last two breast cancer screening examinations prior to breast cancer diagnosis had the largest reduction in breast cancer death. Missing either one of the last two examinations conferred a significantly higher risk. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Stephen A. Feig in this issue.

Early detection of breast cancer rectifies inequality of breast cancer outcomes.

OBJECTIVES: To explain apparent differences among mammography screening services in Sweden using individual data on participation in screening and with breast cancer-specific survival as an outcome. METHODS: We analysed breast cancer survival data from the Swedish Cancer Register on breast cancer cases from nine Swedish counties diagnosed in women eligible for screening. Data were available on 38,278 breast cancers diagnosed and 4312 breast cancer deaths. Survival to death from breast cancer was estimated using the Kaplan-Meier estimate, for all cases in each county, and separately for cases of women participating and not participating in their last invitation to screening. Formal statistical comparisons of survival were made using proportional hazards regression. RESULTS: All counties showed a reduction in the hazard of breast cancer death with participation in screening, but the reductions for individual counties varied substantially, ranging from 51% (95% confidence interval 46-55%) to 81% (95% confidence interval 74-85%). Survival rates in nonparticipating women ranged from 53% (95% confidence interval 40-65%) to 74% (95% confidence interval 72-77%), while the corresponding survival in women participating in screening varied from 80% (95% confidence interval 77-84%) to 86% (95% confidence interval 83-88%), a considerably narrower range. CONCLUSIONS: Differences among counties in the effect of screening on breast cancer outcomes were mainly due to variation in survival in women not participating in screening. Screening conferred similarly high survival rates in all counties. This indicates that the performance of screening services was similar across counties and that detection and treatment of breast cancer in early-stage reduces inequalities in breast cancer outcome.

Precision Science on Incidence and Progression of Early-Detected Small Breast Invasive Cancers by Mammographic Features.

The aim was to evaluate how the inter-screening interval affected the performance of screening by mammographic appearances. This was a Swedish retrospective screening cohort study with information on screening history and mammography features in two periods (1977-1985 and 1996-2010). The pre-clinical incidence and the mean sojourn time (MST) for small breast cancer allowing for sensitivity by mammographic appearances were estimated. The percentage of interval cancer against background incidence (I/E ratio) was used to assess the performance of mammography screening by different inter-screening intervals. The sensitivity-adjusted MSTs (in years) were heterogeneous with mammographic features, being longer for powdery and crushed stone-like calcifications (4.26, (95% CI, 3.50-5.26)) and stellate masses (3.76, (95% CI, 3.15-4.53)) but shorter for circular masses (2.65, (95% CI, 2.06-3.55)) in 1996-2010. The similar trends, albeit longer MSTs, were also noted in 1977-1985. The I/E ratios for the stellate type were 23% and 32% for biennial and triennial screening, respectively. The corresponding figures were 32% and 43% for the circular type and 21% and 29% for powdery and crushed stone-like calcifications, respectively. Mammography-featured progressions of small invasive breast cancer provides a new insight into personalized quality assurance, surveillance, treatment and therapy of early-detected breast cancer.

Mammography screening reduces rates of advanced and fatal breast cancers: Results in 549,091 women.

BACKGROUND: It is of paramount importance to evaluate the impact of participation in organized mammography service screening independently from changes in breast cancer treatment. This can be done by measuring the incidence of fatal breast cancer, which is based on the date of diagnosis and not on the date of death. METHODS: Among 549,091 women, covering approximately 30% of the Swedish screening-eligible population, the authors calculated the incidence rates of 2473 breast cancers that were fatal within 10 years after diagnosis and the incidence rates of 9737 advanced breast cancers. Data regarding each breast cancer diagnosis and the cause and date of death of each breast cancer case were gathered from national Swedish registries. Tumor characteristics were collected from regional cancer centers. Aggregated data concerning invitation and participation were provided by Sectra Medical Systems AB. Incidence rates were analyzed using Poisson regression. RESULTS: Women who participated in mammography screening had a statistically significant 41% reduction in their risk of dying of breast cancer within 10 years (relative risk, 0.59; 95% CI, 0.51-0.68 [P < .001]) and a 25% reduction in the rate of advanced breast cancers (relative risk, 0.75; 95% CI, 0.66-0.84 [P < .001]). CONCLUSIONS: Substantial reductions in the incidence rate of breast cancers that were fatal within 10 years after diagnosis and in the advanced breast cancer rate were found in this contemporaneous comparison of women participating versus those not participating in screening. These benefits appeared to be independent of recent changes in treatment regimens.

Imaging Biomarkers as Predictors for Breast Cancer Death.

BACKGROUND: To differentiate the risk of breast cancer death in a longitudinal cohort using imaging biomarkers of tumor extent and biology, specifically, the mammographic appearance, basal phenotype, histologic tumor distribution, and conventional tumor attributes. METHODS: Using a prospective cohort study design, 498 invasive breast cancer patients diagnosed between 1996 and 1998 were used as the test cohort to assess the independent effects of the imaging biomarkers and other predictors on the risk of breast cancer death. External validation was performed with a cohort of 848 patients diagnosed between 2006 and 2010. RESULTS: Mammographic tumor appearance was an independent predictor of risk of breast cancer death (P=0.0003) when conventional tumor attributes and treatment modalities were controlled. The casting type calcifications and architectural distortion were associated with 3.13-fold and 3.19-fold risks of breast cancer death, respectively. The basal phenotype independently conferred a 2.68-fold risk compared with nonbasal phenotype. The observed deaths did not differ significantly from expected deaths in the validation cohort. The application of imaging biomarkers together with other predictors classified twelve categories of risk for breast cancer death. CONCLUSION: Combining imaging biomarkers such as the mammographic appearance of the tumor with the histopathologic distribution and basal phenotype, accurately predicted long-term risk of breast cancer death. The information may be relevant for determining the need for molecular testing, planning treatment, and determining the most appropriate clinical surveillance schedule for breast cancer patients.

Impact of Overdiagnosis on Long-Term Breast Cancer Survival.

Elucidating whether and how long-term survival of breast cancer is mainly due to cure after early detection and effective treatment and therapy or overdiagnosis resulting from the widespread use of mammography provides a new insight into the role mammography plays in screening, surveillance, and treatment of breast cancer. Given information on detection modes, the impact of overdiagnosis due to mammography screening on long-term breast cancer survival was quantitatively assessed by applying a zero (cured or overdiagnosis)-inflated model design and analysis to a 15-year follow-up breast cancer cohort in Dalarna, Sweden. The probability for non-progressive breast cancer (the zero part) was 56.14% including the 44.34% complete cure after early detection and initial treatment and a small 11.80% overdiagnosis resulting from mammography screening program (8.94%) and high awareness (2.86%). The 15-year adjusted cumulative survival of breast cancer was dropped from 88.25% to 74.80% after correcting for the zero-inflated part of overdiagnosis. The present findings reveal that the majority of survivors among women diagnosed with breast cancer could be attributed to the cure resulting from mammography screening and accompanying effective treatment and therapy and only a small fraction of those were due to overdiagnosis.