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.

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.

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.

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.

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.

The incidence of fatal breast cancer measures the increased effectiveness of therapy in women participating in mammography screening

Background

Women and their health care providers need a reliable answer to this important question: If a woman chooses to participate in regular mammography screening, then how much will this choice improve her chances of avoiding a death from breast cancer compared with women who choose not to participate?

Methods

To answer this question, we used comprehensive registries for population, screening history, breast cancer incidence, and disease‐specific death data in a defined population in Dalarna County, Sweden. The annual incidence of breast cancer was calculated along with the annual incidence of breast cancers that were fatal within 10 and within 11 to 20 years of diagnosis among women aged 40 to 69 years who either did or did not participate in mammography screening during a 39‐year period (1977‐2015). For an additional comparison, corresponding data are presented from 19 years of the prescreening period (1958‐1976). All patients received stage‐specific therapy according to the latest national guidelines, irrespective of the mode of detection.

Results

The benefit for women who chose to participate in an organized breast cancer screening program was a 60% lower risk of dying from breast cancer within 10 years after diagnosis (relative risk, 0.40; 95% confidence interval, 0.34‐0.48) and a 47% lower risk of dying from breast cancer within 20 years after diagnosis (relative risk, 0.53; 95% confidence interval, 0.44‐0.63) compared with the corresponding risks for nonparticipants.

Conclusions

Although all patients with breast cancer stand to benefit from advances in breast cancer therapy, the current results demonstrate that women who have participated in mammography screening obtain a significantly greater benefit from the therapy available at the time of diagnosis than do those who have not participated.

After 20 years of follow‐up, women who participate in mammography screening have a 47% lower risk of dying from breast cancer. Although all patients with breast cancer potentially can benefit from advances in breast cancer therapy, women who participate in mammography screening obtain a significantly greater benefit from the therapy available at the time of diagnosis than those who do not participate.

One- versus Two-View Mammography Screening

In order to compare mammography screening with one versus two views, a prospective population-based study was carried out. Mammograms from 12 636 women aged 40 to 54 years were examined first as one-view screening and later as two-view screening. The initial results showed that two-view screening resulted in 349 recalls, 72 surgical biopsies, and 32 breast cancers. One-view screening resulted in 542 recalls, 61 surgical biopsies, and 29 histologically proven breast cancers. The follow-up revealed 2 additional cancers detected by one-view screening. Thus, the use of two-view screening resulted in one more cancer case being detected. The difference in breast cancer detection was not significant.

Using tumor phenotype, histological tumor distribution, and mammographic appearance to explain the survival differences between screen-detected and clinically detected breast cancers

In the era of mass screening for breast cancer with mammography, it has been noted that conventional tumor attributes and mammographic appearance are insufficient to account for the better prognosis of screen-detected tumors. Such prognostication may require additional updated pathological information regarding tumor phenotype (e.g., basal status) and histological tumor distribution (focality). We investigated this hypothesis using a Bayesian approach to analyze breast cancer data from Dalarna County, Sweden. We used data for tumors diagnosed in the Swedish Two-County Trial and early service screening period, 1977-1995, and from the mature service screening period, 1996-1998. In the early period of mammographic screening (1977-1995), the crude hazard ratio (HR) of breast cancer death for screen-detected cases compared with symptomatic ones was 0.22 (95% CI: 0.17-0.29) compared with 0.53 (95% CI: 0.34-0.76) when adjusted for conventional tumor attributes only. Using the data from the mature service screening period, 1996-1998, the HR was 0.23 (95% CI: 0.08-0.44) unadjusted and 0.71 (95% CI: 0.26-1.47) after adjustment for tumor phenotype, mammographic appearance, histological tumor distribution, and conventional tumor attributes. The area under the ROC curve (AUC) for the prediction of breast cancer deaths using these variables without the detection mode was 0.82, only slightly less than that observed when additionally including the detection mode (AUC=0.83). Using Freedman statistics, conventional tumor attributes and mammographic appearances explained 58% (95% CI: 57.5-58.6%) of the difference of breast cancer survival between the screen-detected and the clinically detected breast cancers, whereas the corresponding figure was increased to 77% (95% CI: 75.6-77.6%) when adding the two information on tumor phenotype and histological tumor distribution. The results indicated that conventional tumor attributes and mammographic appearance are not sufficient to be interim markers for explaining the survival difference between screen-detected and clinically detected cancers in the era marked by the widespread use of mammography. Additional information on tumor phenotype and histological distribution may be added as effective interim markers for explaining the benefit of the early detection of breast cancer with mammography.

A Proposal to Unify the Classification of Breast and Prostate Cancers Based on the Anatomic Site of Cancer Origin and on Long-term Patient Outcome

The similarity between the structure and function of the breast and prostate has been known for a long time, but there are serious discrepancies in the terminology describing breast and prostate cancers. The use of the large, thick-section (3D) histology technique for both organs exposes the irrationality of the breast cancer terminology. Pathologists with expertise in diagnosing prostate cancer take the anatomic site of cancer origin into account when using the terms AAP (acinar adenocarcinoma of the prostate) and DAP (ductal adenocarcinoma of the prostate) to distinguish between the prostate cancers originating primarily from the fluid-producing acinar portion of the organ (AAP) and the tumors originating either purely from the larger ducts (DAP) or from both the acini and the main ducts combined (DAP and AAP). Long-term patient outcome is closely correlated with the terminology, because patients with DAP have a significantly poorer prognosis than patients with AAP. The current breast cancer terminology could be improved by modeling it after the method of classifying prostate cancer to reflect the anatomic site of breast cancer origin and the patient outcome. The long-term survival curves of our consecutive breast cancer cases collected since 1977 clearly show that the non-palpable, screen-detected breast cancers originating from the milk-producing acini have excellent prognosis, irrespective of their histologic malignancy grade or biomarkers. Correspondingly, the breast cancer subtypes of truly ductal origin have a significantly poorer outcome, despite recent improvements in diagnosis and therapy. The mammographic appearance of breast cancers reflects the underlying tissue structure. Addition of these "mammographic tumor features" to the currently used histologic phenotypes makes it possible to distinguish the breast cancer cases of ductal origin with a poor outcome, termed DAB (ductal adenocarcinoma of the breast), from the more easily managed breast cancers of acinar origin, termed AAB (acinar adenocarcinoma of the breast), which have a significantly better outcome. This simple and easily communicable terminology could lead to better communication between the diagnostic and therapeutic team members and result in more rational treatment planning for the benefit of their patients.

Mammography casting-type calcification and risk of local recurrence in DCIS: analyses from a randomised study

BACKGROUND

We studied the association between mammographic calcifications and local recurrence in the ipsilateral breast.

METHODS

Case-cohort study within a randomised trial of radiotherapy in breast conservation for ductal cancer in situ of the breast (SweDCIS). We studied mammograms from cases with an ipsilateral breast event (IBE) and from a subcohort randomly sampled at baseline. Lesions were classified as a density without calcifications, architectural distortion, powdery, crushed stone-like or casting-type calcifications.

RESULTS

Calcifications representing necrosis were found predominantly in younger women. Women with crushed stone or casting-type microcalcifications had higher histopathological grade and more extensive disease. The relative risk (RR) of a new IBE comparing those with casting-type calcifications to those without calcifications was 2.10 (95% confidence interval (CI) 0.92-4.80). This risk was confined to in situ recurrences; the RR of an IBE associated with casting-type calcifications on the mammogram adjusted for age and disease extent was 16.4 (95% CI 2.20-140).

CONCLUSION

Mammographic appearance of ductal carcinoma in situ of the breast is prognostic for the risk of an in situ IBE and may also be an indicator of responsiveness to RT in younger women.

Multifocal breast cancer documented in large-format histology sections: long-term follow-up results by molecular phenotypes

BACKGROUND

The prognostic significance of molecular phenotype in breast cancer is well established in the literature. Recent studies have demonstrated that subgross lesion distribution (unifocal, multifocal, and diffuse) and disease extent also carry prognostic significance in this disease. However, the correlation of molecular phenotypes with subgross parameters has not yet been investigated in detail.

METHODS

In total, 444 consecutive invasive breast cancers that were documented in large-format histology slides and worked up with detailed radiologic-pathologic correlation were sampled into tissue microarray blocks and stained immunohistochemically to delineate the molecular subtypes.

RESULTS

Diffuse or multifocal distribution of the invasive component of breast carcinomas in this series was associated with a 4.14-fold respectively 2.75-fold risk of cancer-related death compared with unifocal tumors irrespective of molecular phenotype. Patients who had human epidermal growth factor receptor 2 (HER2)-positive cancers; estrogen receptor-negative, progesterone receptor-negative, and HER2-negative (triple-negative) cancers; or basal-like cancers had a 2.18-fold, 2.33-fold, and 4.07-fold risk of dying of disease, respectively, compared with patients who had luminal A carcinomas. Unifocal luminal A, HER2-positive, and basal-like cancers were associated with significantly better long-term survival outcomes than their multifocal or diffuse counterparts; luminal B and triple-negative tumors also had the same tendency. In multivariate analysis, patient age, tumor size category, lymph node status, lesion distribution, and molecular phenotypes remained significant.

CONCLUSIONS

Multifocality and diffuse distribution of the invasive component were associated with significantly poorer survival in women with breast carcinomas compared with unifocal disease in patients with luminal A, HER2 type, and basal-like cancers. Molecular classification of breast cancer is a powerful tool but gains in power when combined with conventional and subgross morphologic parameters.

Breast cancer screening: the evolving evidence

Breast cancer is a leading cause of cancer and death from cancer among women in the developed and developing world. Detecting and treating breast cancer earlier in its natural history improve prognosis and result in a reduction in breast cancer mortality. There have been eight population-based randomized controlled trials (RCTs) of mammography screening, which individually and collectively provide strong support for the efficacy of breast cancer screening. The evaluation of modern service screening also has shown that modern breast cancer screening is contributing to reductions in breast cancer mortality at a rate as good as or better than that observed in the RCTs. In the last decade, different interpretations of the evidence from the RCTs and observational studies have resulted in different screening guidelines and contentious academic debates over the balance of benefits and potential harms from breast cancer screening. In this paper, the historic and recent evidence supporting the value of breast cancer screening will be described, along with the underpinnings of the current debate over the relative and absolute benefit of regular mammography screening.

Improved differentiation between ductal and acinar prostate cancer using three-dimensional histology and biomarkers

OBJECTIVE

The aim of the study was to refine the methodology for discriminating the ductal (DAP) and acinar adenocarcinomas (AAP) of the prostate and confirm that prostate carcinoma of ductal origin is a more aggressive subtype.

MATERIAL AND METHODS

A retrospective analysis of 110 consecutive radical prostatectomy cases operated on between 2000 and 2006 and worked up using large-format "two-dimensional" (2D; 4 μm thick) and "three-dimensional" (3D; 1500 μm thick) histology sections was carried out, with an average follow-up of 5.1 years. The same material was also analysed for selected biomarkers in tissue microarray blocks. The most discriminatory biomarkers were then tested on preoperative core biopsy specimens from 24 of these patients.

RESULTS

3D histology classified 97/110 (88%) cases of AAP and 13/110 (12%) DAP, which was then confirmed in 2D specimens. The DAP cases had a significantly greater frequency of pT3a and more advanced cancers, > 20 mm tumour focus, high-grade prostatic intraepithelial neoplasia, Gleason score ≥ 7, positive margin, extracapsular extension, vascular invasion, seminal vesicle infiltration, biochemical/local recurrence, regional lymph-node metastases and distant metastases. Three biomarkers in combination (chromogranin A, epidermal growth factor receptor and p53] distinguished DAP from AAP with an accuracy of 94% (area under the curve 0.94, 95% confidence interval 0.88-0.99). The same high accuracy was achieved using these three biomarkers on the preoperative specimens.

CONCLUSIONS

Both 3D histology and the three selected biomarkers can help in accurately distinguishing DAP from AAP. The clear-cut distinction of two forms of prostate cancers by the approach advocated in this paper would allow AAP patients to undergo less radical treatment and would segregate DAP patients into a subset requiring more effective treatment regimens.

Swedish two-county trial: impact of mammographic screening on breast cancer mortality during 3 decades

PURPOSE

To estimate the long-term (29-year) effect of mammographic screening on breast cancer mortality in terms of both relative and absolute effects.

MATERIALS AND METHODS

This study was carried out under the auspices of the Swedish National Board of Health and Welfare. The board determined that, because randomization was at a community level and was to invitation to screening, informed verbal consent could be given by the participants when they attended the screening examination. A total of 133 065 women aged 40-74 years residing in two Swedish counties were randomized into a group invited to mammographic screening and a control group receiving usual care. Case status and cause of death were determined by the local trial end point committees and, independently, by an external committee. Mortality analysis was performed by using negative binomial regression.

RESULTS

There was a highly significant reduction in breast cancer mortality in women invited to screening according to both local end point committee data (relative risk [RR] = 0.69; 95% confidence interval: 0.56, 0.84; P < .0001) and consensus data (RR = 0.73; 95% confidence interval: 0.59, 0.89; P = .002). At 29 years of follow-up, the number of women needed to undergo screening for 7 years to prevent one breast cancer death was 414 according to local data and 519 according to consensus data. Most prevented breast cancer deaths would have occurred (in the absence of screening) after the first 10 years of follow-up.

CONCLUSION

Invitation to mammographic screening results in a highly significant decrease in breast cancer-specific mortality. Evaluation of the full impact of screening, in particular estimates of absolute benefit and number needed to screen, requires follow-up times exceeding 20 years because the observed number of breast cancer deaths prevented increases with increasing time of follow-up.

A new era in the diagnosis and treatment of breast cancer

Randomized controlled mammography screening trials and the evaluation of service screening have unequivocally proven that regular mammography screening significantly reduces mortality from breast cancer. This evidence contradicts the theory of Fisher, claiming that breast cancer is a systemic disease from its inception and undermines the justification for systemic therapy in most screen-detected cancers, because they are still localized to the breast and can be cured by local treatment alone. When high quality mammographic screening is offered at regular intervals to 40- to 74- year-old women, over 50% of the invasive cancers will be detected in the size range of 1-14 mm, fewer than 20% will be axillary node positive, and only about 20% will be poorly differentiated. This predominance of early-stage disease has created a revolutionary new era for those involved in the diagnosis and treatment of patients with breast cancer.

The role of radiological-pathological correlation in diagnosing early breast cancer: the pathologist's perspective

Early breast carcinoma, defined as purely in situ cancer and invasive carcinomas < 15 mm, represents the most frequent category of breast carcinomas in diagnostic routine in a regularly screened population. These tumors are usually detected with mammography screening and are preoperatively characterized with radiological imaging. The role of pathology in preoperative settings is to help understand the subgross morphology and to confirm malignancy in biopsy material. Postoperatively, the pathologist needs to verify the size of the cancer (defined as the largest dimension of the largest invasive focus), the extent of the disease (defined as the area or the volume of the breast tissue containing all the malignant foci), the distribution of the in situ and invasive lesions (as unifocal, multifocal, or diffuse), and intratumoral and intertumoral heterogeneity (in addition to determining margin status, histologic tumor type, hormone receptor status, and other parameters). Despite their small size, early breast carcinomas often exhibit complex morphology as they are multifocal/diffuse in about 60% and extensive (occupying an area ≥ 4 cm) in 40% of the cases. Routine use of large-format histopathology technique is a prerequisite for detailed correlation of the radiologic and histopathologic findings and for the correct assessment of these parameters. Breast pathologists must be aware of the advantages and disadvantages of the different imaging modalities and have detailed information about the radiological findings before work-up of the operative specimen. Multidisciplinary preoperative and postoperative tumor board meetings are essential in guiding the pathologists and in confirming the radiological findings. Interdisciplinary diagnosis is inevitably becoming the new gold standard in the diagnosis and management of early breast carcinomas.

Effectiveness of population-based service screening with mammography for women ages 40 to 49 years: evaluation of the Swedish Mammography Screening in Young Women (SCRY) cohort

BACKGROUND

The effectiveness of mammography screening for women ages 40 to 49 years still is questioned, and few studies of the effectiveness of service screening for this age group have been conducted.

METHODS

Breast cancer mortality was compared between women who were invited to service screening at ages 40 to 49 years (study group) and women in the same age group who were not invited during 1986 to 2005 (control group). Together, these women comprise the Mammography Screening of Young Women (SCRY) cohort, which includes all Swedish counties. A prescreening period was defined to facilitate a comparison of mortality in the absence of screening. The outcome measure was refined mortality, ie, breast cancer death for women who were diagnosed during follow-up at ages 40 to 49 years. Relative risks (RRs) with 95% confidence intervals (CIs) were estimated.

RESULTS

There was no significant difference in breast cancer mortality during the prescreening period. During the study period, there were 803 breast cancer deaths in the study group (7.3 million person-years) and 1238 breast cancer deaths in the control group (8.8 million person-years). The average follow-up was 16 years. The estimated RR for women who were invited to screening was 0.74 (95% CI, 0.66-0.83), and the RR for women who attended screening was 0.71 (95% CI, 0.62-0.80).

CONCLUSIONS

In this comprehensive study, mammography screening for women ages 40 to 49 years was efficient for reducing breast cancer mortality.

Validation of a modelling approach for estimating the likely effectiveness of cancer screening using cancer data on prevalence screening and incidence

PURPOSE

This study aims to validate a biostatistical approach to predict the likely effectiveness of screening in reducing advanced disease in the absence of data on incident screen and interval cancers.

METHODS

We derived the predicted relative reduction in advanced stage disease following screening from the expected proportion of advanced disease following screening and the observed proportion of advanced disease detected clinically among the controls. We compared the predicted estimates to those observed in a randomised trial.

RESULTS

Using our method, the predicted estimates of relative reduction in node positive breast cancer following screening were comparable to the observed estimates for the age groups 50-59 and 60-69 in the screening study (predicted 32% vs. observed 40% (p=0.274) and predicted 34% vs. observed 45% (p=0.068), respectively). However, for the age groups 40-49 and 70-74 the predicted values were overestimates of the likely effectiveness of screening compared to the observed values (predicted 38% vs. observed 16% (p=0.014) and predicted 34% vs. observed 0% (p=0.001), respectively).

CONCLUSION

When the number of cancer cases is more than hundred, the method of prediction using only prevalence screen data may be accurate. Where cancers are less common, for example in small populations or young age groups, further data from interval cancers or incidence screens may be necessary.

Differences in Endpoints between the Swedish W-E (Two County) Trial of Mammographic Screening and the Swedish Overview: Methodological Consequences

Objectives

To characterize and quantify the differences in the number of cases and breast cancer deaths in the Swedish W-E Trial compared with the Swedish Overview Committee (OVC) summaries and to study methodological issues related to trials in secondary prevention.

Setting

The study population of the W-E Trial of mammography screening was included in the first (W and E county) and the second (E-county) OVC summary of all Swedish randomized mammography screening trials. The OVC and the W-E Trial used different criteria for case definition and causes of death determination.

Method

A Review Committee compared the original data files from Wand E county and the first and second OVC. The reason for a discrepancy was determined individually for all non-concordant cases or breast cancer deaths.

Results

Of the 2615 cases included by the W-E Trial or the OVC, there were 478 (18%) disagreements. Of the disagreements 82% were due to inclusion/exclusion criteria, and 18% to disagreement with respect to cause of death or vital status at ascertainment. For E-County, the OVC inclusion rules and register based determination of cause of death (second OVC) rather than individual case review (W-E Trial and 1st OVC) resulted in a reduction of the estimate of the effect of screening, but for W-County the difference between the original trial and the OVC was modest.

Conclusions

The conclusion that invitation to mammography screening reduces breast cancer mortality remains robust. Disagreements were mainly due to study design issues, while disagreements about cause of death were a minority. When secondary research does not adhere to the protocols of the primary research projects, the consequences of such design differences should be investigated and reported. Register linkage of trials can add follow-up information. The precision of trials with modest size is enhanced by individual monitoring of case status and outcome status such as determination of cause of death.

Screening for Breast Cancer

Strong evidence supports the value of breast cancer screening with mammography, and high-quality mammography screening can be considered a major public health achievement. As noted earlier in the discussion about the evaluation of service screening, the group of women who did not participate in mammographic screening in the decades after screening had been introduced had essentially unchanged or only minor improvements in mortality compared with the pattern before the introduction of screening, despite widespread use of adjuvant chemotherapy or hormonal therapy. Breast cancer should be treated in its preclinical phase if we are to save the lives of women with this disease, and a considerable body of evidence outlines best practices that, with broader adherence, would result in greater breast cancer mortality reductions than have been observed to date.

Mammography and breast cancer: the new era

OBJECTIVES

To review the evidence demonstrating that early detection of breast cancer substantially decreases death from the disease, and to demonstrate that the significant change in the outcome of breast cancer patients results from a combination of early detection and surgical removal of breast cancer, as treatment of the late stage disease provides little impact on ultimate outcome.

METHOD

Review results of the randomized controlled trials of mammographic screening and the published results of service screening.

RESULTS

Both randomized controlled trials and service screening, when performed properly, provide unequivocal evidence demonstrating that arresting the disease in its preclinically detectable phase has significant impact on outcome. Primary emphasis should be upon preventing breast cancer from developing to metastatic disease.

CONCLUSIONS

Numerous scientific trials have repeatedly and convincingly confirmed that breast cancer is progressive rather than a systemic disease from its inception. Progression of breast cancer can be arrested through detection and treatment at an early phase. The time at which disease progression is arrested has significant impact on clinical outcome, making mammographic screening a key factor in the control of breast cancer.

Quantifying the potential problem of overdiagnosis of ductal carcinoma in situ in breast cancer screening

The relevance of detection of ductal carcinoma in situ (DCIS) in a breast cancer screening programme, and the extent of overdiagnosis of non-progressive lesions, remains controversial. It was the purpose of this paper to estimate the incidence of non-progressive, 'overdiagnosed' DCIS. We defined non-progressive DCIS (DCIS(0)) as DCIS which could not have progressed to invasive disease if left untreated. Progressive DCIS (DCIS(1)) was defined as DCIS which has the propensity to progress to invasive disease. We fitted a Markov process model of the incidence of progressive and non-progressive DCIS, the transition of the former to preclinical invasive disease and the subsequent progression to clinical symptomatic cancer. We used data from the Swedish Two-County Trial and from service screening programmes in the UK, Netherlands, Australia and the USA to estimate the incidence of progressive and non-progressive DCIS, and the detection rates of each at the first and subsequent screening. Average incidence of non-progressive DCIS was 1.11 per 100000 per year. Average incidence of progressive DCIS was 2.1 per 1000 per year. At prevalence screen, 37% of DCIS cases were estimated to be non-progressive. A woman attending prevalence screen has a 19 times greater chance of having a progressive DCIS or an invasive tumour diagnosed than of having a non-progressive DCIS diagnosed. At incidence screen, only 4% of DCIS cases were estimated to be non-progressive. A woman attending an incidence screen has a 166 times higher probability of having a progressive DCIS or invasive lesion diagnosed than of having a non-progressive DCIS diagnosed. There is an element of overdiagnosis of DCIS in breast cancer screening, but the phenomenon is small in both relative and absolute terms.

Oral contraceptive use and mammographic patterns

High-risk mammographic patterns represent an increased risk of contracting breast cancer and may be used as a surrogate endpoint for the disease. We examined the relationship between oral contraceptive (OC) use and mammographic patterns among 3218 Norwegian women, aged 40-56 years. Information on ever OC use, duration, and age of first OC use and other epidemiological data were obtained through questionnaires. The mammograms were categorized into five groups. Patterns I-III were combined into a low-risk group and patterns IV and V into a high-risk group. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression and adjusted for age, menopausal status, parity, age at first birth, and body mass index. Women who reported ever having used OCs were 20% more likely (OR 1.27, 95% CI 1.0-1.6) to have high-risk mammographic patterns compared with those reporting never having used OCs. There was no dose response between different measures of OC use and high-risk patterns. Among nulliparous women, ever OC users were four times more likely (OR 4.65, 95% CI 2.1-10.3) to have high-risk patterns compared with never users. Our findings suggest that, especially among nulliparous women, ever OC use may exert its effect on breast cancer risk through changes in breast tissue, which can be observed on a mammogram.

A treatment scale for axillary management in breast cancer

BACKGROUND

We have investigated a method, the Kaufman axillary treatment scale (KATS), to help assign patients with a clinically negative axilla to one of three current options of axillary management: standard axillary dissection, sentinel node sampling followed by axillary dissection if the sentinel node is positive, or no axillary surgery at all. The KATS score uses preoperative data to guide the choice of axillary treatment.

METHODS

The KATS score is calculated by adding the preoperative values of tumor size, patient age, and pathologic grade. Values range from 1 to 4 for size (1 to 9 mm, 10 to 14 mm, 15 to 19 mm, and 20 to 30 mm), 1 to 3 for age (70 years and over, 50 to 69 years, less than 50 years), and 1 to 2 for grade (low or not low) to calculate the score. The KATS score ranges from 3 to 9. We have applied this score against the SEER (Surveillance, Epidemiology, and End Results) tumor registry of 529 patients with invasive breast cancer with known pathologic data. We then validated it by applying it to our own set of 190 patients using preoperative data. The chi-square test and logistic regression analysis were used for P values (all two sided), univariate and multivariate analysis, odds ratio and confidence intervals utilizing SPSS statistics software.

RESULTS

In the SEER database using American Joint Committee on Cancer pathologic size alone, no sizable group was identified with a positive node rate neither below 8% (T1a) nor above 48% (T2). KATS scores of 3 and 4 (68 patients, group 1) identify patients with an average node positive rate of 4.4% (P <0.02, group 1 versus 2). Those patients with KATS scores of 5, 6, and 7 (341 patients, group 2) carry an average node positive rate of 22% (P <0.001, group 2 versus 3). KATS scores of 8 and 9 (120 patients, group 3) identify patients with an average node positive rate of 50% (P <0.001, group 3 versus 1). Similar results were found on our own group of 190 patients using preoperative available data. KATS scores of 3 or 4 (11 patients, group 1) had no positive nodes. Group 2 (100 patients, KATS score 5, 6, and 7) had an average 30% node positive rate. Group 3 (79 patients, KATS score 8 and 9) had 61% node positive rate. The KATS score allows the clinician to separate patients into three axillary management groups. Group 1 are those patients who may need no axillary surgery at all. Group 2 are patients who would benefit from sentinel node mapping. Group 3 has a node positive rate (61%) similar to that of clinically palpable nodes (since not all clinically palpable nodes are positive). Group 3 patients may be considered for standard axillary dissection, similar to the palpable node patient. If group 3 patients have sentinel node mapping, more than half of these patients require axillary dissection and the impact of false negative sentinel node procedures may become clinically significant.

CONCLUSIONS

An axillary treatment score has been developed to aid in the triage of patients toward reasonable axillary treatment choices for the benefit of the patient. The KATS score is a guideline and not a mandate. The KATS score attempts to use breakpoints that are both clinically practical and validated by scientific data. Like many other attempts to categorize patients, there is a continuum of data points along any variable. The treating physician utilizing the full array of available data on each patient makes the final clinical decision of axillary management.

Beyond randomized controlled trials: organized mammographic screening substantially reduces breast carcinoma mortality

BACKGROUND

The efficacy of mammographic screening in the reduction of breast carcinoma mortality has been demonstrated in randomized controlled trials. However, the evaluation of organized screening outside of research settings (so-called "service screening") faces unique methodologic and conceptual challenges. The current study describes the evaluation of organized mammography screening in a clinical setting and demonstrates the benefit obtained from service screening in two Swedish counties.

METHODS

In the group of subjects ages 20--69 years, there were 6807 women diagnosed with breast carcinoma over a 29-year period in 2 counties in Sweden and 1863 breast carcinoma deaths. All patients were classified from patient charts based on their screening status (i.e., whether they had been invited to undergo screening and whether they actually had undergone screening). The number of women who lived in the 2 counties during the 29-year study period was provided by the Central Bureau of Statistics. Breast carcinoma-specific mortality was compared across three time periods: 1) 1968--1977, when no screening was taking place because mammography had not been introduced; 2) 1978--1987, the approximate period of the Two-County randomized controlled trial of screening in women ages 40--74 years; and 3) 1988--1996, when all women in the 2 counties ages 40--69 years were invited to undergo screening (service screening). When comparing breast carcinoma mortality in screened women with that in women diagnosed before screening was introduced, a correction for self-selection bias was incorporated to prevent overestimation of the benefit of screening.

RESULTS

The mortality from incident breast carcinoma diagnosed in women ages 40-69 years who actually were screened during the service screening period (1988--1996) declined significantly by 63% (relative risk [RR] = 0.37; 95% CI, 0.30--0.46) compared with breast carcinoma mortality during the time period when no screening was available (1968--1977). The mortality decline was 50% (RR = 0.50; 95% CI, 0.41--0.60) when breast carcinoma mortality among all women who were invited to undergo screening (nonattendees included) was compared with breast cancer mortality during the time period when no screening was available (1968--1977). The reduction in mortality observed during the service screening period, adjusted for selection bias, was 48% (RR = 0.52; 95% CI, 0.43--0.63). No significant change in breast carcinoma mortality was observed over the three time periods in women who did not undergo screening. This group included women ages 20--39 years because these individuals were never invited to undergo screening, and women ages 40--69 years who did not undergo screening (not invited during the randomized trial or invited during the second and third time periods but declined).

CONCLUSIONS

Regular mammographic screening resulted in a 63% reduction in breast carcinoma death among women who actually underwent screening. The policy of invitation to organized screening with mammography appears to have reduced breast carcinoma mortality by 50% in these 2 counties.

The pressing need for better histologic-mammographic correlation of the many variations in normal breast anatomy

Mammography screening calls for a reevaluation of the working relationship between physicians dealing with the diagnosis and treatment of breast diseases. In this new era, histologic-mammographic correlation needs to be extended to correctly describe the deceptive mammographic findings that correspond to variations in normal breast tissue. Progress in histologic-mammographic correlation can only be made by overcoming the limitations inherent to the traditional histologic technique by examining a histologic specimen of greater length, width, and depth. There are several distinct advantages to using the large-section histology technique in the diagnosis of breast diseases. The subgross (three-dimensional) histology technique serves to bridge the gap that separates the pathologist and radiologist, bringing them to a common ground for a better understanding of breast morphology. These improvements in communication between the members of the diagnostic team will serve to optimize the sensitivity and specificity of breast cancer diagnosis.

The Swedish Two-County Trial twenty years later. Updated mortality results and new insights from long-term follow-up

The benefit of invitation to mammographic screening observed in this trial is maintained as a highly significant 32% reduction in breast cancer mortality. Mammographic screening for breast cancer continues to save lives after up to 20 years. Screening derives this benefit by improving the distribution of tumors diagnosed with respect to prognostic categories based on node status, size, and histology of tumors. There is potential for modern screening programs with shorter interscreening intervals to achieve even greater improvements in prognostic category and greater reductions in breast cancer mortality. Mammography can discriminate a subpopulation of high-risk cases, those displaying casting-type calcifications on the mammogram, among very small tumors, with fundamental implications for diagnosis and treatment.