Following the High-Risk Patient: Breast Cancer Risk-Based Screening.

Breast cancer (BC) is the most common cancer occurring in women in the USA today, and accounts for more than 40,000 deaths annually (Giaquinto in CA Cancer J Clin 72: 524-541, 2022). While breast cancer survival has improved over the past decades, incidence has increased, and diagnoses are being made at younger ages. This emphasizes the importance of risk evaluation, accurate prediction, and effective mitigation and risk reduction strategies. Enhanced screening can help detect cancers at an earlier stage, thus improving morbidity and mortality. This review addresses the recognition of women at high-risk for BC and monitoring strategies for those at high risk.

NCCN Guidelines® Insights: Merkel Cell Carcinoma, Version 1.2024.

The NCCN Guidelines for Merkel Cell Carcinoma (MCC) provide recommendations for diagnostic workup, clinical stage, and treatment options for patients. The panel meets annually to discuss updates to the guidelines based on comments from expert review from panel members, institutional review, as well as submissions from within NCCN and external organizations. These NCCN Guidelines Insights focus on the introduction of a new page for locally advanced disease in the setting of clinical node negative status, entitled "Clinical N0 Disease, Locally Advanced MCC." This new algorithm page addresses locally advanced disease, and the panel clarifies the meaning behind the term "nonsurgical" by further defining locally advanced disease. In addition, the guideline includes the management of in-transit disease and updates to the systemic therapy options.

Idiopathic Granulomatous Mastitis.

Idiopathic granulomatous mastitis (IGM) is a rare, benign inflammatory disorder of the breast that is often underrecognized. The exact etiology and pathophysiology are unknown, but milk stasis is felt to play a role. Classically, this condition is noninfectious, but many cases are noted to be associated with Corynebacterium species. Most patients affected are parous women with a mean age of 35, and many have breastfed within five years of diagnosis. Patients typically present with a painful mass and symptoms of inflammation, and these features can sometimes mimic breast cancer. Biopsy is needed to make a definitive diagnosis, and noncaseating granulomas are found on core biopsy. Many patients have a waxing and waning course over a period of six months to two years. Goal of treatment is to avoid surgery given poor wound healing, high risk of recurrence, and poor cosmetic outcomes. Medical treatment is preferred and includes observation, antibiotics, steroids, and immune modulators such as methotrexate. In more recent years, topical and intralesional steroids have become the treatment of choice, with similar outcomes to oral steroids.

Basal Cell Skin Cancer, Version 2.2024, NCCN Clinical Practice Guidelines in Oncology.

Basal cell carcinoma (BCC) is the most common form of skin cancer in the United States. Due to the high frequency, BCC occurrences are not typically recorded, and annual rates of incidence can only be estimated. Current estimated rates are 2 million Americans affected annually, and this continues to rise. Exposure to radiation, from either sunlight or previous medical therapy, is a key player in BCC development. BCC is not as aggressive as other skin cancers because it is less likely to metastasize. However, surgery and radiation are prevalent treatment options, therefore disfigurement and limitation of function are significant considerations. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) outline an updated risk stratification and treatment options available for BCC.

Evaluating educational interventions to increase breast density awareness among Latinas: A randomized trial in a Federally Qualified Health Center.

BACKGROUND: The objective of this randomized trial was to evaluate the short-term effect of bilingual written and interpersonal education regarding mammographic breast density (MBD). METHODS: Latinas aged 40 to 74 years who were presenting for screening mammography were recruited and randomized 1:1:1 to receive a letter with their mammogram and MBD results (usual care [UC]), a letter plus a brochure (enhanced care [ENH]), or a letter plus a brochure and telephonic promotora education (interpersonal care [INT]). Surveys were administered at enrollment (T0 ) and 2 weeks to 6 months after intervention delivery (T1 ). Differences were assessed with χ2 , Kruskal-Wallis, and McNemar tests and pairwise comparisons as appropriate. INT metrics and audio recordings were analyzed with descriptive statistics and qualitative content analysis. RESULTS: Between October 2016 and October 2019, 943 of 1108 Latina participants (85%) completed both surveys. At T1 , INT participants were more likely (P < .001) to report seeing their MBD results in the letter (70.2%) than UC (53.1%) or ENH participants (55.1%). The percentage of INT women who reported speaking with a provider about MBD (29.0%) was significantly greater (P < .001) than the percentage of UC (14.7%) or ENH participants (15.6%). All groups saw significant (P < .001) but nondifferential improvements in their knowledge of MBD as a masking and risk factor. In the INT group, the promotora delivered education to 77.1% of the 446 participants randomized to INT and answered questions at 28.3% of the encounters for an average of $4.70 per participant. CONCLUSIONS: Among Latinas in a low-resource setting, MBD knowledge may increase with written or interpersonal education, but with modest investment, interpersonal education may better improve MBD awareness and prompt patient-provider discussions.

NCCN Guidelines® Insights: Squamous Cell Skin Cancer, Version 1.2022.

The NCCN Guidelines for Squamous Cell Skin Cancer provide recommendations for diagnostic workup, clinical stage, and treatment options for patients with cutaneous squamous cell carcinoma. The NCCN panel meets annually to discuss updates to the guidelines based on comments from panel members and the Institutional Review, as well as submissions from within NCCN and external organizations. These NCCN Guidelines Insights focus on the introduction of a new surgical recommendation terminology (peripheral and deep en face margin assessment), as well as recent updates on topical prophylaxis, immunotherapy for regional and metastatic disease, and radiation therapy.

Design, implementation, and evaluation of an intervention to improve referral to smoking cessation services in breast cancer patients.

PURPOSE: Smoking is a risk factor for poor outcomes following breast reconstructive surgery. This project aimed to design and implement an intervention to consistently refer all breast cancer patients to tobacco treatment services. METHODS: In formative work, a set of processes for providers to consistently refer patients to a tobacco treatment specialist at the Nicotine Dependence Center (NDC) was designed. Elements included consistent documentation of smoking status, provider advice specific to the benefits of quitting to cancer care, referral to NDC using an "opt-out" strategy that emphasized smoking cessation as a standard part of breast cancer treatment, and reinforcement of the importance of the referral by multiple personnel. The number of referrals to the NDC and number of patients who attended their scheduled NDC appointment were measured before and 1 year after implementation. Qualitative evaluation was performed using semi-structured interviews with participating providers and patients regarding acceptability. RESULTS: The proportion of smoking patients referred to the NDC increased from 29% (22/75) before the intervention to 74% (20/27) afterward. Among those referred, attendance at the consultation increased from 41% (9/22) to 75% (15/20). This occurred despite provider interviews revealing knowledge gaps about the referral process and evidence of provider adaptation to accommodate personal practice. Feasibility and acceptability of the intervention were high. CONCLUSION: These findings suggest that similar referral interventions for all cancer patients should be pursued with the aim of embedding tobacco dependence treatment seamlessly and consistently into the cancer treatment plan of every patient who smokes cigarettes.

Evaluation of 2 breast cancer risk models in a benign breast disease cohort.

BACKGROUND: More than 1.5 million women per year have a benign breast biopsy resulting in concern about their future breast cancer (BC) risk. This study examined the performance of 2 BC risk models that integrate clinical and histologic findings in this population. METHODS: The BC risk at 5 and 10 years was estimated with the Breast Cancer Surveillance Consortium (BCSC) and Benign Breast Disease to Breast Cancer (BBD-BC) models for women diagnosed with benign breast disease (BBD) at the Mayo Clinic from 1997 to 2001. Women with BBD were eligible for the BBD-BC model, but the BCSC model also required a screening mammogram. Calibration and discrimination were assessed. RESULTS: Fifty-six cases of BC were diagnosed among the 2142 women with BBD (median age, 50 years) within 5 years (118 were diagnosed within 10 years). The BBD-BC model had slightly better calibration at 5 years (0.89; 95% confidence interval [CI], 0.71-1.21) versus 10 years (0.81; 95% CI, 0.70-1.00) but similar discrimination in the 2 time periods: 0.68 (95% CI, 0.60-0.75) and 0.66 (95% CI, 0.60-0.71), respectively. In contrast, among the 1089 women with screening mammograms (98 cases of BC within 10 years), the BCSC model had better calibration (0.94; 95% CI, 0.85-1.43) and discrimination (0.63; 95% CI, 0.56-0.71) at 10 years versus 5 years (calibration, 1.31; 95% CI, 0.94-2.25; discrimination, 0.59; 95% CI, 0.46-0.71) where discrimination was not different from chance. CONCLUSIONS: The BCSC and BBD-BC models were validated in the Mayo BBD cohort, although their performance differed by 5-year risk versus 10-year risk. Further enhancement of these models is needed to provide accurate BC risk estimates for women with BBD.

Stroma modifies relationships between risk factor exposure and age-related epithelial involution in benign breast.

Delayed age-related lobular involution has been previously associated with elevated breast cancer risk. However, intraindividual variability in epithelial involution status within a woman is undefined. We developed a novel measure of age-related epithelial involution, density of epithelial nuclei in epithelial areas using digital image analysis in combination with stromal characteristics (percentage of section area comprising stroma). Approximately 1800 hematoxylin and eosin stained sections of benign breast tissue were evaluated from 416 participants having breast surgery for cancer or benign conditions. Two to sixteen slides per woman from different regions of the breast were studied. Epithelial involution status varied within a woman and as a function of stromal area. Percentage stromal area varied between samples from the same woman (median difference between highest and lowest stromal area within a woman was 7.5%, but ranged from 0.01 to 86.7%). Restricting to women with at least 10% stromal area (N = 317), epithelial nuclear density decreased with age (-637.1 cells/mm2 per decade of life after age 40, p < 0.0001), increased with mammographic density (457.8 cells/mm2 per increasing BI-RADs density category p = 0.002), and increased non-significantly with recent parity, later age at first pregnancy, and longer and more recent oral contraceptive use. These associations were attenuated in women with mostly fat samples (<10% stroma (N = 99)). Thirty-one percent of women evaluated had both adequate stroma (≥10%) and mostly fat (<10% stroma) regions of breast tissue, with the probability of having both types increasing with the number breast tissue samplings. Several breast cancer risk factors are associated with elevated age-related epithelial content, but associations depend upon stromal context. Stromal characteristics appear to modify relationships between risk factor exposures and breast epithelial involution.

Adherence to Guidelines for Breast Surveillance in Breast Cancer Survivors.

Background: Guidelines recommend annual mammography after curative-intent treatment for breast cancer. The goal of this study was to assess contemporary patterns of breast imaging after breast cancer treatment. Methods: Administrative claims data were used to identify privately insured and Medicare Advantage beneficiaries with nonmetastatic breast cancer who had residual breast tissue (not bilateral mastectomy) after breast surgery between January 2005 and May 2015. We calculated the proportion of patients who had a mammogram, MRI, both, or neither during each of 5 subsequent 13-month periods. Multinomial logistic regression was used to assess associations between patient characteristics, healthcare use, and breast imaging in the first and fifth years after surgery. Results: A total of 27,212 patients were followed for a median of 2.9 years (interquartile range, 1.8-4.6) after definitive breast cancer surgery. In year 1, 78% were screened using mammography alone, 1% using MRI alone, and 8% using both tests; 13% did not undergo either. By year 5, the proportion of the remaining cohort (n=4,790) who had no breast imaging was 19%. Older age was associated with an increased likelihood of mammography and a decreased likelihood of MRI during the first and fifth years. Black race, mastectomy, chemotherapy, and no MRI at baseline were all associated with a decreased likelihood of both types of imaging. Conclusions: Even in an insured cohort, a substantial proportion of breast cancer survivors do not undergo annual surveillance breast imaging, particularly as time passes. Understanding factors associated with imaging in cancer survivors may help improve adherence to survivorship care guidelines.

Merkel Cell Carcinoma, Version 1.2018, NCCN Clinical Practice Guidelines in Oncology.

This selection from the NCCN Guidelines for Merkel Cell Carcinoma (MCC) focuses on areas impacted by recently emerging data, including sections describing MCC risk factors, diagnosis, workup, follow-up, and management of advanced disease with radiation and systemic therapy. Included in these sections are discussion of the new recommendations for use of Merkel cell polyomavirus as a biomarker and new recommendations for use of checkpoint immunotherapies to treat metastatic or unresectable disease. The next update of the complete version of the NCCN Guidelines for MCC will include more detailed information about elements of pathology and addresses additional aspects of management of MCC, including surgical management of the primary tumor and draining nodal basin, radiation therapy as primary treatment, and management of recurrence.

Tissue-based associations of mammographic breast density with breast stem cell markers.

BACKGROUND: Mammographic breast density is a well-established, strong breast cancer risk factor but the biology underlying this association remains unclear. Breast density may reflect underlying alterations in the size and activity of the breast stem cell pool. We examined, for the first time, associations of CD44, CD24, and aldehyde dehydrogenase family 1 member A1 (ALDH1A1) breast stem cell markers with breast density. METHODS: We included in this study 64 asymptomatic healthy women who previously volunteered for a unique biopsy study of normal breast tissue at the Mayo Clinic (2006-2008). Mammographically identified dense and non-dense areas were confirmed/localized by ultrasound and biopsied. Immunohistochemical analysis of the markers was performed according to a standard protocol and the staining was assessed by a single blinded pathologist. In core biopsy samples retrieved from areas of high vs. low density within the same woman, we compared staining extent and an expression score (the product of staining intensity and extent), using the signed rank test. All tests of statistical significance were two-sided. RESULTS: A total of 64, 28, and 10 women were available for CD44, CD24, and ALDH1A1 staining, respectively. For all three markers, we found higher levels of staining extent in dense as compared to non-dense tissue, though for CD24 and ALDH1A1 the difference did not reach statistical significance (CD44, 6.3% vs. 2.0%, p < 0.001; CD24, 8.0% vs. 5.6%, p = 0.10; and ALDH1A1, 0.5% vs. 0.3%, p = 0.12). The expression score for CD44 was significantly greater in dense as compared to non-dense tissue (9.8 vs.3.0, p < 0.001). CONCLUSIONS: Our findings suggest an increased presence and/or activity of stem cells in dense as compared to non-dense breast tissue.

Association between mammographic breast density and histologic features of benign breast disease.

BACKGROUND: Over 40% of women undergoing breast screening have mammographically dense breasts. Elevated mammographic breast density (MBD) is an established breast cancer risk factor and is known to mask tumors within the dense tissue. However, the association of MBD with high risk benign breast disease (BBD) is unknown. METHOD: We analyzed data for 3400 women diagnosed with pathologically confirmed BBD in the Mayo Clinic BBD cohort from 1985-2001, with a clinical MBD measure (either parenchymal pattern (PP) or Breast Imaging Reporting and Data Systems (BI-RADS) density) and expert pathology review. Risk factor information was collected from medical records and questionnaires. MBD was dichotomized as dense (PP classification P2 or DY, or BI-RADS classification c or d) or non-dense (PP classification N1 or P1, or BI-RADS classification a or b). Associations of clinical and histologic characteristics with MBD were examined using logistic regression analysis to estimate odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: Of 3400 women in the study, 2163 (64%) had dense breasts. Adjusting for age and body mass index (BMI), there were positive associations of dense breasts with use of hormone therapy (HT), lack of lobular involution, presence of atypical lobular hyperplasia (ALH), histologic fibrosis, columnar cell hyperplasia/flat epithelia atypia (CCH/FEA), sclerosing adenosis (SA), cyst, usual ductal hyperplasia, and calcifications. In fully adjusted multivariate models, HT (1.3, 95% CI 1.1-1.5), ALH (1.5, 95% CI 1.0-2.2), lack of lobular involution (OR 1.6, 95% CI 1.2-2.1, compared to complete involution), fibrosis (OR 2.2, 95% CI 1.9-2.6) and CCH/FEA (OR 1.3, 95% CI 1.0-1.6) remained significantly associated with high MBD. CONCLUSION: Our findings support an association between high risk BBD and high MBD, suggesting that risks associated with the latter may act early in breast carcinogenesis.

Flat Epithelial Atypia on Core Biopsy and Upgrade to Cancer: a Systematic Review and Meta-Analysis.

BACKGROUND: No consensus exists on whether flat epithelial atypia (FEA) diagnosed percutaneously should be surgically excised. A systematic review and meta-analysis of the frequency of upgrade to cancer or an atypical ductal hyperplasia (ADH) at surgical excision of FEA was performed. METHODS: Embase, MEDLINE, Scopus, and Web of Science databases from January 2003 to November 2015 were searched. The inclusion criteria required a manuscript in English with original data on FEA diagnosed percutaneously, data including the presence or absence of other concurrent high-risk lesions, and data including outcome of cancer at surgical excision. Studies were assessed for quality, and two reviewers extracted data. Random-effects meta-analysis was used to pool estimates. The impact of study-level characteristics was assessed by stratified meta-analysis and meta-regression. RESULTS: The inclusion criteria was met by 32 studies. A total of 1966 core needle biopsies showed pure FEA, and 1517 (77%) showed surgical excision. The proportions of patients with upgrade to cancer varied from 0 to 42%, with an overall pooled estimate of 11.1%. Heterogeneity was observed, with the greatest impact based on whether a study included cases of FEA diagnosed before 2003. With restriction of the investigation to 16 higher-quality studies, the cancer upgrade pooled estimate was 7.5% (95% confidence interval [CI], 5.4-10.4%), and the rate of invasive cancer was 3% (95% CI 1.9-4.5%). For upgrade to ADH, data from 22 studies including 937 patients were analyzed. The proportion of patients upgraded to ADH ranged from 0 to 60%, with a pooled estimate of 17.9% overall and 18.6% among high-quality studies. CONCLUSIONS: With patient management change potential for approximately 25% of patients, this analysis supports a general recommendation for surgical excision of FEA diagnosed by core biopsy.

Mammographic breast density and risk of breast cancer in women with atypical hyperplasia: an observational cohort study from the Mayo Clinic Benign Breast Disease (BBD) cohort.

BACKGROUND: Atypical hyperplasia (AH) and mammographic breast density (MBD) are established risk factors for breast cancer (BC), but their joint contributions are not well understood. We examine associations of MBD and BC by histologic impression, including AH, in a subcohort of women from the Mayo Clinic Benign Breast Disease Cohort. METHODS: Women with a diagnosis of BBD and mammogram between 1985 and 2001 were eligible. Histologic impression was assessed via pathology review and coded as non-proliferative disease (NP), proliferative disease without atypia (PDWA) and AH. MBD was assessed clinically using parenchymal pattern (PP) or BI-RADS criteria and categorized as low, moderate or high. Percent density (PD) was also available for a subset of women. BC and clinical information were obtained by questionnaires, medical records and the Mayo Clinic Tumor Registry. Women were followed from date of benign biopsy to BC, death or last contact. Standardized incidence ratios (SIRs) compared the observed number of BCs to expected counts. Cox regression estimated multivariate-adjusted MBD hazard ratios. RESULTS: Of the 6271 women included in the study, 1132 (18.0%) had low MBD, 2921 (46.6%) had moderate MBD, and 2218 (35.4%) had high MBD. A total of 3532 women (56.3%) had NP, 2269 (36.2%) had PDWA and 470 (7.5%) had AH. Over a median follow-up of 14.3 years, 528 BCs were observed. The association of MBD and BC risk differed by histologic impression (p-interaction = 0.03), such that there was a strong MBD and BC association among NP (p < 0.001) but non-significant associations for PDWA (p = 0.27) and AH (p = 0.96). MBD and BC associations for AH women were not significant within subsets defined by type of MBD measure (PP vs. BI-RADS), age at biopsy, number of foci of AH, type of AH (lobular vs. ductal) and body mass index, and after adjustment for potential confounding variables. Women with atypia who also had high PD (>50%) demonstrated marginal evidence of increased BC risk (SIR 4.98), but results were not statistically significant. CONCLUSION: We found no evidence of an association between MBD and subsequent BC risk in women with AH.

Extent of atypical hyperplasia stratifies breast cancer risk in 2 independent cohorts of women.

BACKGROUND: Women with atypical hyperplasia (AH) on breast biopsy have a substantially increased risk of breast cancer (BC). Here the BC risk for the extent and subtype of AH is reported for 2 separate cohorts. METHODS: All samples containing AH were included from 2 cohorts of women with benign breast disease (Mayo Clinic and Nashville). Histology review quantified the number of foci of atypical ductal hyperplasia (ADH) and atypical lobular hyperplasia (ALH). The BC risk was stratified for the number of AH foci within AH subtypes. RESULTS: The study included 708 Mayo AH subjects and 466 Nashville AH subjects. In the Mayo cohort, an increasing number of foci of AH was associated with a significant increase in the risk of BC both for ADH (relative risks of 2.61, 5.21, and 6.36 for 1, 2, and ≥3 foci, respectively; P for linear trend = .006) and for ALH (relative risks of 2.56, 3.50, and 6.79 for 1, 2, and ≥3 foci, respectively; P for linear trend = .001). In the Nashville cohort, the relative risks of BC for ADH were 2.70, 5.17, and 15.06 for 1, 2, and ≥3 foci, respectively (P for linear trend < .001); for ALH, the relative risks also increased but not significantly (2.61, 3.48, and 4.02, respectively; P = .148). When the Mayo and Nashville samples were combined, the risk increased significantly for 1, 2, and ≥3 foci: the relative risks were 2.65, 5.19, and 8.94, respectively, for ADH (P < .001) and 2.58, 3.49, and 4.97, respectively, for ALH (P = .001). CONCLUSIONS: In 2 independent cohort studies of benign breast disease, the extent of atypia stratified the long-term BC risk for ADH and ALH. Cancer 2016;122:2971-2978. © 2016 American Cancer Society.

Clinicopathologic features of breast cancers that develop in women with previous benign breast disease.

BACKGROUND: Women with benign breast disease (BBD) have an increased risk of developing breast cancer (BC). Nearly 30% of all BCs develop in women with prior BBD. Information regarding features of the expected number of BCs after BBD would enhance individualized surveillance and prevention strategies for these women. In the current study, the authors sought to characterize BCs developing in a large cohort of women with BBD. METHODS: The current study cohort included 13,485 women who underwent breast biopsy for mammographic or palpable concerns between 1967 and 2001. Biopsy slides were reviewed and classified as nonproliferative disease, proliferative disease without atypia, or atypical hyperplasia. BCs were identified by follow-up questionnaires, medical records, and Tumor Registry data. BC tissues were obtained and reviewed. RESULTS: With median follow-up of 15.8 years, 1273 women developed BC. The majority of BCs were invasive (81%), of which 61% were ductal, 13% were mixed ductal/lobular, and 14% were lobular. Approximately two-thirds of the BC cases were intermediate or high grade, and 29% were lymph node positive. Cancer characteristics were similar across the 3 histologic categories of BBD, with a similar frequency of ductal carcinoma in situ, invasive disease, tumor size, time to invasive BC, histologic type of BC, lymph node positivity, and human epidermal growth factor receptor 2 positivity. Women with atypical hyperplasia were found to have a higher frequency of estrogen receptor-positive BC (91%) compared with women with proliferative disease without atypia (80%) or nonproliferative disease (85%) (P = .02). CONCLUSIONS: A substantial percentage of all BCs develop in women with prior BBD. The majority of BCs after BBD are invasive tumors of ductal type, with a substantial number demonstrating lymph node positivity. Of all the BCs in the current study, 84% were estrogen receptor positive. Prevention therapy should be strongly encouraged in higher-risk women with BBD.

Low-Grade Malignant Proliferating Tricholemmal Tumor Associated With Occult Ductal Carcinoma In Situ of the Breast.

Malignant proliferating tricholemmal tumor (MPTT) is a rare adnexal neoplasm most commonly located on the scalp. We a 62-year-old woman who presented to her local physician with a palpable but not visible nodule of the left breast, initially diagnosed as squamous cell carcinoma. Histopathological evaluation of the reexcision specimen incidentally revealed ductal carcinoma in situ. On referral to our institution, the skin biopsy specimen was reviewed and interpreted as a low-grade MPTT. This patient and 2 previously reported cases of MPTT involving breast skin highlight presentation of a rare tumor at an unusual site and the potential for misdiagnosis as squamous cell carcinoma. Reexcision provided the unexpected benefit for our patient of early diagnosis of ductal carcinoma in situ not revealed by imaging.

Flat epithelial atypia and risk of breast cancer: A Mayo cohort study.

BACKGROUND: Based on its cytologic features, and its co-occurrence with atypical hyperplasia and breast cancer, flat epithelial atypia (FEA) has been proposed as a precursor lesion on the pathway to the development of breast cancer. It is often referred to as an "atypical" or high-risk lesion. However, to the authors' knowledge, the long-term risk of breast cancer in women with FEA is undefined. METHODS: Specimens with FEA were identified among excisional breast biopsies in the Mayo Clinic Benign Breast Disease Cohort, which includes 11,591 women who had benign biopsy findings at the Mayo Clinic in Rochester, Minnesota between 1967 and 2001. Breast cancer risk among subsets of patients with FEA and nonproliferative, proliferative, and atypical hyperplasia (AH) was assessed using standardized incidence ratios (SIRs) compared with the Iowa Surveillance, Epidemiology, and End Results registry. RESULTS: FEA was identified in 282 women (2.4%); 130 had associated AH (46%) and 152 (54%) were classified as having proliferative disease without atypia (PDWA). With median follow-up of 16.8 years, the SIR for breast cancer in patients with AH plus FEA was 4.74 (95% confidence interval [95% CI], 3.17-6.81) versus 4.23 (95% CI, 3.44-5.13) for those with AH without FEA (P = .59). The SIR for patients with PDWA plus FEA was 2.04 (95% CI, 1.23-3.19) versus 1.90 (95% CI, 1.72-2.09) for patients with PDWA without FEA (P = .76). CONCLUSIONS: FEA is an uncommon finding in women with benign breast disease. FEA does not appear to convey an independent risk of breast cancer beyond that of the associated PDWA or AH.

Complex fibroadenoma and breast cancer risk: a Mayo Clinic Benign Breast Disease Cohort Study.

The purpose of this study is to examine the breast cancer risk overall among women with simple fibroadenoma or complex fibroadenoma and to examine the association of complex fibroadenoma with breast cancer through stratification of other breast cancer risks. The study included women aged 18-85 years from the Mayo Clinic Benign Breast Disease Cohort who underwent excisional breast biopsy from 1967 through 1991. Within this cohort, women who had fibroadenoma were compared to women who did not have fibroadenoma. Breast cancer risk (observed versus expected) across fibroadenoma levels was assessed through standardized incidence ratios (SIRs) by using age- and calendar-stratified incidence rates from the Iowa Surveillance, Epidemiology, and End Results registry. Analyses were performed overall, within subgroups of involution status, with other demographic characteristics (age, year of biopsy, indication for biopsy, and family history), and with histologic characteristics, including overall impression [nonproliferative disease, proliferative disease without atypia (PDWA), or atypical hyperplasia]. Fibroadenoma was identified in 2136 women [noncomplex, 1835 (85.9%); complex, 301 (14.1%)]. SIR for noncomplex fibroadenoma was 1.49 (95% CI 1.26-1.74); for complex fibroadenoma, it was 2.27 (95% CI 1.63-3.10) (test for heterogeneity in SIR, P = .02). However, women with complex fibroadenoma were more likely to have other, concomitant high-risk histologic characteristics (e.g., incomplete involution and PDWA). In analyses stratified by involution status and PDWA, complex fibroadenoma was not an independent risk marker for breast cancer. Complex fibroadenoma does not confer increased breast cancer risk beyond other established histologic characteristics.