Kimberley Hill

Prospective Study of Breast Cancer Incidence in Women With a BRCA1 or BRCA2 Mutation Under Surveillance With and Without Magnetic Resonance Imaging

PURPOSE The sensitivity of magnetic resonance imaging (MRI) for breast cancer screening exceeds that of mammography. If MRI screening reduces mortality in women with a BRCA1 or BRCA2 mutation, it is expected that the incidence of advanced-stage breast cancers should be reduced in women undergoing MRI screening compared with those undergoing conventional screening. PATIENTS AND METHODS We followed 1,275 women with a BRCA1 or BRCA2 mutation for a mean of 3.2 years. In total, 445 women were enrolled in an MRI screening trial in Toronto, Ontario, Canada, and 830 were in the comparison group. The cumulative incidences of ductal carcinoma in situ (DCIS), early-stage, and late-stage breast cancers were estimated at 6 years in the cohorts. RESULTS There were 41 cases of breast cancer in the MRI-screened cohort (9.2%) and 76 cases in the comparison group (9.2%). The cumulative incidence of DCIS or stage I breast cancer at 6 years was 13.8% (95% CI, 9.1% to 18.5%) in the MRI-screened cohort and 7.2% (95% CI, 4.5% to 9.9%) in the comparison group (P = .01). The cumulative incidence of stages II to IV breast cancers was 1.9% (95% CI, 0.2% to 3.7%) in the MRI-screened cohort and 6.6% (95% CI, 3.8% to 9.3%) in the comparison group (P = .02). The adjusted hazard ratio for the development of stages II to IV breast cancer associated with MRI screening was 0.30 (95% CI, 0.12 to 0.72; P = .008). CONCLUSION Annual surveillance with MRI is associated with a significant reduction in the incidence of advanced-stage breast cancer in BRCA1 and BRCA2 carriers.

BRCA1 mutation and young age predict fast breast cancer growth in the Dutch, United Kingdom, and Canadian magnetic resonance imaging screening trials

Purpose: Magnetic resonance imaging (MRI) screening enables early detection of breast cancers in women with an inherited predisposition. Interval cancers occurred in women with a BRCA1 mutation, possibly due to fast tumor growth. We investigated the effect of a BRCA1 or BRCA2 mutation and age on the growth rate of breast cancers, as this may influence the optimal screening frequency. Experimental Design: We reviewed the invasive cancers from the United Kingdom, Dutch, and Canadian MRI screening trials for women at hereditary risk, measuring tumor size at diagnosis and on preceding MRI and/or mammography. We could assess tumor volume doubling time (DT) in 100 cancers. Results: Tumor DT was estimated for 43 women with a BRCA1 mutation, 16 women with a BRCA2 mutation, and 41 women at high risk without an identified mutation. Growth rate slowed continuously with increasing age (P = 0.004). Growth was twice as fast in BRCA1 (P = 0.003) or BRCA2 (P = 0.03) patients as in high-risk patients of the same age. The mean DT for women with BRCA1/2 mutations diagnosed at ages ≤40, 41 to 50, and >50 years was 28, 68, and 81 days, respectively, and 83, 121, and 173 days, respectively, in the high-risk group. Pathologic tumor size decreased with increasing age (P = 0.001). Median size was 15 mm for patients ages ≤40 years compared with 9 mm in older patients (P = 0.003); tumors were largest in young women with BRCA1 mutations. Conclusion: Tumors grow quickly in women with BRCA1 mutations and in young women. Age and risk group should be taken into account in screening protocols.

Differences in Natural History between Breast Cancers in BRCA1 and BRCA2 Mutation Carriers and Effects of MRI Screening-MRISC, MARIBS, and Canadian Studies Combined

Background: It is recommended that BRCA1/2 mutation carriers undergo breast cancer screening using MRI because of their very high cancer risk and the high sensitivity of MRI in detecting invasive cancers. Clinical observations suggest important differences in the natural history between breast cancers due to mutations in BRCA1 and BRCA2, potentially requiring different screening guidelines. Methods: Three studies of mutation carriers using annual MRI and mammography were analyzed. Separate natural history models for BRCA1 and BRCA2 were calibrated to the results of these studies and used to predict the impact of various screening protocols on detection characteristics and mortality. Results: BRCA1/2 mutation carriers (N = 1,275) participated in the studies and 124 cancers (99 invasive) were diagnosed. Cancers detected in BRCA2 mutation carriers were smaller [80% ductal carcinoma in situ (DCIS) or ≤10 mm vs. 49% for BRCA1, P < 0.001]. Below the age of 40, one (invasive) cancer of the 25 screen-detected cancers in BRCA1 mutation carriers was detected by mammography alone, compared with seven (three invasive) of 11 screen-detected cancers in BRCA2 (P < 0.0001). In the model, the preclinical period during which cancer is screen-detectable was 1 to 4 years for BRCA1 and 2 to 7 years for BRCA2. The model predicted breast cancer mortality reductions of 42% to 47% for mammography, 48% to 61% for MRI, and 50% to 62% for combined screening. Conclusions: Our studies suggest substantial mortality benefits in using MRI to screen BRCA1/2 mutation carriers aged 25 to 60 years but show important clinical differences in natural history. Impact: BRCA1 and BRCA2 mutation carriers may benefit from different screening protocols, for example, below the age of 40. Cancer Epidemiol Biomarkers Prev; 21(9); 1458–68. ©2012 AACR.

Is mammography adequate for screening women with inherited BRCA mutations and low breast density

Background: Several observational studies have shown that magnetic resonance imaging (MRI) is significantly more sensitive than mammography for screening women over age 25 at high risk for hereditary breast cancer; however, MRI is more costly and less specific than mammography. We sought to determine the extent to which the low sensitivity of mammography is due to greater breast density. Methods: Breast density was evaluated for all patients on a high-risk screening study who were diagnosed with breast cancer between November 1997 and July 2006. Density was measured in two ways: qualitatively using the four categories characterized by the Breast Imaging Reporting and Data System and quantitatively using a computer-aided technique and classified as (a) ≤10%, (b) 11% to 25%, (c) 26% to 50%, and (d) >50% density. Comparison of sensitivity of mammography (and MRI) for each individual density category and after combining the highest two and lowest two density categories was done using Fishers exact test. Results: A total of 46 breast cancers [15 ductal carcinoma in situ (DCIS) and 31 invasive] were diagnosed in 45 women (42 with BRCA mutations). Mean age was 48.3 (range, 32-68) years. Overall, sensitivity of mammography versus MRI was 20% versus 87% for DCIS and 26% versus 90% for invasive cancer. There was a trend towards greater mammographic sensitivity for invasive cancer in women with fattier breasts compared with those with greater breast density (37-43% versus 8-12%; P = 0.1), but this trend was not seen for DCIS. Conclusion: It is necessary to add MRI to mammography for screening women with BRCA mutations even if their breast density is low. (Cancer Epidemiol Biomarkers Prev 2008;17(3):706–11)

Is Mammographic Breast Density a Breast Cancer Risk Factor in Women With BRCA Mutations

PURPOSE Increased mammographic breast density is well recognized as a breast cancer risk factor in the general population. However, it is unclear whether it is a risk factor in women with BRCA mutations. We present the results of a nested case-control screening study investigating the relationship between breast density and breast cancer incidence in this population. PATIENTS AND METHODS Women ages 25 to 65 years with known BRCA mutations were enrolled onto a single-center, high-risk breast cancer screening program. Using a computer-aided technique (Cumulus), quantitative percentage density (PD) was measured for each participant on her baseline mammogram by a single, blinded observer. RESULTS Between November 1997 and March 2008, 462 women (mean age, 44 years; 245 BRCA1 and 217 BRCA2) were screened and 50 breast cancers were diagnosed (38 invasive, 12 ductal carcinoma in situ [DCIS]). Density was not measured in 40 women of whom four developed cancer (three invasive, one DCIS). Mean PD (+/- standard deviation [SD]) for 376 women who did not develop breast cancer was 34% (23) compared with 31% (21) for 46 women with cancer (P = .51). Logistic regression model of breast cancer incidence and PD revealed an odds ratio of 0.99 (+/- 0.01 SD) for a one-unit increase in PD (P = .44). Results remained nonsignificant in multivariate analysis, as well as when women with pure DCIS were excluded. CONCLUSION Increased mammographic breast density is not associated with higher breast cancer incidence in women with BRCA mutations. On the basis of these findings, density should not be considered a factor for these women in decision making regarding prophylactic surgery or chemoprevention.

Breast Cancers Detected with Imaging Screening in the BRCA Population: Emphasis on MR Imaging with Histopathologic Correlation

The benefit of screening with breast magnetic resonance (MR) imaging for certain patient populations at high risk for breast cancer, most notably patients with a genetic mutation in the BRCA1 or BRCA2 gene, has been established in numerous studies and is now becoming part of routine clinical practice. Despite the lower sensitivity of mammography compared with that of MR imaging, the former remains the standard of care for screening any patient population. In the BRCA1 and BRCA2 populations, the inferior sensitivity and specificity of ultrasonography (US) limit its role as a screening tool, but US remains a vital diagnostic tool because of its ability to provide guidance for biopsy of many suspicious lesions detected with MR imaging. Important features of a screening program with breast MR imaging include the following: optimization of the MR imaging technique, an awareness of the imaging features of invasive and noninvasive breast cancers detected with MR imaging, an understanding of the limitations of the various imaging modalities in both the initial screening and subsequent diagnostic work-up evaluations, and the requirement for MR imaging-guided biopsy.

Reasons for risk-reducing mastectomy versus MRI-screening in a cohort of women at high hereditary risk of breast cancer.

OBJECTIVE To determine the reasons that motivate women in a cohort of women under intensive surveillance for breast cancer to undergo risk-reducing mastectomy (RRM). PATIENTS AND METHODS Women with a BRCA1 or BRCA2 mutation who were enrolled in an MRI-based breast screening study were eligible to participate in this survey. A self-administered questionnaire was given to women who did, and who did not terminate annual MRI-based surveillance in order to undergo RRM. The questionnaire included information on family history, risk perception and satisfaction with screening. In addition, women were asked to provide the principal reason for their choice of having preventive surgery or not, and were asked about their satisfaction with this choice. RESULTS 246 women without breast cancer participated in the study. Of these, 39 women (16%) elected to have RRM at some point after initiating screening. Although women who had a mother or sister with breast cancer were more likely to opt for RRM than were women with no affected first-degree relative (21% versus 10%) this did not reach statistical significance. Women who perceived their breast cancer risk to be greater than 50% were more likely to opt for RRM than were women who estimated their risk to be less than 50% (19% versus 6%). Fear of cancer was the most common reason cited for choosing to have RRM (38% of respondents) followed by having had a previous cancer, (25%), then concern over their children (16%). CONCLUSION Among women with a BRCA mutation who are enrolled in an MRI-based screening program, a high perception of personal breast cancer risk and a history of breast cancer in a first-degree relative are predictors of the decision to have RRM.

The Attitudes of Women with BRCA1 and BRCA2 Mutations toward Clinical Breast Examinations and Breast Self-Examinations

AIMS In screening studies of women with BRCA mutations, magnetic resonance imaging (MRI) plus mammography has >90% sensitivity for detecting breast cancer, with negligible benefit from the addition of breast self-examination (BSE) or clinical breast examination (CBE). Yet CBE is still frequently recommended, and BSE is encouraged for these women. We sought to determine the attitudes of high-risk women toward CBE and BSE. METHODS Between November 2005 and May 2006, 137 women with BRCA mutations participating in a screening study consisting of annual MRI and mammography plus semiannual CBE were asked to complete a mailed Likert-type questionnaire. RESULTS Of the 94 (67%) respondents, mean age 47 (range 28-67), 94% strongly agreed or agreed that CBE was an important way to detect breast cancer, and almost all believed it provided an important connection to the healthcare team. Only 10% said it increased anxiety. Of the 71 (77%) who performed BSE at least occasionally, 53 thought that regular BSE gave them a sense of control over their own health. Of the 21(23%) who did not practice BSE at all, only 3 did not believe that BSE was helpful, and it made 9 more worried about breast cancer CONCLUSIONS Although CBE adds little to cancer detection rates in women with BRCA mutations screened with MRI, the majority of these women considered CBE to be reassuring and an important means of connecting with the healthcare team. Compliance with BSE was only moderate, but it gave a significant proportion of women a greater sense of control.

Can Bilateral Asymmetry Analysis of Breast MR Images Provide Additional Information for Detection of Breast Diseases

This paper presents a new method for bilateral asymmetry analysis of breast MR images that uses directional statistics of the breast parenchymal edges, obtained from a multiresolution local energy edge detector, and image texture information derived from local energy maps, obtained by using a bank of log-Gabor filters. Classification of MRI scans into cancer and non-cancer categories was performed by linear discriminant analysis and the leave-one-out methodology. A total of 40 cases, 20 normal/benign (BI-RADS 1 and 2) and 20 malignant, taken from a high risk screening population,were used in this pilot study. Average classification accuracy of 70%(k=0.45 +- 0.14) with sensitivity and specificity of 75%and 65%, respectively, was achieved. The results obtained support the idea that bilateral asymmetry analysis of breast MR images can provide additional information for detection of breast tissue changes arising from diseases.