Petrina A Causer

North York General Hospital, North York, Ontario, Canada

Are you Petrina A Causer?

Claim your profile

Publications (34)211.93 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: This study investigates the use of a proposed vector machine formulation with application to dynamic contrast-enhanced magnetic resonance imaging examinations in the context of the computer-aided diagnosis of breast cancer. This paper describes a method for generating feature measurements that characterize a lesion's vascular heterogeneity as well as a supervised learning formulation that represents an improvement over the conventional support vector machine in this application. Spatially varying signal-intensity measures were extracted from the examinations using principal components analysis and the machine learning technique known as the support vector machine (SVM) was used to classify the results. An alternative vector machine formulation was found to improve on the results produced by the established SVM in randomized bootstrap validation trials, yielding a receiver-operating characteristic curve area of 0.82 which represents a statistically significant improvement over the SVM technique in this application.
    Journal of Digital Imaging 07/2013; · 1.10 Impact Factor
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: 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. 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. 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. 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.
    Cancer Epidemiology Biomarkers &amp Prevention 06/2012; 21(9):1458-68. · 4.56 Impact Factor
  • Cancer Epidemiology Biomarkers &amp Prevention 06/2012; · 4.56 Impact Factor
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: The addition of breast magnetic resonance imaging (MRI) to screening mammography for women with BRCA mutations significantly increases sensitivity, but there is little data on clinical outcomes. We report screening performance, cancer stage, distant recurrence rate, and breast cancer-specific mortality in our screening study. From 1997 to 2009, 496 women aged 25 to 65 years with a known BRCA1/2 mutation, of whom 380 had no previous cancer history, were enrolled in a prospective screening trial that included annual MRI and mammography. In 1847 screening rounds, 57 cancers were identified (53 screen-detected, 1 interval, and 3 incidental at prophylactic mastectomy), of which 37 (65%) were invasive. Sensitivity of MRI vs mammography was 86% vs 19% over the entire study period (P<0.0001), but was 74% vs 35% from 1997 to 2002 (P=0.02) and 94% vs 9% from 2003 to 2009 (P<0.0001), respectively. The relative sensitivities of MRI and mammography did not differ by mutation, age, or invasive vs non-invasive disease. Of the incident cancers, 97% were Stage 0 or 1. Of 28 previously unaffected women diagnosed with invasive cancer, 1 BRCA1 mutation carrier died following relapse of a 3 cm, node-positive breast cancer diagnosed on her first screen at age 48 (annual breast cancer mortality rate=0.5%). Three patients died of other causes. None of the 24 survivors has had a distant recurrence at a median follow-up of 8.4 years since diagnosis. Magnetic resonance imaging surveillance of women with BRCA1/2 mutations will detect the majority of breast cancers at a very early stage. The absence of distant recurrences of incident cancers to date is encouraging. However, longer follow-up is needed to confirm the safety of breast surveillance.
    British Journal of Cancer 05/2012; 107(1):24-30. · 5.08 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: To achieve high-quality unilateral supine breast magnetic resonance imaging (MRI) as a step to facilitate image aiding of clinical applications, which are often performed in the supine position. Contrast-enhanced breast MRI is a powerful tool for the diagnosis of cancer. However, prone patient positioning typically used for breast MRI hinders its use for image aiding. A fixture and a flexible four-element receive coil were designed for patient-specific shaping and placement of the coil in close conformity to the supine breast. A 3D spoiled gradient sequence was modified to incorporate compensation of respiratory motion. The entire setup was tested in volunteer experiments and in a pilot patient study. The flexible coil design and the motion compensation produced supine breast MR images of high diagnostic value. Variations in breast shape and in tissue morphology within the breast were observed between a supine and a diagnostic prone MRI of a patient. The presented supine breast MRI achieved an image quality comparable to diagnostic breast MRI. Since supine positioning is common in many clinical applications such as ultrasound-guided breast biopsy or breast-conserving surgery, the registration of the supine images will aid these applications.
    Journal of Magnetic Resonance Imaging 09/2011; 34(5):1212-7. · 2.57 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: OBJECTIVE: The addition of magnetic resonance imaging (MRI) to mammography for surveillance of women with BRCA mutations significantly increases sensitivity but lowers specificity. This study aimed to examine whether MRI surveillance, and particularly recall, is associated with increased anxiety, depression, or breast cancer worry/distress. METHODS: Women with BRCA mutations in an MRI surveillance study were invited to complete: Hospital Anxiety and Depression Scale (HADS), Lerman's Breast Cancer Worry Scale, Breast Cancer Worry Interference Scale, and a quality of life rating at 3 time points: 1-2 weeks before (T1), 4-6 weeks after (T2) and 6 months after their annual surveillance (T3). Repeated measures analyses were performed over the 3 time points for recalled and non-recalled women. RESULTS: 55 women (30 BRCA1, 25 BRCA2) completed study instruments at T1 and T2, and 48 at T3. Eighteen women (32%) were recalled for additional imaging. At T1, 27 women (49%) were above HADS threshold for "possible cases" for anxiety (score≥8). Recalled (but not non-recalled) women had a significant increase of HADS anxiety at T2 which dropped to below baseline by T3. No group differences were observed in terms of change over time in other quantitative psychological measures. CONCLUSIONS: While breast MRI surveillance did not have a detrimental psychological impact on women with a BRCA1 or BRCA2 mutation, recalling these very high-risk women for further imaging after a false positive MRI scan temporarily increased their global anxiety.
    Breast (Edinburgh, Scotland) 05/2011; 20(5):424-30. · 2.09 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: To compare the underestimation of ductal carcinoma in situ (DCIS) vs DCIS with "possible invasion" at breast biopsy and to determine if any factors related to clinical indication, imaging abnormality, biopsy, or DCIS-grade affected the likelihood of underestimation. Of 3836 consecutive lesions that were biopsied by using a 14-gauge needle, 117 lesions revealed DCIS. Surgical pathology results of invasive carcinoma were compared with needle biopsy results of DCIS or DCIS with possible invasion. Clinical indication, imaging abnormality, biopsy guidance modality, sample number, and histologic grade were recorded. Yates corrected χ(2) and Fisher exact tests were used to determine differences between groups. A total of 101 lesions were DCIS and 16 were DCIS with possible invasion at biopsy. Thirty-six of 117 lesions (31%) revealed invasive carcinoma at resection pathology. Invasive carcinoma was present more often when DCIS with possible invasion was diagnosed compared with pure DCIS (7/16 [44%] vs 29/101 [29%], P = .36). No factor, including clinical indication, imaging abnormality, biopsy guidance method, sample number, or grade, was found to significantly affect the likelihood of underestimation for lesions diagnosed as DCIS vs DCIS with "possible invasion." The likelihood of pure DCIS underestimation significantly increased when lesions were high grade compared with either intermediate or low grade (18/44 [41%] vs 9/44 [21%] vs 2/10 [20%], P = .03). For lesions biopsied by using a 14-gauge needle, there is a trend towards underestimation of the presence of invasive carcinoma when pathology reveals DCIS with possible invasion compared with pure DCIS. High-grade DCIS was significantly more likely to be underestimated.
    Canadian Association of Radiologists Journal 05/2011; 63(2):146-52. · 0.43 Impact Factor
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: 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. 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. 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). Annual surveillance with MRI is associated with a significant reduction in the incidence of advanced-stage breast cancer in BRCA1 and BRCA2 carriers.
    Journal of Clinical Oncology 03/2011; 29(13):1664-9. · 18.04 Impact Factor
  • Petrina A Causer
    [show abstract] [hide abstract]
    ABSTRACT: Breast magnetic resonance imaging (MRI) is indisputably the highest sensitivity test available to detect breast cancer, revealing more extensive cancer in the ipsilateral and otherwise occult cancer in the contralateral breasts when used before surgery. The use of preoperative breast MRI has become somewhat controversial, because the clinical benefit of the heightened detection provided by MRI has been questioned in the context of multidisciplinary breast cancer treatment, relatively low local recurrence, and metachronous contralateral cancer rates. Also, MRI detection rates have been compared with the high rates reported in the pathology literature. The emerging clinical outcome literature is showing conflicting results to demonstrating actual overall benefit. Critical review of this literature reveals several misconceptions about MRI detection rates and limitations of many of the published outcome studies to date, which render the results not necessarily generalizable to contemporary optimized breast MRI practices. This article addresses some of the misconceptions raised by critics, provides a critical review of the clinical outcome literature, reviews patient subgroups anticipated to have the highest yield when using preoperative MRI, makes recommendations for optimizing breast MRI practice, and suggests areas for potential future research.
    Canadian Association of Radiologists Journal 02/2011; 62(1):8-14. · 0.43 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: Breast MRI is often used for surveillance of breast cancer (BC) survivors despite the lack of evidence in this population. We surveyed younger BC survivors to evaluate their willingness to participate in a randomized controlled trial (RCT) of annual digital mammography with or without MRI. Median age of the 348 participants was 51 years; 45% had undergone diagnostic MRI. 22% continued to have surveillance MRI. 58% agreed to consider participating in the proposed RCT; 16% remained neutral. An RCT of MRI surveillance for BC survivors <age 60 is still feasible at centres where annual MRI is not yet routinely recommended.
    Breast (Edinburgh, Scotland) 02/2011; 20(1):96-8. · 2.09 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: Although magnetic resonance imaging (MRI) is much more sensitive than mammography for detecting early invasive breast cancer, in many high-risk screening studies MRI was less sensitive than mammography for detecting ductal carcinoma in situ (DCIS). We reviewed our experience detecting DCIS in our single center study of annual MRI, mammography, ultrasound and clinical breast examination (CBE) for screening very high-risk women. All cases of DCIS±microinvasion and invasive cancer were compared in two time frames: before (period A) and after (period B) July 2001-when we acquired expertise in the detection of DCIS with MRI-with respect to patient demographics, method of detection, and rates of detection of invasive cancer and DCIS. In period A there were 15 cases (3.1% of 486 screens) in 223 women, of which 2 (13%) were DCIS-one with microinvasion-neither detected by MRI. In period B there were 29 cases (3.3% of 877 screens) in 391 women, of which 10 (34%) were DCIS±microinvasion (p=0.04), all 10 detected by MRI but only one by mammography. No DCIS cases were detected by ultrasound or CBE. Specificity was lower in period B than in period A but acceptable. The ability to detect DCIS with screening MRI improves significantly with experience. MRI-guided biopsy capability is essential for a high-risk screening program. In experienced centers the increased sensitivity of MRI relative to mammography is at least as high for DCIS as it is for invasive breast cancer.
    The Breast Journal 01/2011; 17(1):9-17. · 1.83 Impact Factor
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: Accurate assessment of residual disease after neo-adjuvant chemotherapy (NEC) for women with locally advanced and inflammatory breast cancer (LABC) is critical for planning surgery. The study's purpose was to prospectively determine the optimal method (clinical examination (CE), mammogram (MG), and magnetic resonance imaging (MRI)) for assessing residual disease after NEC for women with LABC. Women with LABC who received NEC and surgery were enrolled. Patient demographics, tumor size as measured by CE, MG, and MRI both before and after NEC, and final pathologic size of tumor were collected. Response to NEC was calculated using RECIST criteria. Paired t-tests and the Pearson correlation were used to compare tumor size on CE, MG, MRI, and final pathology. Forty-eight women with 50 LABC were recruited. Mean pre-NEC tumor size was 8.2, 5.1, and 6.2 cm on CE, MG, and MRI. Mean post-NEC tumor size was 2.4, 4.3, 3.9, and 3.6 cm on CE, MG, MRI, and final pathology. The Pearson correlation co-efficient between post-NEC measurements and pathology was 0.63 (CE), 0.15 (MG), and 0.49 (MRI). We found that there was limited correlation between the extent of residual disease after NEC for patients with LABC as assessed by CE, MG, and MRI as compared to final pathology.
    Journal of Surgical Oncology 06/2010; 101(7):604-10. · 2.64 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: To evaluate the sensitivity and specificity of magnetic resonance imaging (MRI) computer-aided detection (CAD) for breast MRI screen-detected lesions recommended for biopsy in a high-risk population. Fifty-six consecutive Breast Imaging Reporting and Data System (BI-RADS) 3-5 lesions with histopathological correlation [nine invasive cancers, 13 ductal carcinoma in situ (DCIS) and 34 benign] were retrospectively evaluated using a breast MRI CAD prototype (CAD-Gaea). CAD evaluation was performed separately and in consensus by two radiologists specializing in breast imaging, blinded to the histopathology. Thresholds of 50, 80, and 100% and delayed enhancement were independently assessed with CAD. Lesions were rated as malignant or benign according to threshold and delayed enhancement only and in combination. Sensitivities, specificities, and negative predictive values (NPV) were determined for CAD assessments versus pathology. Initial MRI BI-RADS interpretation without CAD versus CAD assessments were compared using paired binary diagnostic tests. Threshold levels for lesion enhancement were: 50% to include all malignant (and all benign) lesions; and 100% for all invasive cancer and high-grade DCIS. Combined use of threshold and enhancement patterns for CAD assessment was best (73% sensitivity, 56% specificity and 76% NPV for all cancer). Sensitivities and NPV were better for invasive cancer (100%/100%) than for all malignancies (54%/76%). Radiologists' MRI interpretation was more sensitive than CAD (p=0.05), but less specific (p=0.001) for cancer detection. The breast MRI CAD system used could not improve the radiologists' accuracy for distinguishing all malignant from benign lesions, due to the poor sensitivity for DCIS detection.
    Clinical radiology 12/2009; 64(12):1166-74. · 1.65 Impact Factor
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: To evaluate the effect that variations in the enhancement threshold have on the diagnostic accuracy of two computer-aided detection (CAD) systems for magnetic resonance based breast cancer screening. Informed consent was obtained from all patients participating in cancer screening and this study was approved by the participating institution's review board. This retrospective study was nested in a prospective, single-institution, high-risk, breast screening study involving dynamic contrast-enhanced magnetic resonance imaging. Only those screening examinations (n = 223) for which a histopathological diagnosis was available were included. Two CAD methods were performed: the signal enhancement ratio (SER) and support vector machines (SVMs). Statistical analysis was performed by tracking changes in each CAD test's diagnostic accuracy (eg, receiver-operating characteristic [ROC] curve area, maximum possible sensitivity) with changes in the enhancement threshold. The enhancement threshold plays a significant role in affecting a CAD test's potential sensitivity, ROC curve area, and number of assumed true and false-positive predictions per cancerous examination. A high threshold can also limit the CAD-based detection of the full size of a lesion. Enhancement thresholds can limit a CAD test's ability to diagnose a lesion's full size and as such should not be raised above 60%. The clinically used SER method exhibits a high rate of false positives at low enhancement thresholds and as such the threshold should not be set lower than 50%. The SVM method yielded better results in our study than the SER method at clinically realistic enhancement thresholds.
    Academic radiology 07/2009; 16(9):1064-9. · 2.09 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: Breast magnetic resonance imaging (MRI) may provide a more accurate assessment of synchronous contralateral breast cancer in select cohorts of patients. The utility of this imaging technique for detecting synchronous contralateral breast cancers in patients with locally advanced breast cancer (LABC) has not previously been described. We report our experience in assessing contralateral disease in a cohort of women with LABC who had clinical assessment, mammography, ultrasound, and MRI prior to neo-adjuvant therapy. Patients, who presented with LABC, stage IIB (T3N0), stage III A/B, were identified from a prospectively kept data base at a single tertiary care centre between November 2001 and August 2005. Charts were retrospectively reviewed and demographic, imaging and pathologic variables were abstracted. One hundred and one female patients with LABC were identified (median age 49). One hundred of 101 patients presented with a clinically obvious LABC. Three patients had LABC that was not visualized mammographically but was detected on ultrasound and MRI. Seventeen of 101 patients (17%) had contralateral imaging findings that required biopsy for diagnosis. Of the contralateral biopsies, 41% (7/17) were malignant. These malignant lesions were identified clinically in 4/7 patients, on 7/7 ultrasounds, 7/7 mammograms, and 5/5 MRI. Overall, 7% (7/101) patients had malignant synchronous contralateral disease. In our LABC patient cohort, 7% of patients presented with malignant contralateral disease. The incidence of contralateral disease in women with LABC is comparable with patients who present with early stage breast cancer. No single screening technique, ultrasound, mammogram or MRI, appeared to be superior for identifying contralateral synchronous malignancy.
    The Breast Journal 11/2008; 14(6):556-61. · 1.83 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: OBJECTIVE: Sonographic correlation of breast MRI findings is often challenging. We present a preliminary in vivo feasibility study evaluating the degree of error of a new MRI-sonography coregistration system for showing MRI and sonographically visible breast lesions. CONCLUSION: In 10 patients with 13 lesions, the system was found to be an accurate means for targeting sonography to MRI of the same breast lesions.
    American Journal of Roentgenology 11/2008; 191(4):1203-7. · 2.90 Impact Factor
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: Early detection of breast cancer is one of the most important factors in determining prognosis for women with malignant tumors. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has been shown to be the most sensitive modality for screening high-risk women. Computer-aided diagnosis (CAD) systems have the potential to assist radiologists in the early detection of cancer. A key component of the development of such a CAD system will be the selection of an appropriate classification function responsible for separating malignant and benign lesions. The purpose of this study is to evaluate the effects of variations in temporal feature vectors and kernel functions on the separation of malignant and benign DCE-MRI breast lesions by support vector machines (SVMs). We also propose and demonstrate a classifier visualization and evaluation technique. We show that SVMs provide an effective and flexible framework from which to base CAD techniques for breast MRI, and that the proposed classifier visualization technique has potential as a mechanism for the evaluation of classification solutions.
    IEEE transactions on medical imaging. 06/2008; 27(5):688-96.
  • [show abstract] [hide abstract]
    ABSTRACT: A sensitive and acceptable screening regimen for women at high risk for breast cancer is essential. Contrast-enhanced magnetic resonance imaging (MRI) of the breast is highly sensitive for diagnosis of breast cancer but has variable specificity. To summarize the sensitivity, specificity, likelihood ratios, and posttest probability associated with adding MRI to annual mammography screening of women at very high risk for breast cancer. English-language literature search of the MEDLINE, EMBASE, and Cochrane databases from January 1995 to September 2007, supplemented by hand searches of pertinent articles. Prospective studies published after 1994 in which MRI and mammography (with or without additional tests) were used to screen women at very high risk for breast cancer. Methods and potential biases of studies were assessed by 2 reviewers, and data were extracted and entered into 2 x 2 tables that compared American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) scores of MRI plus mammography, mammography alone, or MRI alone with results of breast tissue biopsies. Eleven relevant, prospective, nonrandomized studies that ranged from small single-center studies with only 1 round of patient screening to large multicenter studies with repeated rounds of annual screening were identified. Characteristics of women that varied across study samples included age range, history of breast cancer, and BRCA1 or BRCA2 mutation status. Studies used dynamic contrast-enhanced MRI with axial or coronal plane images (European studies) or sagittal images (North American studies) that were usually interpreted without knowledge of mammography results. The summary negative likelihood ratio and the probability of a BI-RADS-suspicious lesion (given negative test findings and assuming a 2% pretest probability of disease) were 0.70 (95% CI, 0.59 to 0.82) and 1.4% (CI, 1.2% to 1.6%) for mammography alone and 0.14 (CI, 0.05 to 0.42) and 0.3% (CI, 0.1% to 0.8%) for the combination of MRI plus mammography, using a BI-RADS score of 4 or higher as the definition of positive. Differences in patient population, center experience, and criteria for positive screening results led to between-study heterogeneity. Data on patients with nonfamilial high risk were limited, and no data were available on recurrence or survival. Screening with both MRI and mammography might rule out cancerous lesions better than mammography alone in women who are known or likely to have an inherited predisposition to breast cancer.
    Annals of internal medicine 06/2008; 148(9):671-9. · 13.98 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: 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. 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) <or=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 Fisher's exact test. 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. It is necessary to add MRI to mammography for screening women with BRCA mutations even if their breast density is low.
    Cancer Epidemiology Biomarkers &amp Prevention 03/2008; 17(3):706-11. · 4.56 Impact Factor
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: 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. 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. 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 < or =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 < or =40 years compared with 9 mm in older patients (P = 0.003); tumors were largest in young women with BRCA1 mutations. Tumors grow quickly in women with BRCA1 mutations and in young women. Age and risk group should be taken into account in screening protocols.
    Clinical Cancer Research 12/2007; 13(24):7357-62. · 7.84 Impact Factor

Publication Stats

1k Citations
211.93 Total Impact Points

Institutions

  • 2013
    • North York General Hospital
      North York, Ontario, Canada
  • 2005–2011
    • Sunnybrook Health Sciences Centre
      • • Department of Medical Imaging
      • • Division of Medical Oncology and Hematology
      Toronto, Ontario, Canada
    • University of Toronto
      • • Department of Surgery
      • • Department of Medical Imaging
      Toronto, Ontario, Canada