Abstract P6-13-01: MRI breast cancer screening compared to mammography in women with a familial risk: A multicenter randomized controlled trial

Background: Screening guidelines for women with a family history of breast cancer without a known causative gene mutation differ per country. No randomized controlled trial has been performed to assess the optimal screening strategy for these women.

Methods: In twelve centers, 1355 women aged 30–55 years with a cumulative lifetime risk of ≥20% without a BRCA1/2 mutation were randomized into two arms. From January 2011 until December 2017, women in the MRI-arm received yearly MRI-screening, clinical breast examination (CBE), and mammography every other year; and in the Mx-arm yearly mammography and CBE. Outcomes were number and stage of detected breast cancers, sensitivity, specificity and positive predictive value, and stratified by screening round and by mammographic density.

Results: After on average 4.3 screening rounds per woman, in the MRI-arm (N=675) compared to the Mx-arm (N=680) more breast cancers were detected (41 versus 14, p<0.001), invasive cancers were smaller (median size 8 versus 17 mm, p=0.006) and less often node positive (20% versus 71.4%, p=0.019)(Table). In the MRI-arm, sensitivity was slightly higher (95.1% versus 92.9%, p=1), and specificity significantly lower (82% versus 90.1%, p<0.001), compared to the Mx-arm. After two rounds, specificity improved for both modalities (87.1% for MRI; 93.0% for Mx; p<0.001) and no ≥T2 tumors or interval cancers occurred in the MRI-arm. All tumors ≥T2 were in the two highest density categories. MRI detected more small invasive tumors than Mx across all density categories.

Conclusions: In real-life practice the MRI-arm detected more, relevantly smaller, and far more often node negative tumors, and also at low density in women with a familial risk for breast cancer.

Table 1Characteristics of participating women at baseline and of the detected breast cancers, according to study armParticipantsMRI-arm n=675Mx-arm n=680MRI-arm vs. Mx-arm p-valueMean age yr ± SD44.6 ± 6.244.7 ± 6.3 Premenopausal512 (76%)505 (74%) Previous Mx ≤ 2 yr536 (79 %)542 (80%) Previous Mx > 2 years ago23 ( 3%)29 ( 4%) Previous MRI ≤ 2 years ago62 ( 9%)81 (12%) Previous MRI > 2 years ago91 (14%)89 (13%) BI-RADS density category*   I (entirely fat)88 (13%)92 (14%) II (scattered densities)248 (37%)229 (34%) III (heterogeneously dense)238 (35%)243 (36%) IV (extremely dense)98 (15%)102 (15%) Mean age at cancer detection49,6 ± 7.049,8 ± 4,70.74No cancer – no. (%)634 (94%)666 (98%) Invasive breast cancers – no. (%)25 (4%)7 (1%)<0.001 (noBC/inv BC/DCIS)DCIS – no. (%)16 (2%)7 (1%) Median size of invasive cancers8 mm17 mm0.006T1a/b15 (60%)1 (14%) T1c7 (28%)4 (57%)0.078 (T1a-b/T1c/≥ T2)≥ T23 (12%)2 (29%) Node pos5 (20%)5 (71%)0.019 (N+/-)Node negative20 (80%)2 (29%) DCIS grade 15 (31%)2 (29%) DCIS grade 28 (50%)4 (57%)1 (dcis gr1,2,3)DCIS grade 33 (19%)1 (14%) *Determined by radiologists, according to the fourth ACR BI-RADS edition

Citation Format: Tilanus-Linthorst MM, Saadatmand S, Geuzinge AH, Rutgers EJ, Mann R, de Roy van Zuidewijn DB, Zonderland HM, Tollenaar RA, Lobbes MB, Ausems MG, van 't Riet M, Hooning MJ, Mares-Engelbert I, Luiten EJ, Heijnsdijk EA, Verhoef C, Karssemeijer N, Oosterwijk JC, Obdeijn I-M, de Koning HJ. MRI breast cancer screening compared to mammography in women with a familial risk: A multicenter randomized controlled trial [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-13-01.

Benefits of preoperative MRI in breast cancer surgery studied in a large population-based cancer registry

Background

Although evidence for the benefits of preoperative MRI in breast cancer is lacking, use of MRI is increasing and characterized by large interhospital variation. The aim of the study was to evaluate MRI use and surgical outcomes retrospectively.

Methods

Women with invasive breast cancer (pT1–3) or ductal carcinoma in situ (DCIS), diagnosed in 2011–2013, were selected from the Netherlands Cancer Registry and subdivided into the following groups: invasive cancer, high-grade DCIS, non-palpable cancer, age 40 years or less, and invasive lobular cancer. Associations between preoperative MRI use and initial mastectomy, resection margin after breast-conserving surgery (BCS), re-excision after BCS, and final mastectomy were analysed.

Results

In total, 5514 women were included in the study; 1637 (34·1 per cent) of 4801 women with invasive cancer and 150 (21·0 per cent) of 713 with DCIS had preoperative MRI. Positive resection margins were found in 18·1 per cent women who had MRI and in 15·1 per cent of those who did not (adjusted odds ratio (OR) 1·20, 95 per cent c.i. 1·00 to 1·45), with no differences in subgroups. Re-excision rates were 9·8 per cent in the MRI group and 7·2 per cent in the no-MRI group (adjusted OR 1·33, 1·04 to 1·70), with no differences in subgroups. In the MRI group, 38·8 per cent of patients ultimately underwent mastectomy, compared with 24·2 per cent in the no-MRI group (adjusted OR 2·13, 1·87 to 2·41). This difference was not found for patients aged 40 years or less, or for those diagnosed with lobular cancer.

Conclusion

No subgroup was identified in which preoperative MRI influenced the risk of margin involvement or re-excision rate after BCS. MRI was significantly associated with more extensive surgery, except in patients aged 40 years or less and those with invasive lobular cancer. These results suggest that use of preoperative MRI should be more targeted, and that general, widespread use be discouraged.

Abstract P5-05-05: Lower mitotic activity in BRCA1/2-associated primary breast cancers occurring after risk-reducing salpingo-oophorectomy

Background Bilateral salpingo-oophorectomy reduces breast cancer (BC) risk by about 50% in BRCA1/2 mutation carriers when performed premenopausally. It has been hypothesized that growth activity of BCs originating after risk-reducing salpingo-oophorectomy (RRSO) is lower. We compared tumor characteristics and growth rates of BRCA1/2-associated primary BCs (PBCs) detected after RRSO with those of tumors originating without RRSO.

Methods From a cohort of 271 female BRCA1/2-associated patients with screen detected BC, 20 BRCA1/2 mutation carriers with PBC detected ≥12 months after RRSO were selected (RRSO group). Controls were 36 BRCA1/2 mutation carriers with PBC detected without RRSO (non-RRSO group) matched for age at PBC diagnosis (± 2.5 years) and for BRCA1 or BRCA2 mutation (intended matching ratio 1:2). Tumor growth rates, expressed as tumor volume doubling times (DT), were calculated. Pathology samples were revised for histological subtype, tumor differentiation grade, estrogen receptor (ER), progesterone receptor (PR) and HER2 status. Imaging examinations (magnetic resonance imaging (MRI), mammography) before and at BC diagnosis were revised.

Results Median age at PBC diagnosis was 52 years (range 35-67). MRI detected more BC than mammography in the RRSO-group as compared to the non-RRSO group (83% vs. 39%, P = 0.02). Tumor size at diagnosis was smaller in the RRSO group (11.0 mm vs. 17.0 mm, P = 0.01). Mitotic activity indexes (MAI) in the RRSO and non-RRSO group were 12 vs. 22 mitotic counts/2 mm2 (P = 0.02). No significant differences in differentiation grade, ER and HER2 status were found. PR-status was more often positive in the RRSO group without reaching statistical significance (38% vs. 13%, P = 0.07). Median DT in the RRSO group was 124 days (range 89-193) and 93 days (range 54-253) in the non-RRSO group (P = 0.47).

Conclusion BC occurring after RRSO in BRCA mutation carriers features a lower MAI, suggesting a less aggressive biological behavior. When confirmed in larger series, this may have consequences for BC screening protocols for BRCA1/2 mutation carriers after RRSO.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-05-05.

Abstract P3-02-09: Cost-effectiveness of screening with additional MRI for women with familial risk for breast cancer without a genetic predisposition

Background: To reduce mortality risk, women with a family history of breast cancer are often screened with mammography before 50 years of age. Additional Magnetic Resonance Imaging (MRI) can improve sensitivity. MRI screening is cost-effective for BRCA1/2 mutation carriers. However, for women with a family history of breast cancer without a proven mutation cost-effectiveness is not clear. We evaluated the cost-effectiveness of additional MRI for women with a familial risk in the largest prospective MRI screening study: the Dutch MRI Screening Study (MRISC).

Materials & Methods: Between 1999 and 2007 a total of 1597 women (8370 women years at risk) between 25–70 years, with an estimated cumulative lifetime risk of 15–50% for breast cancer participated in the MRISC. Women were screened with clinical breast examination (CBE) every six months and annual mammography and MRI. We calculated the costs per detected breast cancer. In addition, MRISC data were incorporated into a micro simulation screening analysis model: MISCAN. This model simulates screening programs with different screening modalities and time intervals. Different screening schemes were evaluated and the cost per life-year gained (CLYG) estimated.

Results: Forty-seven breast cancers, including 9 Ductal Carcinoma in Situ, were detected. Screening with additional MRI leads to a cost per detected breast cancer treated of €101,962. In increasing age-cohorts the cost decreased, probably due to the higher breast cancer incidence. The cost per detected and treated breast cancer in age group 40–50 years doubled in the age group >60 years. We will demonstrate these results more extensively.

With MISCAN modeling we predicted that screening with this scheme from age 35 to 60 years reduces breast cancer mortality by 30% at a CLYG of €119,945 (3.5% discounting), compared to 21% estimated mortality reduction at €45,707 CLYG with mammography and CBE alone.

Conclusion: Screening with MRI may improve survival for women with familial risk for breast cancer, but is expensive. However, it may be cost-effective for a select group. We will discuss subgroups that may benefit from MRI screening and in which age category MRI was most effective in our study.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-02-09.

Breast tumor characteristics of BRCA1 and BRCA2 gene mutation carriers on MRI

The appearance of malignant lesions in BRCA1 and BRCA2 mutation carriers (BRCA-MCs) on mammography and magnetic resonance imaging (MRI) was evaluated. Thus, 29 BRCA-MCs with breast cancer were retrospectively evaluated and the results compared with an age, tumor size and tumor type matched control group of 29 sporadic breast cancer cases. Detection rates on both modalities were evaluated. Tumors were analyzed on morphology, density (mammography), enhancement pattern and kinetics (MRI). Overall detection was significantly better with MRI than with mammography (55/58 vs 44/57, P = 0.021). On mammography, lesions in the BRCA-MC group were significantly more described as rounded (12//19 vs 3/13, P = 0.036) and with sharp margins (9/19 vs 1/13, P = 0.024). On MRI lesions in the BRCA-MC group were significantly more described as rounded (16/27 vs 7/28, P = 0.010), with sharp margins (20/27 vs 7/28, P < 0.001) and with rim enhancement (7/27 vs 1/28, P = 0.025). No significant difference was found for enhancement kinetics (P = 0.667). Malignant lesions in BRCA-MC frequently have morphological characteristics commonly seen in benign lesions, like a rounded shape or sharp margins. This applies for both mammography and MRI. However the possibility of MRI to evaluate the enhancement pattern and kinetics enables the detection of characteristics suggestive for a malignancy.

Tumor characteristics and detection method in the MRISC screening program for the early detection of hereditary breast cancer

In the MRISC study, women with an inherited risk for breast cancer were screened by a 6-month clinical breast examination (CBE) and yearly MRI and mammography. We found that the MRISC screening scheme could facilitate early breast cancer diagnosis and that MRI was a more sensitive screening method than mammography, but less specific. In the current study we investigated the contribution of MRI in the early detection of breast cancer in relation to tumor characteristics. From November 1999 to October 2003, 1909 women were included and 50 breast cancers were detected, of which 45 were evaluable and included in the current study. We compared the characteristics of tumors detected by MRI-only with those of all other (non-palpable) screen-detected tumors. Further, we compared the sensitivity of mammography and MRI within subgroups according to different tumor characteristics. Twenty-two (49%) of the 45 breast cancers were detected by MRI and not visible at mammography, of which 20 (44%) were also not palpable (MRI-only detected tumors). MRI-only detected tumors were more often node-negative than other screen-detected cancers (94 vs. 59%; P=0.02) and tended to be more often <or=1 cm (58 vs. 31%; P=0.11). MRI was more sensitive than mammography for a wide spectrum of invasive tumor characteristics i.e., size, nodal status, histology, grade and ER status. Half of the breast cancers detected in this study were visible by MRI only and these tumors were smaller and significantly more often node-negative than other screen-detected tumors, suggesting that MRI makes an important contribution to the early detection of hereditary breast cancer.

Effectiveness of breast cancer surveillance in BRCA1/2 gene mutation carriers and women with high familial risk

PURPOSE

Women with a high breast cancer risk due to a familial predisposition may choose between preventive surgery and regular surveillance. The effectiveness of surveillance in high-risk women and especially BRCA1/2 mutation carriers is unknown. We present first results from a single large family cancer clinic.

PATIENTS AND METHODS

Women with breast cancer risk over 15% were examined by physical examination every 6 months and mammography every year. Detection rates and screening parameters were calculated for the total group and separately for different age and genetic risk groups.

RESULTS

At least one examination was performed in 1,198 women: 449 moderate and 621 high-risk women and 128 BRCA1/2 mutation carriers. Within a median follow-up of 3 years, 35 breast cancers were detected (four ductal carcinoma-in-situ; 31 invasive tumors); the average detection rate was 9.7 per 1,000. Detection rates (95% confidence interval) for moderate and high-risk women and BRCA1/2 carriers were 3.3 (1.1 to 8.6), 8.4 (5.4 to 13.2), and 33 (17 to 63) per 1,000 person-years, respectively. The ratio of observed cases versus breast cancers expected in an average-risk population of comparable age was 2.7, 7.0 and 23.7 respectively. Overall, node negativity was 65%; 34% of primary tumors were less than 10 mm; sensitivity was 74%. Results with respect to tumor stage and sensitivity were less favorable in BRCA1/2 carriers and in women under the age of 40.

CONCLUSION

It is possible to identify young women at high risk for breast cancer. The number of cancers detected was significantly greater than expected in an age-matched average-risk population and related to the risk category. Overall, screening parameters were comparable to population screening data, with less favorable results in the youngest age group (< 40) and BRCA1/2 carriers.

First experiences in screening women at high risk for breast cancer with MR imaging

Women with a genetic predisposition for breast cancer are often advised surveillance with physical examination twice a year and mammography once a year from 25 years onwards. However, the sensitivity of the mammography decreases when breast tissue is dense and this is seen in 40-50% of women under 50 years. We therefore investigated whether magnetic resonance imaging (MRI) in addition to the normal surveillance could detect cancers otherwise missed. In 109 women with over 25% risk of breast cancer, MRI was performed because over 50% dense breast tissue was seen at mammography and no suspect lesion was seen at the previous screening. MRI detected breast cancers in three patients (2.8%) occult at mammography and with no new palpable tumor, twice at stage T1bN0 and T1cN0 once. Two cancers were expected. MRI was false positive in six women, resulting in two benign local excisions because ultrasound or fine needle examination confirmed suspicion. We had no false negative MRI results. MRI proved true benign in four BRCA 1/2 gene mutation carriers at histologic examination. Preoperative wire localization of the malignancies detected at MRI proved necessary as the tumor was not palpable in the lumpectomy specimen nor visible at specimen radiology. The extra cost of breast MRI in addition to mammography and physical examination was [symbol: see text]uro13.930 per detected cancer. The cost of the detection of one breast cancer patient in our national screening program is [symbol: see text]uro9000. During follow-up of patients with a familial risk in whom the first breast cancer was detected at MRI, MRI detected two recurrent cancers in stage T1bN0 and T1cN0 and one contralateral cancer T1aNo. Breast MRI is promising in screening young women at high risk for breast cancer, as it can advance the detection of cancers still occult at mammography and physical examination; but the cost may be considerable.

MR imaging-guided sonography followed by fine-needle aspiration cytology in occult carcinoma of the breast

OBJECTIVE

In patients with axillary metastases as clinical evidence of possible occult breast cancer, a combined approach of MR imaging, sonography, and aspiration biopsy cytology was evaluated.

SUBJECTS AND METHODS

Thirty-one women with metastatic adenocarcinoma in their axillary lymph nodes originating from an unknown primary site underwent MR imaging of the breast because physical examination and mammography findings were normal. Twenty of the 31 women had no history of malignancy, 10 had been previously treated for contralateral breast cancer, and one patient had nodal metastases in the contralateral axilla at the time breast cancer was detected. When a contrast-enhancing lesion was revealed on MR imaging of the breast, sonography and fine-needle aspiration cytology were also performed.

RESULTS

MR imaging revealed the primary breast cancer in eight (40%) of the 20 patients without a history of malignancy. MR imaging of the breast revealed a second primary cancer in three (27%) of the 11 patients with previous or simultaneous breast cancer. All lesions were identified with sonography and verified by cytology and histology.

CONCLUSION

In women with axillary lymph node metastases from adenocarcinoma, MR imaging of the breast should be added to clinical examination and mammography before defining the breast cancer as occult. The combined approach of MR imaging, sonography, and aspiration fine-needle cytology is a good alternative to the MR imaging-guided biopsy.

MR lesion detection in a breast cancer population

Implementation of MR imaging of the breast as an extension of the existing imaging modalities in the diagnosis of breast cancer was evaluated in a university cancer center, MR imaging of the breast was performed in 54 patients, in whom the MR results were compared with the triple test (the combination of clinical examination, mammographic evaluation, and cytology) and the final histological diagnosis. MR imaging of the breast depicted 30 of the 33 malignancies (sensitivity, 91%). In two of the malignancies, the carcinoma was clinically and mammographically occult. For the three patients with a false-negative MRI diagnosis, the conventional mammography showed suspicions clustered microcalcifications as a sign of in situ carcinoma. For seven patients, MR imaging of the breast incorrectly suggested the presence of a malignant lesion (specificity, 67%). To improve MR specificity, we perform MR-guided ultrasonographic fine-needle aspiration biopsy (FNAB). Although MR imaging of the breast is a highly sensitive examination, conventional x-ray mammography remains the most efficient imaging modality in the diagnosis of breast cancer. In our patient population, MR imaging of the breast had additional value for women with mammographically dense breast tissue and especially for patients with clinical evidence of breast carcinoma that could not be detected with conventional diagnostic methods.