Functional variants at the 11q13 risk locus for breast cancer regulate cyclin D1 expression through long-range enhancers

Analysis of 4,405 variants in 89,050 European subjects from 41 case-control studies identified three independent association signals for estrogen-receptor-positive tumors at 11q13. The strongest signal maps to a transcriptional enhancer element in which the G allele of the best candidate causative variant rs554219 increases risk of breast cancer, reduces both binding of ELK4 transcription factor and luciferase activity in reporter assays, and may be associated with low cyclin D1 protein levels in tumors. Another candidate variant, rs78540526, lies in the same enhancer element. Risk association signal 2, rs75915166, creates a GATA3 binding site within a silencer element. Chromatin conformation studies demonstrate that these enhancer and silencer elements interact with each other and with their likely target gene, CCND1.

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.

P4-11-04: Risk of Primary (PBC) and Contralateral Breast Cancer (CBC) after Ovarian Cancer (OC) in BRCA1 and BRCA2 Mutation Carriers; Implications for Surveillance and Risk Reducing Mastectomy

Background In view of the increased risk of developing breast (BC) cancer, BRCA mutation carriers are offered intensive surveillance or risk reducing mastectomy (RRM) and/or salpingo-ovariectomy (RRSO). It is insufficiently clear how to counsel mutation carriers who have been treated for OC, and it may be questioned whether RRM is indicated. It is possible that BC risk, both of primary (PBC) and contralateral BC (CBC), may be modified by the treatment given for OC mostly including surgery and platinum-based chemotherapy. Further, the BC risk has to be weighted against the risk of death after OC. So far, there are no data available on the PBC or CBC risk after OC in BRCA mutation carriers.

Patients and Methods From the database of the institutional Family Cancer Clinic (FCC), we selected BRCA-associated OC patients either without (n= 79, at risk of PBC) or with a history of unilateral BC (n=37, at risk of CBC). Controls were BRCA mutation carriers without OC, either without (n=351) or with a history of unilateral BC (n=294). Follow-up started at OC diagnosis, and for controls at date of first visit at the FCC or the 35th birthday. Exclusion criteria were: other malignancy besides epithelial OC or BC, inadequate follow-up data, bilateral breast cancer or mastectomy. Data analyses were performed using t- and chi-squared tests, and Kaplan-Meier survival method with death prior to BC as competing risk event.

Results Only six OC patients (5.1%) did not receive chemotherapy as part of primary therapy for OC, five at risk of PBC and one at risk of CBC. Chemotherapy schedules were mainly platinum-based (92%). RRSO was performed in 45% of the controls.

The risks of PBC at 2, 5, and 10 years in BRCA-associated OC patients were 3%, 6% and 11%, respectively, versus 6%, 16% and 28% in unaffected BRCA mutation carriers (p=0.03). The mortality rate at those time points in the OC group was 13%, 33% and 61%, respectively, versus 1%, 2% and 2% in unaffected mutation carriers (p<0.001).

In patients with a history of unilateral BC, the risks of CBC at 2, 5, and 10 years in OC patients were 0%, 7% and 7%, respectively, versus 6%, 16% and 34% in the BC patients without OC (p=0.06). The mortality rate at similar time points was 19%, 34%, and 55%, respectively, in the OC group versus 4%, 11%, and 21% for the non-OC patients (p<0.001).

Conclusions The risk of developing a PBC or CBC was much lower in BRCA mutation carriers with a history of OC than in mutation carriers without OC. Also, since the 10-year mortality rate after ovarian cancer was 55–60% and the risk of developing a PBC or CBC at the highest was 11% over the same time period, our data suggest that intensive breast cancer surveillance strategies for the BRCA-associated ovarian cancer group might be reconsidered, while risk reducing mastectomy is not indicated unless in specific cases requiring careful consideration in a multisciplinary setting. Further studies in larger groups are warranted.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-11-04.

Sensitivity to Taxane Chemotherapy for Metastatic Breast Cancer in BRCA1 and BRCA2 Mutation Carriers Compared to Sporadic Breast Cancer Patients

Purpose: Data of in vitro and small retrospective studies suggest that breast cancer (BC) (cells) without functional BRCA1 or BRCA2 protein have an increased sensitivity to chemotherapeutic agents causing double strand DNA breaks, while sensitivity to spindle poisons, such as paclitaxel and docetaxel, has been found to be decreased. Clinical data on the latter, however, are very scarce. In this study, we assessed the sensitivity to taxane chemotherapy for metastatic BRCA1/2-associated compared with sporadic breast cancer.Methods: From the family cancer clinic database, we retrieved 36 BRCA1 and 13 BRCA2-associated BC patients treated with taxane chemotherapy for metastatic disease before October 1, 2008, and with available data on follow-up and response assessment. Objective response (OR), and progression-free survival (PFS) after start of taxane chemotherapy were compared with those of 62 sporadic patients with comparable age at diagnosis and year of detection of metastatic BC. A t-test or chi-square test was used to test for differences in characteristics and response types, and Kaplan-Meier survival analysis to calculate PFS.Results: Taxane chemotherapy consisted of docetaxel (n= 76) or paclitaxel (n=21), while 10 (9%) patients received a taxane/trastuzumab regimen. It was given as first-line palliative therapy in 9 BRCA1, 1 BRCA2 and 22 sporadic patients; but mainly as second/third line treatment (BRCA1 n=27, BRCA2 n=12, sporadic patients n=40, respectively). As compared to sporadic patients, BRCA1-associated patients had a significantly lower OR rate (ORR) overall (22% vs 46%, p<0.001) and to 2nd/3rd line taxane treatment (19% vs 46%, p<0.001). Median PFS was shorter in BRCA1 patients (2.0 vs 4.1 mo, p=0.08), with a trend for significance for 2nd/3rd line therapy (1.6 vs 3.9 mo, p=0.05). Also, compared to BRCA2 patients, the ORR in BRCA1 patients was significantly lower, overall as well as to 2nd/3d line therapy (both p=0.003). In BRCA2 mutation carriers compared to sporadic patients, the ORR was higher (75% vs 48%, p=0.28) and PFS longer (6.4 vs 4.1 mo, p=0.33). After exclusion of the patients receiving a taxane/trastuzumab schedule, similar data were observed.Conclusion: Objective response rate to taxane chemotherapy for metastatic disease is lower in BRCA1-associated BC in comparison with sporadic as well as BRCA2-associated BC, resulting in a shorter PFS. If confirmed, these data may have substantial clinical relevance.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2098.

Contralateral Breast Cancer in BRCA1/2 Mutation Carriers: Risk Assessment by Age at Diagnosis of the First Primary Breast Cancer

Purpose Age at diagnosis of the first breast cancer is a known predictive factor of the risk of contralateral breast cancer (CBC) in BRCA1/2 mutation carriers. However, accurate risk estimates for different age subgroups are scarce.Methods We studied the risk of CBC in 560 women with a primary breast cancer (PBC) from families with a proven BRCA1 or BRCA2 mutation in relation to the age at diagnosis of the first PBC, taking into account history of oophorectomy. Time at risk was the period between diagnosis of the first PBC and date of contralateral breast cancer, contralateral mastectomy, metastatic disease, death or last follow-up. Oophorectomy was treated as a time-dependent covariate. Patients with bilateral breast cancer diagnosed before the first visit at the family cancer clinic were excluded.Results We observed 96 CBCs in 423 BRCA1 mutation carriers and 21 cases in 137 BRCA2 mutation carriers. Actuarial risk of CBC at 5, 10 and 15 years was 14%, 34% and 39%, respectively, for BRCA1-, and 13%, 22% and 27%, respectively, for BRCA2 mutation carriers. For BRCA1 carriers 10-year actuarial risk of CBC was 54% for women with a PBC ≤ 30 years, 39% for the group with PBC between 31-40 years, 26% for the 41-50 group and 17% for those with PBC > 50 years. In BRCA2 carriers 10-year risk of CBC was 28% for women with a PBC ≤ 40 years, 19% for the 41-50 group and 10% for those with PBC > 50 years. For BRCA1 carriers who had an oophorectomy, 10-year risk of CBC was 33% and 26%, respectively, for those with PBC younger and older than 40 years, against 44% and 24% in women who had no such treatment. In BRCA2 carriers with a history of oophorectomy 10-year risk of CBC was 21% and 14%, respectively, for those with PBC younger and older than 40 years, while the risk was 29% and 17%, respectively, in women without oophorectomy. Effect of adjuvant therapy is being analyzed and will be presented at the meeting.Conclusions The availability of risk estimates of CBC by more detailed age groups at PBC is a helpful tool in the counselling process concerning screening and/or preventive surgery for breast cancer patients with a BRCA1 or BRCA2 mutation.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 903.