Kaplan-Meier analysis was adjusted for year of diagnosis and study.
Bolton KL, Chenevix- Trench G, Goh C, Sadetzki S, Ramus SJ, Karlan BY, Lambrechts D, Despierre E, Barrowdale D, McGuffog L, Healey S, Easton DF, Sinilnikova O, Benítez J, García MJ, Neuhausen S, Gail MH, Hartge P, Peock S, Frost D, Evans DG, Eeles R, Godwin AK, Daly MB, Kwong A, Ma ESK, Lázaro C, Blanco I, Montagna M, D'Andrea E, Nicoletto MO, Johnatty SE, Kjær SK, Jensen A, Høgdall E, Goode EL, Fridley BL, Loud JT, Greene MH, Mai PL, Chetrit A, Lubin F, Hirsh-Yechezkel G, Glendon G, Andrulis IL, Toland AE, Senter L, Gore ME, Gourley C, Michie CO, Song H, Tyrer J, Whittemore AS, McGuire V, Sieh W, Kristoffersson U, Olsson H, Borg Å, Levine DA, Steele L, Beattie MS, Chan S, Nussbaum RL, Moysich KB, Gross J, Cass I, Walsh C, Li AJ, Leuchter R, Gordon O, Garcia-Closas M, Gayther SA, Chanock SJ, Antoniou AC, Pharoah PDP, EMBRACE, kConFab Investigators, and The Cancer Genome Atlas Research Network FT. Association Between BRCA1 and BRCA2 Mutations and Survival in Women With Invasive Epithelial Ovarian Cancer. JAMA. 2012;307(4):382-389. doi:10.1001/jama.2012.20
Author Affiliations: Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland (Drs Bolton, Gail, Chanock, and Hartge); David Geffen School of Medicine, University of California, Los Angeles (Dr Bolton); Queensland Institute of Medical Research, Royal Brisbane Hospital, Herston, Australia (Drs Chenevix-Trench and Johnatty and Ms Healey); Addenbrooke's Hospital, Cambridge, England (Ms Goh); Gertner Institute for Epidemiology and Health Policy Research, Sheba Medical Center, Tel Hashomer, Israel (Drs Sadetzki and Hirsh-Yechezkel and Mss Chetrit and Lubin); Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel (Dr Sadetzki); Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles (Drs Ramus and Gayther); Women's Cancer Program, Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, California (Drs Karlan, Cass, Walsh, Li, Leuchter, and Gordon and Ms Gross); VIB Vesalius Research Center, University of Leuven, Leuven, Belgium (Dr Lambrechts); Department of Obstetrics and Gynaecology, University Hospitals Leuven, University of Leuven, Leuven, Belgium (Dr Despierre); Center for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge, England (Drs Easton, Peock, and Antoniou and Mr Barrowdale and Mss McGuffog and Frost); Unit of Genetic Predisposition to Common Cancers, Hospices Civils de Lyon−Center Léon Bérard, Lyon, and INSERM U1052, CNRS UMR5286, University Lyon 1, Cancer Research Center of Lyon, Lyon, France (Dr Sinilnikova); Human Genetics Group (Dr García), Human Cancer Genetics Program and Genotyping Unit, Spanish National Cancer Research Center (Dr Benítez), and CIBERER (Drs Benítez and García), Madrid, Spain; Department of Population Sciences, Beckman Research Institute of the City of Hope, Duarte, California (Dr Neuhausen and Ms Steele); Genetic Medicine, Manchester Academic Health Sciences Center, Central Manchester University Hospitals NHS Foundation Trust, Manchester, England (Dr Evans); Oncogenetics Team, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom (Dr Eeles); Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City (Dr Godwin); Department of Clinical Genetics, Fox Chase Cancer Center, Philadelphia, Pennsylvania (Dr Daly); The Hong Kong Hereditary Breast Cancer Family Registry, Cancer Genetics Center (Drs Kwong and Ma), and Division of Molecular Pathology (Dr Ma), Hong Kong Sanatorium and Hospital, Central Block, Hong Kong; Division of Breast Surgery, University of Hong Kong, Queen Mary Hospital, Hong Kong (Dr Kwong); Hereditary Cancer Program, Catalan Institute of Oncology, L’Hospitalet, Barcelona, Spain (Drs Lázaro and Blanco); Immunology and Molecular Oncology Unit (Dr Montagna) and Medical Oncology Unit 1 (Dr Nicoletto), Istituto Oncologico Veneto IRCCS, Padua, Italy; Department of Oncology and Surgical Sciences, Istituto Oncologico Veneto IOV - IRCCS, Padua, Italy (Dr D’Andrea); Department of Virus, Hormones, and Cancer, Danish Cancer Society, and Department of Gynecology, Rigshospitalet, University of Copenhagen (Drs Kjær, Jensen, and Høgdall), Copenhagen, Denmark; Department of Health Sciences Research, Mayo Clinic College of Medicine, Rochester, Minnesota (Drs Goode and Fridley); Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland (Drs Loud, Greene, and Mai); Ontario Cancer Genetics Network, Cancer Care Ontario (Dr Andrulis and Mr Glendon), and Samuel Lunenfeld Research Institute, Mount Sinai Hospital (Dr Andrulis), Toronto, Ontario, Canada; Departments of Internal Medicine and Molecular Virology, Immunology, and Medical Genetics, The Comprehensive Cancer Center, Ohio State University, Columbus (Dr Toland); Clinical Cancer Genetics Program, Department of Internal Medicine, The Comprehensive Cancer Center, Ohio State University, Columbus (Ms Senter); Gynecological Oncology Unit, The Royal Marsden Hospital, London, England (Dr Gore); University of Edinburgh Cancer Research Center, Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, Scotland (Drs Gourley and Michie); Cancer Research United Kingdom, Departments of Oncology and Public Health and Primary Care, University of Cambridge, Strangeway's Research Laboratory, Cambridge, England (Drs Song, Tyrer, and Pharoah); Department of Health Research and Policy, Stanford University School of Medicine, Stanford, California (Drs Whittemore, McGuire, and Sieh); Department of Clinical Genetics, University and Regional Laboratories Skåne and Lund University, Lund, Sweden (Dr Kristoffersson); Department of Oncology, Lund University, Lund, Sweden (Drs Olsson and Borg); Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (Dr Levine); University of California San Francisco Cancer Risk Program, San Francisco (Drs Beattie and Nussbaum and Ms Chan); Department of Medicine, University of California, San Francisco (Drs Beattie and Nussbaum); Department of Cancer Prevention and Control, Roswell Park Cancer Institute, Buffalo, New York (Dr Moysich); and Sections of Epidemiology and Genetics, Institute of Cancer Research and Breakthrough Breast Cancer Research Center, London, England (Dr Garcia-Closas).
Context Approximately 10% of women with invasive epithelial ovarian cancer (EOC) carry deleterious germline mutations in BRCA1 or BRCA2. A recent article suggested that BRCA2 -related EOC was associated with an improved prognosis, but the effect of BRCA1 remains unclear.
Objective To characterize the survival of BRCA carriers with EOC compared with noncarriers and to determine whether BRCA1 and BRCA2 carriers show similar survival patterns.
Design, Setting, and Participants A pooled analysis of 26 observational studies on the survival of women with ovarian cancer, which included data from 1213 EOC cases with pathogenic germline mutations in BRCA1 (n = 909) or BRCA2 (n = 304) and from 2666 noncarriers recruited and followed up at variable times between 1987 and 2010 (the median year of diagnosis was 1998).
Main Outcome Measure Five-year overall mortality.
Results The 5-year overall survival was 36% (95% CI, 34%-38%) for noncarriers, 44% (95% CI, 40%-48%) for BRCA1 carriers, and 52% (95% CI, 46%-58%) for BRCA2 carriers. After adjusting for study and year of diagnosis, BRCA1 and BRCA2 mutation carriers showed a more favorable survival than noncarriers (for BRCA1: hazard ratio [HR], 0.78; 95% CI, 0.68-0.89; P < .001; and for BRCA2: HR, 0.61; 95% CI, 0.50-0.76; P < .001). These survival differences remained after additional adjustment for stage, grade, histology, and age at diagnosis (for BRCA1: HR, 0.73; 95% CI, 0.64-0.84; P < .001; and for BRCA2: HR, 0.49; 95% CI, 0.39-0.61; P < .001). The BRCA1 HR estimate was significantly different from the HR estimated in the adjusted model (P for heterogeneity = .003).
Conclusion Among patients with invasive EOC, having a germline mutation in BRCA1 or BRCA2 was associated with improved 5-year overall survival. BRCA2 carriers had the best prognosis.
Germline mutations in the tumor suppressor genes BRCA1 (NCBIEntrezGene672) and BRCA2 (NCBIEntrezGene 675) are the strongest known genetic risk factors for both breast and epithelial ovarian cancer (EOC) and are found in 6% to 15% of women with EOC.1- 3BRCA1 is involved in DNA repair, cell-cycle checkpoint control, chromatin remodeling, transcriptional regulation, and mitosis, and BRCA2 has an important role in homologous recombination.4 The clinical characteristics of EOCs among BRCA1/2 carriers differ from that of noncarriers. BRCA1 -related disease is more likely to be of serous histology,5 high grade,6 and advanced stage.3 Less data are available for BRCA2 -related EOC due to their lower prevalence and lower EOC penetrance relative to BRCA1, but a similar pattern is generally reported.5,7
The relative prognosis of BRCA1/2 carriers and noncarriers is unclear. A recent article8 found a more favorable outcome for BRCA2 mutation carriers, with no significant difference in outcome for BRCA1 mutation carriers compared with noncarriers. However, some studies have demonstrated a more favorable prognosis for BRCA1 and BRCA2 carriers6,7,9 compared with noncarriers, whereas other studies have reported no significant difference.10,11 Several factors may account for these divergent results. Most studies contained less than 50 carriers and all contained less than 250 carriers, resulting in imprecise survival estimates. Small sample sizes have also resulted in the grouping of BRCA1 and BRCA2 carriers together for analysis, despite potential prognostic differences. In addition, adjustment for prognostic factors known to differ by carrier status has varied among studies. In addition, few studies used appropriate statistical methods to account for the potential bias resulting from the inclusion of prevalent cases.12 The mechanism driving the association between BRCA1/2 mutations and survival is not known but some retrospective studies suggested that the survival advantage of carriers could be mediated through improved response to platinum-based agents.7,13 This is consistent with in vitro studies showing that BRCA1 and BRCA2 deficient cells are hypersensitive to drugs, which induce double-strand DNA breaks such as platinum-based agents.14
The goal of our study was to collate the data from multiple EOC case series with data on BRCA1 and BRCA2 mutation status to provide definitive evidence of the relative effect of germline BRCA1 and BRCA2 mutations on prognosis. The results could provide insight into the biology of BRCA1/2 mutations, improve clinical management of mutation carriers, and have implications for clinical trial design, particularly for agents targeting BRCA1/2 dysfunction, such as poly (ADP-ribose) polymerase inhibitors.15
Study participants were women with confirmed invasive EOC, both with and without pathogenic mutations in BRCA1 and BRCA2. Participants were drawn from 26 studies (10 from the United States, 6 from Europe, 2 from Israel, 1 from Hong Kong, 1 from Canada, 1 from Australia, and 5 from the United Kingdom). Participants were recruited and enrolled in clinical research protocols between 1987 and 2010 that were approved by local institutional review boards. Written consent was obtained from all living patients. Most participating studies were affiliated with either the Consortium of Investigators of Modifiers of BRCA1/216 or the Ovarian Cancer Association Consortium.17
Investigators submitted data on patient demographics, tumor pathology, vital status, and treatment to the coordinating group in Cambridge, England. In some studies, EOC cases were recruited based on a strong family history of ovarian, breast cancer (family-based), or both, while other cases used population-based sampling or enrolled a consecutive series of cases treated at a single or multiple institutions. In all studies, BRCA1/2 carriers and noncarriers were enrolled into the study using the same criteria.
Mutations were considered pathogenic if they met criteria defined by the Breast Cancer Information Core18,19 and were grouped into categories based on their predicted functional effect.20- 23 Women with variants of unknown significance in BRCA1 or BRCA2 were excluded. Class I mutations are the most frequent and represent loss-of-function mutations predicted to result in reduced transcript or protein level due to mRNA nonsense-mediated RNA decay, translational retention, or absence of expression. Class II contains those mutations likely to generate stable proteins that may have some normal or dominant negative function. This includes missense substitutions and mutations generating a premature stop codon in the last exon.
All participants were screened for both BRCA1 and BRCA2 mutations with 3 exceptions. In 3 family-based studies, the Kathleen Cuningham Consortium for Research into Familial Breast Cancer, the UK Gilda Radner Familial Ovarian Cancer Registries, and the National Cancer Institute study, some EOC cases were not tested for BRCA1/2 and BRCA1/2 status was assumed to be the same as that of affected family members who had been tested. The noncarrier group from the Royal Marsden Hospital study contained some untested EOC cases but who reported no family history of breast or ovarian cancer and were therefore considered unlikely to harbor mutations. In addition, in the Stanford Genetic Epidemiology of Ovarian Cancer study, only BRCA1 mutation testing was performed. A variety of methods were used to perform mutation testing (eTable 1).
Data on tumor pathology, vital status, and treatment were obtained through a combination of medical records, local cancer registries, and death certificates. Infrequently, vital status was determined through direct contact with a physician or family member of the patient. In a subset of studies, information regarding residual disease following primary surgery was available from medical records. Optimal debulking was defined as residual disease of 1 cm or less and suboptimal debulking as residual disease of more than 1 cm.
BRCA1/2 status may modify response to platinum-based chemotherapy, which became standard of care in most countries around 1990. Among the 36% of patients with chemotherapy data, 95% of cases diagnosed after 1990 were reported to have received a platinum-based agent. We therefore excluded women diagnosed before 1990 if chemotherapy regime was unknown, and those known not to have received platinum-based chemotherapy.
The primary end point was overall survival up to 5 years following EOC diagnosis. We chose this end point to minimize the influence of non-EOC–related deaths. Time-to-event (death or censoring) was calculated from the date of diagnosis. However, cases were recruited at variable times after diagnosis and so time under observation was calculated from date of recruitment (left truncation) in order to prevent the bias that could result from the inclusion of prevalent cases. Effect estimates from left-truncated data are considered to be unbiased if the event time and delayed entry time are independent, given the covariates.24
Differences in tumor stage, grade, histology, and age at diagnosis between BRCA1, BRCA2, and noncarriers were tested using logistic regression adjusted for study site. We used Cox proportional hazards regression models to estimate hazard ratios (HR) and 95% CIs. All models were adjusted for year of EOC diagnosis (<1990, 1990-1995, 1996-2000, and 2000-2010) and stratified by study site. In stratified survival analyses, strata with small numbers of deaths can lead to unreliable estimates. For this reason, 4 studies with less than 30 cases were placed in the same strata as other studies sharing similar study designs and baseline survival rates.
We performed analyses with and without adjustment for stage, grade, histology, and age at diagnosis. The Cox proportional hazards assumption was tested for each covariate analytically using Schoenfeld residuals. Age at diagnosis and histology violated the proportional hazards assumption; therefore, additional covariates were included to allow for time-dependent effects.
Differences in the HR estimates for the survival effect of BRCA1 and BRCA2 by different clinical factors were tested using Cochrane χ2 test (Q-test) for heterogeneity. To assess the effect of possible competing mortality from breast cancer on effect estimates, we compared analyses restricted to women with and without a diagnosis of breast cancer before or in the 5 years following EOC diagnosis. We tested for heterogeneity by study in the HR estimates through the inclusion of an interaction term between study and BRCA1/2 mutation status.
Some participants were missing data for stage (19%), grade (22%), and histology (5%). To decrease potential bias and loss of power due to missingness, we performed multiple imputation for these 3 variables (eMethods). All analyses, except for comparison of pathological characteristics and Kaplan-Meier estimation of survival, were performed on the imputed data. The results using nonimputed data were similar to those presented herein using imputed data. For comparison, the main results using nonimputed data are shown in eTable 2. All analyses were performed using STATA/SE version 11 (StataCorp). Statistical significance was defined as P < .05. Statistical tests were 2 sided.
Data were available for 3879 EOC cases (909 BRCA1 and 304 BRCA2 mutation carriers and 2666 noncarriers). The median number of months from ascertainment to diagnosis for participants was 1 month (interquartile range, 0-15 months). Women were under active follow-up for a median time of 38 months (interquartile range, 18-77 months). The proportion of cases with censored survival time (not followed up to death or 5 years after diagnosis) was 15%. After controlling for study site, there was no significant difference in the proportion of cases with censored survival time among BRCA1 (P = .22) or BRCA2 (P = .41) carriers compared with noncarriers. The median year of EOC diagnosis was 1998 (range, 1981-2010). During the 5 years following EOC diagnosis, 1766 deaths occurred.
Several significant differences in the clinical features of BRCA1 and BRCA2 carriers compared with noncarriers were found (Table 1). Tumors in BRCA1 and BRCA2 carriers were more likely to be of serous histology and less likely to be of mucinous histology than tumors in noncarriers. BRCA1 and BRCA2 carriers were more likely to have stage III/IV tumors and poorly differentiated or undifferentiated tumors than noncarriers. Compared with BRCA1 carriers, BRCA2 carriers were more likely to have stage III/IV tumors. Although BRCA1 carriers were younger at diagnosis than noncarriers, BRCA2 carriers were slightly older.
The 5-year overall survival was 36% (95% CI, 34%-38%) for noncarriers, 44% (95% CI, 40%-48%) for BRCA1 carriers, and 52% (95% CI, 46%-58%) for BRCA2 carriers (Figure and eFigure). In a Cox proportional hazards regression model only adjusted for study site and year of diagnosis, BRCA1 carriers showed a more favorable survival than noncarriers did (HR, 0.78; 95% CI, 0.68-0.89; P < .001) (Table 2). This improved slightly after additional adjustment for stage, grade, histology, and age at diagnosis (HR, 0.73; 95% CI, 0.64-0.84; P < .001). BRCA2 carriers showed a greater survival advantage compared with noncarriers (HR, 0.61; 95% CI, 0.50-0.76; P < .001), particularly after adjusting for other prognostic factors (HR, 0.49; 95% CI, 0.39-0.61; P < .001). The BRCA1 HR estimates were significantly different from the BRCA2 HR estimates in unadjusted (P for heterogeneity = .05) and adjusted models (P for heterogeneity = .003).
We studied the effect of BRCA1/2 mutation status on all-cause mortality after stratifying patients by other clinical features (Table 3). In analyses stratified by grade and adjusted for other prognostic factors, the HRs were more than 1 for both BRCA1 vs noncarriers and BRCA2 vs noncarriers in low-grade cases but less than 1 in high-grade cases. No significant differences were found in the HRs for BRCA1 vs noncarriers or BRCA2 vs noncarriers when stratified according to tumor stage, histology, or history of breast cancer before or during the study period. The survival advantage of BRCA1 and BRCA2 carriers compared with noncarriers was found to be attenuated in women with ovarian cancer selected based on family history of ovarian, breast cancer, or both (Table 4). However, the difference in survival between BRCA1 and BRCA2 carriers did not depend on ascertainment (for BRCA2 vs BRCA1: HR, 0.71; 95% CI, 0.52-0.98; and for familial and unselected cases: HR, 0.64; 95% CI, 0.45-0.91; P for heterogeneity = .65). There was no evidence of study-specific heterogeneity in the HR estimates for mutation status among family-based studies (BRCA1, P = .22; and BRCA2, P = .92) or unselected studies (BRCA1, P = .73; and BRCA2, P = .57).
The proportion of mutation carriers with the Ashkenazi Jewish founder mutations 185delAG and 5382insC in BRCA1 and 6174delT in BRCA2 was 26%. We did not find any significant differences in the adjusted HRs for BRCA1 vs noncarriers among carriers by mutation type (class I vs class II mutation, P for heterogeneity = .10). However, the survival advantage of BRCA1 mutation carriers with class I mutations differed depending on mutation location; worse survival was associated with mutations on the 5′ end compared with the 3′ end of BRCA1 (P for heterogeneity = .03) (eMethods and eTable 3).
A subset of 1129 patients had information on residual disease following primary surgery. We assessed the effect of lack of adjustment for these variables in our main analysis by comparing results with and without adjustment for residual disease in this subgroup. Optimal debulking occurred in 85% of noncarriers, 87% of BRCA1 carriers, and 91% of BRCA2 carriers. After adjusting for study site and year of diagnosis, there was no significant difference in the likelihood of optimal debulking between noncarriers and BRCA1 (P = .74) or BRCA2 (P = .46) carriers. Adjustment for residual disease did not substantially change the HR estimates for the relative survival of either BRCA1 or BRCA2 carriers compared with noncarriers (eTable 4).
Our data demonstrate an improved survival in patients with EOC with germline BRCA1 and BRCA2 mutations relative to noncarriers, with BRCA2 carriers having the best prognosis. BRCA1 carriers presented with EOC at an earlier age than BRCA2 carriers, which is consistent with the age-specific penetrances for BRCA1 compared with BRCA2 carriers. The pathological characteristics of BRCA1 - and BRCA2 -related tumors are similar to each other, but differ from those of tumors in noncarriers. This contrasts with breast cancer, in which substantial differences between BRCA1 - and BRCA2 -associated disease are present.25,26 The differences in grade, stage, and histology by mutation status are consistent with previously reported data.5,27 The effect of BRCA1 and BRCA2 mutations on survival appeared to be similar among patients with both localized and advanced stage tumors and among both serous and nonserous tumors. The lack of a survival advantage for BRCA1 and BRCA2 mutation carriers with low-grade disease suggests that disruptions of the BRCA1/2 pathways may not be as important in the etiology of these tumors, supporting evidence of etiologic heterogeneity between high-grade and low-grade serous carcinoma from other studies.28,29 However, these results were based on small numbers and require confirmation in larger studies.
Our findings confirm the findings of recent analysis of data from The Cancer Genome Atlas (TCGA) project, which reported an improved prognosis for BRCA2 carriers.8 In contrast, we also found an improved prognosis for BRCA1 carriers, whereas the TCGA data suggested no difference between BRCA1 carriers and noncarriers. The most likely reason for this difference is the lack of power to detect a moderate difference in survival in the TCGA data. Indeed, the HR for BRCA1 carriers compared with noncarriers reported by Yang et al8 (multivariate-adjusted HR, 0.76) was very similar to that from our analysis (multivariate-adjusted HR, 0.73).
We found a smaller survival effect of BRCA1 and BRCA2 in the subset of studies in which participants were selected based on a strong family history of ovarian, breast cancer, or both. This could have been due to misclassification of noncarriers in these studies. The sensitivity of mutation testing is likely to be similar across all studies, but the proportion of false-negative carriers will be higher in familial cases. Alternatively, cases from BRCA1/2 wild-type families could carry germline mutations in genes in the same pathway as BRCA1/2 (such as RAD51C30) or in different pathways that produce similar clinical features.
The improved survival of BRCA1/2 carriers relative to noncarriers, and the survival advantage of BRCA2 carriers relative to BRCA1 carriers, could be related to intrinsic biological differences, their response to therapeutic agents, or both. In addition to differences in stage, grade, and histology, BRCA1/2 carriers could have differences in other aspects of tumor biology that were not measured in our study. For example, BRCA1 and BRCA2 carriers have been recently shown to differ from each other and from sporadic EOC in the incidence of visceral metastasis.31
The most notable advantage as well as disadvantage of our study is the fact that it is based on a heterogeneous population; these data were taken from studies containing different ethnic groups, using different mutation screening methodologies and case ascertainment. By including a wide variety of studies, we were able to generate a large enough sample size to adequately address the issue of heterogeneity of the survival effect between BRCA1 and BRCA2 carriers. However, differences in study design and population may limit the specificity of the conclusions drawn. Additionally, varying levels of misclassification of BRCA status and other variables of interest may have led to some bias of our estimates toward the null. However, the absence of heterogeneity in study-specific effects (after accounting for selection on family history) suggests that these results are generalizable to many populations. Furthermore, the magnitude of the differences we observed between BRCA1 and BRCA2 carriers and noncarriers, despite the presence of heterogeneity, provide further testament to their robustness. Even at the lower bounds of our effect estimates, BRCA2 carriers would be predicted to show a 64% decreased risk of death in the 5 years following diagnosis compared with noncarriers.
Our findings could have relevance to an even higher proportion of patients with EOC if somatic mutations and epigenetic silencing of BRCA1 and BRCA2 show similar effects on prognosis to germline mutations. It has been estimated that approximately 30% of EOC and more than 50% of high-grade serous EOC could show dysfunction of BRCA1 or BRCA2 through genetic or epigenetic events.32,33 There is evidence that EOC cases with somatic BRCA1/2 mutations show a survival advantage over noncarriers,33 but data from TCGA and others suggest that silencing of BRCA1 through promoter methylation does not result in an improved overall survival.34,35 Larger studies that include comprehensive genomic screening of BRCA1 and BRCA2 in primary EOCs will be needed to determine if alterations at the somatic and epigenetic level have similar clinical effects to germline mutations.
Our study results have potentially important implications for the clinical management of patients with EOC. Most immediately, our findings can be used by health care professionals for patient counseling regarding expected survival. BRCA1 and BRCA2 carriers with EOC respond better than noncarriers to platinum-based chemotherapies and have improved survival despite the fact that the disease is generally diagnosed at a later stage and higher grade. If patients could be stratified based on their BRCA status, their treatment could be tailored to reflect this, with noncarriers targeted for more aggressive treatments. Our data provide further support that there may be different functional mechanisms involved in the etiology of different subtypes of EOCs and, therefore, different therapeutic targets based on germline and somatic genetic variation. For example, the functional characterization of BRCA1 and BRCA2 led to the development of a novel therapy in BRCA1/2 carriers based on inhibition of the poly (ADP-ribose) polymerase DNA repair pathway, creating a synthetic lethal phenotype. Recently, phase 1 and 2 trials have shown anti-tumor activity of the poly (ADP-ribose) polymerase inhibitor Olparib in BRCA1/2 mutation carriers with EOC.15,36,37 These trials were not large enough to detect differences in response to Olparib in BRCA1 vs BRCA2 carriers and it is not known whether they will show similar levels of response. Epithelial ovarian cancer clinical trials should be stratified by BRCA status, not only to more appropriately target therapy but also to avoid the potential bias introduced by unequal numbers of carriers in treatment groups or between study cohorts. Furthermore, given the important prognostic information provided by BRCA1 and BRCA2 status and the potential for personalized treatment in carriers, the routine testing of women presenting with high-grade serous EOC may now be warranted.
Corresponding Author: Paul D. P. Pharoah, PhD, Departments of Oncology and Public Health and Primary Care, University of Cambridge, Strangeway's Research Laboratory, Wort's Causeway, Cambridge CB1 8RN, England (firstname.lastname@example.org).
Author Contributions: Dr Bolton had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Bolton, Pharoah.
Acquisition of data: Bolton, Chenevix-Trench, Goh, Sadetzki, Ramus, Karlan, Lambrechts, Despierre, Barrowdale, McGuffog, Healey, Easton, Sinilnikova, Benítez, García, Neuhausen, Gail, Hartge, Peock, Frost, Evans, Eeles, Godwin, Daly, Kwong, Ma, Lázaro, Blanco, Montagna, D’Andrea, Nicoletto, Johnatty, Kjær, Jensen, Høgdall, Goode, Fridley, Loud, Greene, Mai, Chetrit, Lubin, Hirsh-Yechezkel, Glendon, Andrulis, Toland, Senter, Gore, Gourley, Michie, Song, Tyrer, Whittemore, McGuire, Sieh, Kristoffersson, Olsson, Borg, Levine, Steele, Beattie, Chan, Nussbaum, Moysich, Gross, Cass, Walsh, Li, Leuchter, Gordon, Garcia-Closas, Gayther, Chanock, Antoniou, Pharoah.
Analysis and interpretation of data: Bolton, Pharoah.
Drafting of the manuscript: Bolton, Gayther, Pharoah.
Critical revision of the manuscript for important intellectual content: Bolton, Chenevix-Trench, Goh, Sadetzki, Ramus, Karlan, Lambrechts, Despierre, Barrowdale, McGuffog, Healey, Easton, Sinilnikova, Benítez, García, Neuhausen, Gail, Hartge, Peock, Frost, Evans, Eeles, Godwin, Daly, Kwong, Ma, Lázaro, Blanco, Montagna, D’Andrea, Nicoletto, Johnatty, Kjær, Jensen, Høgdall, Goode, Fridley, Loud, Greene, Mai, Chetrit, Lubin, Hirsh-Yechezkel, Glendon, Andrulis, Toland, Senter, Gore, Gourley, Michie, Song, Tyrer, Whittemore, McGuire, Sieh, Kristoffersson, Olsson, Borg, Levine, Steele, Beattie, Chan, Nussbaum, Moysich, Gross, Cass, Walsh, Li, Leuchter, Gordon, Garcia-Closas, Gayther, Chanock, Antoniou, Pharoah.
Statistical analysis: Bolton, Goh, Gail, Tyrer, Pharoah.
Obtained funding: Chenevix-Trench, Easton, Gayther, Chanock, Antoniou, Pharoah.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Easton reported serving on the board of Genome Canada SIAC. Dr Godwin reported receiving consultancy fees from TetraLogic and Pfizer and grants from Merck, TetraLogic, and Millennium. Dr Gourley reported receiving consultancy fees from Roche, Schering-Plough, Merck Sharpe Dohme, Chugia, GlaxoSmithKline, and PharmaMar; receiving grants from AstraZeneca, GlaxoSmithKline, and Cyclacel; serving as a board member for Roche, Schering-Plough, and Chugai; receiving payment for lectures and educational presentations from Chugai and Merck Sharpe Dohme; and receiving compensation for travel expenses from Schering-Plough, Chugai, PharmaMar, Roche, and Boehringer Ingelheim. Dr Olsson reported receiving payment for lectures from NovoNordisk. Dr Nussbaum reported serving on the board and receiving consultancy fees and stock from Complete Genomics Inc. No other authors reported any disclosures.
A full list of principal investigators and participating centers for EMBRACE has been published (Hum Mol Genet. 2010;19(14):2886-2897).
Members of the kConFab Investigators:Peter MacCallum Cancer Center, East Melbourne, Australia: Stephen Fox, MD; Ian Campbell, PhD; Melissa Brown, PhD; Gerda Evans; Judy Kirk: Westmead Hospital, MD, PhD; Sunil Lakhani, MD; Geoff Lindeman, MD, PhD; Gillian Mitchell, MD, PhD; Kelly Phillips, MD; Melanie Price, PhD; Christobel Saunders, MD; Mandy Spurdle, PhD; Graeme Suthers, MD, PhD; Roger Milne, PhD.
A full list of principal investigators and participating centers for The Cancer Genome Atlas Research Network has been published (Nature. 2011;474(7353):609-615).
Funding/Support: This work was supported by grants C490/A10119, C490/A10124, C1287/A10118, C1287/A11990, C5047/A8385 from Cancer Research UK; grants 223175, HEALTH-F2-2009-223175 from the Edinburgh Experimental Cancer Medicine Center, the European Community's Seventh Framework Program; grants PS09/01094 and PI081120 from the Fondo de Investigación Sanitaria; grant AP-8101-2010 from the Fundación Mutua Madrileña; grants CA 74415, CA 61126-03, R01-CA 61107, R01-CA 122443, P50 CA 136393, P01 CA 130818, 2P50 CA 058207, and the Intramural Research Program of the National Cancer Institute, DCEG from the Melville Trust for the Care and Cure of Cancer, National Institutes of Health; the Nationaal Kankerplan–Actie 29' of Belgium; the NHMRC of Australia; the National Breast Cancer Foundation of Australia, Cancer Australia (628333); the Queensland Cancer Fund; the Cancer Councils of New South Wales, Victoria, Tasmania, and South Australia; the Cancer Foundation of Western Australia; the Scottish Funding Council; the Scottish Chief Scientist's Office; the Manchester NIHR Biomedical Research Center; Minnesota Ovarian Cancer Alliance; Fred C. and Katherine B. Andersen Foundation; Mermaid 1 project; the Danish Cancer Society; Ministero dell'Istruzione, dell'Università e della Ricerca and Ministero della Salute (“Progetto Tumori Femminili” and RFPS 2006-5-341353, ACC2/R6.9”); the Israeli Cancer Association; the Helen Diller Family Comprehensive Cancer Center at University of California San Francisco; the Avon Foundation; The Hong Kong Hereditary Breast Cancer Family Registry and the Dr Ellen Li Charitable Foundation; and service grants NO2-CP-11019-50 and N02-CP-65504 (with Westat, Inc, Rockville, MD) through the National Cancer Institute; Asociación Española Contra el Cáncer, Spanish Health Research Fund; Carlos III Health Institute; and grants ISCIIIRETIC RD06/0020/1051, PI10/01422, PI10/31488, and 2009SGR290 from the Catalan Health Institute and Autonomous Government of Catalonia. Dr Karlan is supported by funding (grant SIOP-06-258-06-COUN) from the American Cancer Society, Clinical Research Professorship. Dr García is the recipient of a Miguel Servet contract from the Instituto de Salud Carlos III. Dr Antoniou is a Cancer Research UK Senior Cancer Research Fellow.
Role of the Sponsors: None of the sponsors described above had any role in the design or conduct of the study, in the collection, analysis, and interpretation of the data, or in the preparation, review, or approval of the manuscript.
Additional Contributions: We thank all the patients and families who took part in the component studies and the many individuals who have made these studies possible. John Stratton, PhD, and Vickie Basham, BA, provided help in collecting and managing data from the UK Gilda Radner Familial Ovarian Cancer Registry study. Heather Thorne, BSci (Professional Diploma in Clinical Research), and Eveline Niedermayr, BSc (G.Dip. Information Management, G.Dip. Software Development), provided help in collecting and managing data for the Kathleen Cuningham Consortium for Research into Familial Breast Cancer study. None of the individuals acknowledged herein received specific compensation for their role in the manuscript.