Revisiting the Implications of Positive Germline Testing Results Using Multi-gene Panels in Breast Cancer Patients

BACKGROUND/AIM

The use of multi-gene panels for germline testing in breast cancer enables the estimation of cancer risk and guides risk-reducing management options. The aim of this study was to present data that demonstrate the different levels of actionability for multi-gene panels used in genetic testing of breast cancer patients and their family members.

MATERIALS AND METHODS

We performed an analysis in our clinical database to identify breast cancer patients undergoing genetic testing. We reviewed positive results in respect of risk estimation and management, cascade family testing, secondary findings and information for treatment decision-making.

RESULTS

A total of 415 positive test reports were identified with 57.1%, 18.1%, 10.8% and 13.5% of individuals having pathogenic/likely pathogenic variants in high, moderate, low and with insufficient evidence for breast cancer risk genes, respectively. Six point seven percent of individuals were double heterozygotes.

CONCLUSION

Germline findings in 92% of individuals are linked to evidence-based treatment information and risk estimates for predisposition to breast and/or other cancer types. The use of germline findings for treatment decision making expands the indication of genetic testing to include individuals that could benefit from targeted treatments.

Analysis of hereditary cancer syndromes by using a panel of genes: novel and multiple pathogenic mutations

Background

Hereditary cancer predisposition syndromes are responsible for approximately 5–10% of all diagnosed cancer cases. In the past, single-gene analysis of specific high risk genes was used for the determination of the genetic cause of cancer heritability in certain families. The application of Next Generation Sequencing (NGS) technology has facilitated multigene panel analysis and is widely used in clinical practice, for the identification of individuals with cancer predisposing gene variants. The purpose of this study was to investigate the extent and nature of variants in genes implicated in hereditary cancer predisposition in individuals referred for testing in our laboratory.

Methods

In total, 1197 individuals from Greece, Romania and Turkey were referred to our laboratory for genetic testing in the past 4 years. The majority of referrals included individuals with personal of family history of breast and/or ovarian cancer. The analysis of genes involved in hereditary cancer predisposition was performed using a NGS approach. Genomic DNA was enriched for targeted regions of 36 genes and sequencing was carried out using the Illumina NGS technology. The presence of large genomic rearrangements (LGRs) was investigated by computational analysis and Multiplex Ligation-dependent Probe Amplification (MLPA).

Results

A pathogenic variant was identified in 264 of 1197 individuals (22.1%) analyzed while a variant of uncertain significance (VUS) was identified in 34.8% of cases. Clinically significant variants were identified in 29 of the 36 genes analyzed. Concerning the mutation distribution among individuals with positive findings, 43.6% were located in the BRCA1/2 genes whereas 21.6, 19.9, and 15.0% in other high, moderate and low risk genes respectively. Notably, 25 of the 264 positive individuals (9.5%) carried clinically significant variants in two different genes and 6.1% had a LGR.

Conclusions

In our cohort, analysis of all the genes in the panel allowed the identification of 4.3 and 8.1% additional pathogenic variants in other high or moderate/low risk genes, respectively, enabling personalized management decisions for these individuals and supporting the clinical significance of multigene panel analysis in hereditary cancer predisposition.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5756-4) contains supplementary material, which is available to authorized users.

Abstract P4-03-07: Analysis of hereditary cancer syndromes by using a panel of genes: Novel and multiple pathogenic mutations

BACKGOUND: Hereditary cancer predisposition syndromes are believed to be responsible for approximately 5-10% of all diagnosed cancer cases. In the past, single genes analysis of certain high risk genes was used for the determination of the genetic cause of cancer heritability in certain families. The selection of genes was mainly based on the family history of the individuals analyzed and included only highly associated genes (e.g. the BRCA1 and BRCA2 genes for families with breast cancer history. Nowadays though, the application of Next Generation Sequencing (NGS) technology has facilitated multigene panel analysis and is widely used in clinical practice, for the identification of individuals with cancer predisposition gene mutations.

AIM: The aim of this study was to investigate the extent and nature of mutations in 36 genes implicated in hereditary cancer predisposition in individuals referred for testing in our lab.

MATERIALS & METHODS: In total, 1197 individuals were referred for testing in our lab in the past four years from Greece, Romania and Turkey. The analysis of genes involved in hereditary cancer predisposition was performed using two NGS approaches. The first 451 individuals were analyzed using an amplicon based sequencing method (26 gene panel), while the following 746 individuals were analyzed using a capture based method (33 gene panel). Genomic DNA was enriched for targeted regions of 36 genes involved in hereditary predisposition to cancer included in both versions of the panel (APC, BMPR1A, BRCA1, BRCA2, CDH1, CDK4, CDKN2A, EPCAM, MEN1, MLH1, MSH2, MSH6, MUTYH, PALB2, PMS2, PTEN, RET, SMAD4, STK11, TP53, VHL, ATM, BRIP1, CHEK2, NBN, RAD51C, RAD51D, BARD1, BLM, CHEK1, ABRAXAS1 (FAM175A), MRE11 (MRE11A), NF1, RAD50, RAD51B, XRCC2). Sequencing was carried out using the Illumina NGS technology. Reads were aligned to the reference sequence (GRCh37), and sequence changes were identified and interpreted in the context of a single clinically relevant transcript. The presence of large genomic rearrangements was investigated by computational analysis of NGS results and the use of MLPA for 13 genes. All clinically significant observations were confirmed by orthogonal technologies.

RESULTS: In total, a pathogenic mutation was identified in 259 of the 1197 individuals (21.6%) analyzed while a VUS was identified in 35.7% of the cases. Clinically significant mutations were identified in 29 of the genes analyzed. Concerning the mutation distribution among individuals with positive findings, 44.7% of them were located in BRCA1/2 genes whereas 20.9%, 19.9%, and 14.5% in high, moderate and low risk genes respectively. In addition to BRCA1 and BRCA2 genes other highly mutated genes were CHEK2 (10.6%), PALB2 (7.1%), MUTYH (7.1%) and ATM (4.3%). Of note is that 25 of the 259 positive individuals (9.7%) carried clinically significant mutations in two different genes and 5.8% had a large genomic rearrangement (LGR).

CONCLUSIONS: Our results support the clinical significance of analysis of a panel of genes involved in hereditary cancer predisposition. In our cohort, analysis of this panel allowed for the identification of 8.3% additional pathogenic variants in moderate/low risk genes, enabling personalized management of these individuals.

Citation Format: Tsoulos N, Tsaousis GN, Papadopoulou E, Agiannitopoulos K, Pepe G, Kambouri S, Apessos A, Diamantopoulos N, Floros T, Iosifidou R, Katopodi O, Koumarianou A, Markopoulos C, Papazisis K, Venizelos V, Xanthakis I, Xepapadakis G, Banu E, Eniu DT, Negru S, Stanculeanu DL, Ungureanu A, Ozmen V, Tansan S, Tekinel M, Yalcin S, Nasioulas G. Analysis of hereditary cancer syndromes by using a panel of genes: Novel and multiple pathogenic mutations [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 P4-03-07.

Access to Genetic Testing Impacts Oncologists´ Decisions on Ovarian Cancer Personalized Treatment: Lessons Learned From a National Program in Greece

Background: State health insurance authorities in Greece do not reimburse genetic testing for cancer predisposition. The Hellenic Society of Medical Oncology has launched and carries out a national program covering genetic testing for BRCA1/2 mutations detection, with the financial support of pharmaceutical industry. Aim: This analysis evaluates how, during this program, access to genetic testing transformed the oncologists' therapeutic approach toward their ovarian cancer patients and how the results impacted treatment decisions concerning PARP inhibitors. Adoption of testing by healthy relatives and timing of testing in the disease continuum were also evaluated. Methods: Adult patients with high-grade epithelial ovarian carcinoma, irrespectively of family history or age at diagnosis were eligible for this program. Genetic counseling was recommended before testing, and both were offered at no financial cost. First degree family members of pathogenic mutation carriers were also offered free counseling and testing. Results: From March 2015 through January 2018, 708 patients were enrolled and tested. One hundred and forty seven (20.7%) mutation carriers were identified, 102 (14.4%) in BRCA1 and 45 (6.3%) in BRCA2 gene. Testing was more often pursued at initial diagnosis (61%) than at recurrence (39%), as recorded for 409 patients with available relevant information. During the 1st year of the program, average monthly tests performed were 25.1, while during the 3rd year this number increased to 34.3 tests per month. Among patients who tested positive for deleterious BRCA1/2 mutations, relapse was reported in 58 patients, 94.8% of which (n= 55) received treatment with the PARP inhibitor olaparib as per its indication. Family members of 21 patients (14.3%), out of the 147 who tested positive, received genetic counseling and testing for the mutation identified in the context of the program. Conclusion: Free access to genetic testing for BRCA1/2 for ovarian cancer patients and genetic consultation facilitates testing uptake, affects common clinical practice & has major impact on patients and their families. Still, diffusion of genetic information and broader testing of family members require further efforts by the oncological community.

Clinical practice guidelines for the management of metastatic colorectal cancer: a consensus statement of the Hellenic Society of Medical Oncologists (HeSMO)

There is discrepancy and failure to adhere to current international guidelines for the management of metastatic colorectal cancer (CRC) in hospitals in Greece and Cyprus. The aim of the present document is to provide a consensus on the multidisciplinary management of metastastic CRC, considering both special characteristics of our Healthcare System and international guidelines. Following discussion and online communication among the members of an executive team chosen by the Hellenic Society of Medical Oncology (HeSMO), a consensus for metastastic CRC disease was developed. Statements were subjected to the Delphi methodology on two voting rounds by invited multidisciplinary international experts on CRC. Statements reaching level of agreement by ≥80% were considered as having achieved large consensus, whereas statements reaching 60-80% moderate consensus. One hundred and nine statements were developed. Ninety experts voted for those statements. The median rate of abstain per statement was 18.5% (range: 0-54%). In the end of the process, all statements achieved a large consensus. The importance of centralization, care by a multidisciplinary team, adherence to guidelines, and personalization is emphasized. R0 resection is the only intervention that may offer substantial improvement in the oncological outcomes.

Clinical practice guidelines for the surgical treatment of rectal cancer: a consensus statement of the Hellenic Society of Medical Oncologists (HeSMO)

In rectal cancer management, accurate staging by magnetic resonance imaging, neo-adjuvant treatment with the use of radiotherapy, and total mesorectal excision have resulted in remarkable improvement in the oncological outcomes. However, there is substantial discrepancy in the therapeutic approach and failure to adhere to international guidelines among different Greek-Cypriot hospitals. The present guidelines aim to aid the multidisciplinary management of rectal cancer, considering both the local special characteristics of our healthcare system and the international relevant agreements (ESMO, EURECCA). Following background discussion and online communication sessions for feedback among the members of an executive team, a consensus rectal cancer management was obtained. Statements were subjected to the Delphi methodology voting system on two rounds to achieve further consensus by invited multidisciplinary international experts on colorectal cancer. Statements were considered of high, moderate or low consensus if they were voted by ≥80%, 60-80%, or <60%, respectively; those obtaining a low consensus level after both voting rounds were rejected. One hundred and two statements were developed and voted by 100 experts. The mean rate of abstention per statement was 12.5% (range: 2-45%). In the end of the process, all statements achieved a high consensus. Guidelines and algorithms of diagnosis and treatment were proposed. The importance of centralization, care by a multidisciplinary team, adherence to guidelines, and personalization is emphasized.

Adjuvant chemotherapy for colon cancer: a consensus statement of the Hellenic and Cypriot Colorectal Cancer Study Group by the HeSMO

Colorectal cancer remains a major cause of cancer mortality in the Western world both in men and women. In this manuscript a concise overview and recommendations on adjuvant chemotherapy in colon cancer are presented. An executive team from the Hellenic Society of Medical Oncology was assigned to develop a consensus statement and guidelines on the adjuvant treatment of colon cancer. Fourteen statements on adjuvant treatment were subjected to the Delphi methodology. Voting experts were 68. All statements achieved a rate of consensus above than 80% (>87%) and none revised and entered to a second round of voting. Three and 8 of them achieved a 100 and an over than 90% consensus, respectively. These statements describe evaluations of therapies in clinical practice. They could be considered as general guidelines based on best available evidence for assistance in treatment decision-making. Furthermore, they serve to identify questions and targets for further research and the settings in which investigational therapy could be considered.

Clinical practice guidelines for the surgical management of colon cancer: a consensus statement of the Hellenic and Cypriot Colorectal Cancer Study Group by the HeSMO

Despite considerable improvement in the management of colon cancer, there is a great deal of variation in the outcomes among European countries, and in particular among different hospital centers in Greece and Cyprus. Discrepancy in the approach strategies and lack of adherence to guidelines for the management of colon cancer may explain the situation. The aim was to elaborate a consensus on the multidisciplinary management of colon cancer, based on European guidelines (ESMO and EURECCA), and also taking into account local special characteristics of our healthcare system. Following discussion and online communication among members of an executive team, a consensus was developed. Statements entered the Delphi voting system on two rounds to achieve consensus by multidisciplinary international experts. Statements with an agreement rate of ≥80% achieved a large consensus, while those with an agreement rate of 60-80% a moderate consensus. Statements achieving an agreement of <60% after both rounds were rejected and not presented. Sixty statements on the management of colon cancer were subjected to the Delphi methodology. Voting experts were 109. The median rate of abstain per statement was 10% (range: 0-41%). In the end of the voting process, all statements achieved a consensus by more than 80% of the experts. A consensus on the management of colon cancer was developed by applying the Delphi methodology. Guidelines are proposed along with algorithms of diagnosis and treatment. The importance of centralization, care by a multidisciplinary team, and adherence to guidelines is emphasized.