Introduction

Breast cancer (BC) is the most common cancer in women, with a 5-year survival rate of >ā€‰90%. More than 3.8 million women in the United States are BC survivors, representing four in ten of all female cancer survivors. As survival has steadily improved, more attention has shifted to BC survivorsā€™ post-treatment needs, including addressing risk and surveillance for second primary malignancies1.

In contrast, pancreatic cancer (PC) is the 3rd leading cause of cancer-related death in the United States, with a dismal 5-year survival rate of 10%. In 2020, approximately 57,600 men and women will be diagnosed with PC and more than 47,050 will die from the disease2. By the time symptoms of PC develop, the cancer is typically advanced and not amenable to surgical resection. For the 15% of patients presenting with localized disease that can be surgically treated, the 5-year survival rate approaches 60ā€“70% for tumors less than 1Ā cm in size3, highlighting the potential value of early detection. Current United States Preventive Services Task Force (USPSTF) recommendations do not support screening for PC in the general population4, but guidelines for screening with MRI/MRCP and endoscopic ultrasound in a defined population at high risk for PC due to family history and/or genetic risk factors exist5,6. Emerging data suggests a benefit in PC screening in this high-risk population, including improved identification of early stage PC, and improved 3-year survival7,8,9. Identifying patients who meet criteria for PC surveillance based on family history and gene status is an important goal for early detection.

Several lines of evidence support a link between BC and PC risk in some families. A cohort analysis of 5799 families with multiple or early onset cases of breast or ovarian cancer demonstrated increased risk of PC in families with pathogenic germline variants (PGVs) in BRCA1 or BRCA210. The study also found elevated PC risk in families negative for BRCA1/2, suggesting that elevated PC risk in BC families was not fully explained by BRCA PGV10. Germline testing identifies a clinically relevant PGV in up to 10% of patients with PC11,12,13,14,15, and one study found that PGVs were more common in PC patients with a history of BC in themselves or a first degree relative14. A caseā€“control study found evidence for an independent association of PC risk with PGVs in six genes: ATM, BRCA1, BRCA2, CDKN2A, MLH1, and TP5316, five of which (excluding CDKN2A) have a clear link to breast cancer risk17,18,19,20. PGVs in PALB2 and STK11 have also been linked to increased risk for both PC and BC21,22,23. Current NCCN clinical practice guidelines recommend consideration of comprehensive testing with a multi-gene panel for BC patients meeting specific testing criteria based on age, hormone receptor status, Ashkenazi Jewish ancestry, and family history criteria, as well as for all PC patients. The guidelines also recommend consideration of multi-gene panel testing for patients meeting criteria who previously tested negative with limited testing (e.g. single gene analysis)24.

The evolving knowledge about underlying PGVs linking BC and PC risk, the utility of multi-gene panel testing, and the emergence of data supporting the benefit of PC screening in high-risk individuals have potential implications for long term care of BC survivors. The purpose of this study was to investigate genetic testing patterns and outcomes, along with reported family history of PC, in a registry population of patients with BC. We sought to better characterize the implications of changing practice guidelines and clinical recommendations for BC survivors, utilizing the specific example of PC risk.

Methods

All newly diagnosed BC patients undergoing definitive surgery enrolled in the NYU Langone Perlmutter Cancer Center Breast Cancer Database between January 2010 and December 2018 were included in the study. Variables of interest included patient demographics (age at BC diagnosis, race), family history of PC in a first or second degree relative, genetic testing type (BRCA1/2 only or multi-gene panel testing defined as any test including additional genes beyond BRCA1 and BRCA2), tumor characteristics, and BC recurrence. All clinical data were obtained from electronic medical record review and detailed questionnaires completed by participating patients. Details of the Breast Cancer Database have been previously described25. This study was approved by the NYU Institutional Review Board, and research was performed in accordance with relevant guidelines/regulations. Patients signed informed consent prior to database enrollment.

Descriptive analyses were used to summarize the data distribution of variables between the patients who had family history of PC compared to those who did not have family history of PC. Statistical analyses included Pearsonā€™s chi-squareĀ and Wilcoxon rank-sum with a significance level of Ī±ā€‰=ā€‰0.05. All analyses were done using SAS software, version 9.4 (SAS Institute).

Results

A total of 3334 BC patients enrolled in the Breast Cancer Database during the 8Ā year study period. Patient demographics and clinical characteristics are shown in Table 1. Among the total BC patient population, 232 (7%) reported a family history of PC in a first or second degree relative. Breast cancer patients with a family history of PC were 1.93 times more likely to be of white race (pā€‰<ā€‰0.001) and 1.68 times more likely to have had genetic testing (56% vs 44%, pā€‰<ā€‰0.001) than those without family history of PC. There were no other significant differences in demographic or clinical variables between patients with and without family history of PC (Table 1). In the 129 patients with FHPC who underwent genetic testing, 15 (11.6%) had PGVs identified, with 9/15 (60%) occurring in genes with a clear link to PC risk. Among BC patients without FHPC, 145/1315 (11.0%) of patients had a PGV identified, with 123/145 (85%) occurring in genes linked to PC risk (Table 2). The majority of BC patients who had genetic testing, with and without family history of PC, had testing for BRCA1 and BRCA2 only (58.9% and 63% respectively) rather than a multi-gene panel.

Table 1 Demographic and clinical characteristics.
Table 2 Genetic testing outcomes in BC patients.

Discussion

In our BC study population of over 3000 patients, 7% of BC patients reported a family history of PC in a first or second degree relative. Genetic testing was completed in 56% of BC patients with FHPC, and 11.6% carried a PGV with clinical relevance. Genes linked to PC risk represented 60% of the findings (BRCA1, BRCA2, and PALB2), and these patients meet current published guidelines recommending PC surveillance with annual imaging beginning at age 50 or 10Ā years younger than the earliest diagnosis of PC in the family5,6. Importantly, several BC patients without a family history of PC at the time of diagnosis also carried PGVs in genes linked to PC risk (ATM, BRCA1, BRCA2, CDKN2A, PALB2, and MLH1). All of these patients would benefit from follow up care that includes updating family history for new PC diagnoses that could impact care, as well as receiving information about changes in PC surveillance recommendations over time.

Our study found that changes in criteria for genetic testing, including expanded age range and added family history components, and the addition of multi-gene panel testing as a recommended approach have potential impact on a majority of BC patients. A substantial proportion of BC patients in the study population, 43% overall, had some type of genetic testing. This proportion is higher than was found in a recent population based analysis of BC patients26, and could reflect the demographic characteristics of our study population which was 28% Ashkenazi Jewish, or differences in utilization at an academic hospital. Despite relatively high test utilization, 44% of BC patients with a family history of PC and 57% of those without family history of PC had no genetic testing of any kind. This lack of testing could be attributed to a variety of reasons, including not being referred for testing by treating physician27,28,29, or declining testing for reasons including cost28,29 or anxiety about potential second primary cancers and impact on future generations30. Another possibility is that patients did not meet testing criteria at the time of the initial diagnosis. NCCN criteria for genetic testing and screening have evolved and expanded over time, and BC survivors could benefit from periodic re-assessment that considers current criteria along with any changes in the family history of cancer. Additionally, the performance of genetic testing guidelines, including NCCN and Medicare guidelines, have come into question with similar PGV detection rates in BC patients who met criteria compared to those who did not31,32. One study found that the sensitivity of NCCN criteria for genetic testing were improved from 70 to 90% by including all women with breast cancer diagnosed under age 6533. Based on this data, the American College of Breast Surgeons put forth a statement in 2019 advocating for offering genetic testing to any BC patient, regardless of age or family history34. This statement would have relevance for the 56% of BC patients in our study who had no testing at all.

Among those in our study who completed genetic testing, 62.6% (41% of those with family history of PC) had testing only for BRCA1 and BRCA2. This could reflect differences in availability and utilization of testing for patients seen 2014ā€“2018 when multi-gene panel testing became more broadly available. This change was brought about by evolution in testing technology decreasing sequencing cost, along with a June, 2013 United States Supreme Court decision invalidating patents on the sequence of BRCA1 and BRCA235,36. While we did not have sufficient data available on exact dates of testing to complete a specific analysis in our population, one study of test utilization in BC patients showed a shift from 74% BRCA1/2 only in 2013 to 33.5% BRCA1/2 only by 201537. NCCN criteria as recently as 2016 continued to recommend specific syndrome testing as the preferred approach, with consideration of multi-gene panel testing only for patients negative for single syndrome testing and with a family history suggestive of inherited cancer risk. Clinical caution in adopting multi-gene panel tests centered primarily on concerns about variants of uncertain significance, and lack of well-characterized risk information and management strategies for several of the low or moderate risk genes included in panels38,39. Additionally, questions about cost effectiveness40 have been addressed over time41,42 allowing insurers to adjust coverage criteria. Multiple studies have now documented additional relevant PGV findings in women with breast cancer offered multi-gene panel testing43,44,45,46. As in our population, the most common genes beyond BRCA1/2 identified on multi-gene panels included several with links to PC risk. Current NCCN guidelines have shifted to recommend consideration of multi-gene panel testing both as a first line test, and for patients previously negative for BRCA1/224. Genetics providers have attempted re-contact of patients via mail to notify them of updated testing, but subsequent test uptake has been very low47,48. Integrating genetic services into cancer survivorship care could help to bridge this gap, and has shown efficacy in a pediatric survivor clinic setting49.

The American Cancer Society and American Society of Clinical Oncology have developed guidelines for survivorship care that address multiple relevant issues for BC survivors including risk evaluation and genetic counseling, as well as screening for second cancers1. These guidelines address the possibility that genetic counseling and genetic testing may not have been offered to a patient meeting criteria, or that family history may have changed leading to a patient meeting criteria who did not at initial diagnosis. In addition, other factors may change, including identification of new susceptibility genes or advances in testing technology, updates to genetic testing criteria, or changes in cancer screening recommendations for individuals with relevant PGVs or family history risk factors50, suggesting the importance of ongoing repeated genetic risk assessment in cancer survivors50. Our findings provide support for this recommendation.

The study has some limitations, including reliance on retrospective analysis of patient-reported family history, which may be incomplete, or may have changed to include new cancer diagnoses since the time of last data collection. This could result in misclassification of BC patients with and without family history of PC. For the purposes of data entry, ā€œmulti-gene panelsā€ included testing for any gene(s) beyond BRCA1/2, and specific information about which genes and total number of genes analyzed was not documented. This could lead to under-identifying the number of patients who could benefit from updated testing. Patients within the NYU Langone Health system may have had later genetic testing at a different institution or with an outside provider that was not shared with their NYU provider and thus not available for our record review. Finally, variants of uncertain significance were not included as part of this data review.

Conclusions

In this study of a large cohort of BC patients who underwent surgical resection, we found that seven percent of BC patients had a positive family history of PC. Of these, 44% did not have genetic testing of any kind and another 33% had testing for only BRCA1/BRCA2 germline mutations, rather than multi-gene panel testing. Based on this data, updates in genetic testing criteria and recommendations for multi-gene panel testing have potential impact on up to 80% of BC survivors. Given the number of known genes associated with risk for both BC and PC, and published recommendations for pancreatic surveillance in carriers of PGV with a family history of PC, patients with BC could benefit from ongoing care to re-evaluate genetic risk and provide updated screening recommendations. This study supports recommendations for survivorship care that incorporates ongoing genetic risk assessment and counseling.