Devanshi Patel

Endoscopic Surveillance of Patients With Hereditary Diffuse Gastric Cancer: Biopsy Recommendations After Topographic Distribution of Cancer Foci in a Series of 10 cdh1 -mutated Gastrectomies

The management of hereditary diffuse-type gastric cancer revolves around surveillance biopsies and the timing of prophylactic gastrectomy. In the absence of a validated surveillance biopsy protocol, we modeled bioptic diagnostic yield on the basis of the topographic distribution of cancer foci in a series of 10 gastrectomies in CDH1-mutation carriers. Complete histologic examination was performed in all cases, and 1817 slides were evaluated for the presence of in situ, intramucosal, or submucosal diffuse-type carcinoma. Detailed maps determined the density of cancer foci. On the basis of the number of sampled glands per biopsy in routine surveillance preoperative endoscopy, we estimated the theoretical number of biopsies necessary for a 90% rate of detection of neoplastic foci, and we evaluated this number, taking into account the regional distribution of these foci. A total of 96 m of gastric mucosa with ∼1,193,453 gastric glands yielded 302 cancer foci [in situ (n=89), intramucosal (n=209), and submucosal (n=4)] spanning the width of a total of 1820 glands (8 to 1205 per case; average 182±115). On the basis of the number of glands per stomach and the average number of glands sampled during surveillance biopsy (28.7±1.7; range, 0 to 79; n=112), the theoretical number of biopsies necessary to capture at least 1 cancer focus was estimated to be 1768 (range, 50 to 5832) to assure a 90% detection rate. Mapping of cancer foci showed the highest density in the anterior proximal fundus (37%) and cardia/proximal fundus (27%). Our results argue for the incorporation of cancer focus distribution into any biopsy protocol, although detection is likely to remain extremely low, and they call into question the validity of endoscopic surveillance.

Estimating CDKN2A Carrier Probability and Personalizing Cancer Risk Assessments in Hereditary Melanoma Using MelaPRO

Personalized cancer risk assessment remains an essential imperative in postgenomic cancer medicine. In hereditary melanoma, germline CDKN2A mutations have been reproducibly identified in melanoma-prone kindreds worldwide. However, genetic risk counseling for hereditary melanoma remains clinically challenging. To address this challenge, we developed and validated MelaPRO, an algorithm that provides germline CDKN2A mutation probabilities and melanoma risk to individuals from melanoma-prone families. MelaPRO builds on comprehensive genetic information, and uses Mendelian modeling to provide fine resolution and high accuracy. In an independent validation of 195 individuals from 167 families, MelaPRO exhibited good discrimination with a concordance index (C) of 0.86 [95% confidence intervals (95% CI), 0.75-0.97] and good calibration, with no significant difference between observed and predicted carriers (26; 95% CI, 20-35, as compared with 22 observed). In cross-validation, MelaPRO outperformed the existing predictive model MELPREDICT (C, 0.82; 95% CI, 0.61-0.93), with a difference of 0.05 (95% CI, 0.007-0.17). MelaPRO is a clinically accessible tool that can effectively provide personalized risk counseling for all members of hereditary melanoma families.

Professional Challenges in Cancer Genetic Testing: Who Is the Patient?

In the genetic counseling setting, the health care provider can be challenged by opposing duties to members of the same family: protecting the privacy of the patient identified with a gene mutation and the ethical obligation to warn at-risk relatives. In a situation of nondisclosure between members of a family with a known disease-predisposing mutation, this type of dilemma can present in acute form for the provider who cares for different members of the family. This can hinder effective medical decision making. To minimize this effect, we recommend detailed pretest genetic counseling steps to empower the patient to communicate with their at-risk relatives their intent to pursue testing and willingness to share information. In addition, post-test counseling should reiterate the implications of a positive result for at-risk relatives and conclude with a written summary that patients can share with their family.

Clinical Applications of Melanoma Genetics

Opinion statementFamilies that have several relatives with melanoma, multiple primary melanomas in one individual, younger than average ages of melanoma onset, and/or the presence of both pancreatic cancer and melanoma may be suggestive of a hereditary melanoma syndrome and are candidates for genetic counseling and risk assessment. Genetic counseling for hereditary melanoma presents many complexities. Only a minority of hereditary melanoma cases have been attributed to a single genetic factor, CDKN2A. Both the frequency and the penetrance of CDKN2A mutations has been shown to be dependent on multiple factors. The clinical utility of genetic testing for hereditary melanoma families is debatable because CDKN2A status may not impact medical management in patients with melanoma. No standard medical management guidelines exist for families with CDKN2A mutations; however, family history of melanoma and pancreatic cancer may warrant further discussion. Clinicians should discuss the clinical and psychological implications before genetic testing. Genetic counseling and pretest education regarding melanoma risk factors provides an opportunity to increase knowledge and understanding of melanoma risk, while addressing psychological risks and concerns.

Which individuals undergoing BRACAnalysis need BART testing

Deleterious mutations in BRCA1 and BRCA2 include those identified by sequencing technology as well as large genomic rearrangements (LGR). The main testing laboratory in the United States, Myriad Genetics Laboratory (MGL), has defined criteria for inclusion of LGR testing (i.e., BRACAnalysis Rearrangement Test, or BART™) when BRCA1 and BRCA2 testing is ordered. We were interested in determining how many of our patients with LGR mutations in BRCA1 and BRCA2 fulfilled these MGL criteria. A retrospective chart review was performed on all individuals who underwent genetic testing at our institution since August 2006. Individuals who underwent LGR testing were classified as either having or not having a LGR in BRCA1 or BRCA2. Each individuals history was classified as meeting MGL defined LGR criteria, meeting criteria using third-degree relatives, or not meeting criteria. A total of 257 BART tests were ordered at our institution from August 2006 to August 2009. Five individuals (1.9%) had an LGR mutation. Two LGR were identified in patients who met MGL defined LGR criteria. One LGR was identified in a patient that met MGL defined LGR criteria only when using third-degree relatives. Two LGR were identified in individuals who did not meet MGL defined criteria. LGR are present in individuals who do not have a high pretest probability of carrying a mutation in BRCA1 or BRCA2. These data suggest that when BRCA1 and BRCA2 genetic testing is performed, testing should always include LGR testing so that the results are the most comprehensive and reliable.

Principles of Cancer Genetic Counseling and Genetic Testing

Although only 5–10% of all cases of cancer are attributable to a highly penetrant cancer predisposition gene, the identification of individuals at inherited risk for cancer has become an integral part of the practice of predictive and preventative medicine. Identifying those individuals with a significantly higher risk of developing specific cancers allows health-care providers to intervene with appropriate counseling and education, increased cancer surveillance, and sometimes even cancer prevention. This chapter focuses on the identification of patients at high risk for cancer and the importance of referral to genetic counselors and other genetics professionals. The chapter also discusses the intricacies surrounding genetic testing, including the ethical, legal, and social implications of identifying those at increased risk for cancer.

Finding a Balance: Reconciling the Needs of the Institution, Patient, and Genetic Counselor for Optimal Resource Utilization

The current practice of cancer genetic counseling is undergoing widespread change and scrutiny. While there are clinical resources for genetic counselors (GCs) regarding the delivery of cancer genetic services, there is limited literature regarding effective management of a genetic counseling clinical program. We have developed administrative tools to manage a large team of GCs at a single academic medical center over a period of increasing demand for genetics services, with the initial aim of decreasing wait time for urgent genetic counseling visits. Here, we describe the three main elements of the clinical operations: Balancing patient volume between GCs, scheduling tracks for both routine and urgent appointments, and a team of triaging GCs to ensure appropriate patient referrals. For each of these elements, we describe how they have been modified over time and present data to support the utility of these strategies. The preliminary evidence offered here suggests that these tools allow for an equitable distribution of patient volume between team members, as well as the timely and accurate scheduling of urgent patients. As a result of the experiences presented here, other genetic counseling programs grappling with similar issues should be aware that it is possible to shift clinical operations to serve certain patient populations in a more timely fashion while keeping both providers and GC staff satisfied.