Assessing patient attitudes toward genetic testing for hereditary hematologic malignancy

Since 2003, more than 15 genes have been identified to predispose to hereditary hematologic malignancy (HHM). Although the yield of germline analysis for leukemia appears like that of solid tumors, genetic referrals in adults with leukemia remain underperformed. We assessed leukemia patients' attitudes toward genetic testing and leukemia-related distress through a survey of 1093 patients diagnosed with acute or chronic leukemia, myelodysplastic syndrome, or aplastic anemia. Principal component analysis (PCA) was used to analyze patient attitudes. Distress was measured through the Impact of Event Scale-Revised (IES-R). Exactly 19.8% of eligible respondents completed the survey. The majority reported interest in (77%) or choosing to have (78%) genetic testing for HHM. Slightly over half identified worry about cost of genetic testing (58%) or health insurance coverage (61%) as possible barriers. PCA identified relevant themes of interest in genetic testing, impact on leukemia treatment, discrimination and confidentiality, psychosocial and familial impacts, and cost of testing. The majority reported low distress. Leukemia patients report high interest in genetic testing, few barriers, and relatively low distress.

Understanding the clinical course of genotype-negative MEN1 patients can inform management strategies

BACKGROUND

It is unclear whether genotype-negative clinical multiple endocrine neoplasia type 1 patients derive equal benefit from prospective surveillance as genotype-positive patients.

METHODS

In this retrospective cohort study, we compared genotype-negative patients with clinical multiple endocrine neoplasia type 1 with genotype-positive index cases. Primary outcome was age-related penetrance of manifestations; secondary outcomes were disease-specific survival and clinical course of endocrine tumors.

RESULTS

We included 39 genotype-negative patients with clinical multiple endocrine neoplasia type 1 (Male: 33%) and 63 genotype-positive multiple endocrine neoplasia type 1 index cases (Male: 59%). Genotype-negative patients with clinical multiple endocrine neoplasia type 1 were 65 years old at last follow-up; genotype-positive multiple endocrine neoplasia type 1 index cases were 50 (P < .001). Genotype-negative patients with clinical multiple endocrine neoplasia type 1 were significantly older at their first and second primary manifestation. Only 1 developed a third primary manifestation. No genotype-negative patients with clinical multiple endocrine neoplasia type 1 with primary hyperparathyroidism and a pituitary adenoma developed a duodenopancreatic neuroendocrine tumor. Disease-specific survival was significantly better in genotype-negative patients with clinical multiple endocrine neoplasia type 1. In genotype-negative patients with clinical multiple endocrine neoplasia type 1, primary hyperparathyroidism was single-gland disease in 47% of parathyroidectomies versus 0% in genotype-positive multiple endocrine neoplasia type 1 index cases. In genotype-negative patients with clinical multiple endocrine neoplasia type 1, 17% of duodenopancreatic neuroendocrine tumors were multifocal versus 68% in genotype-positive multiple endocrine neoplasia type 1 index cases. Genotype-negative patients with clinical multiple endocrine neoplasia type 1 had more pituitary macroadenomas, fewer prolactinomas, and more somatotroph adenomas.

CONCLUSION

Genotype-negative patients with clinical multiple endocrine neoplasia type 1 have a different clinical course than genotype-positive multiple endocrine neoplasia type 1 index cases. This may support a separate classification and a tailored surveillance regimen. Of the genotype-negative patients with clinical multiple endocrine neoplasia type 1 who had parathyroidectomy, almost half had no evidence of multigland disease and may be potential candidates for a more targeted single-gland approach.

MON-LB015 Sporadic MTC in Children: Characterization of a Rare Disease

INTRODUCTION: Medullary thyroid carcinoma (MTC) is rare in children and is hereditary (hMTC), caused by germline mutations in the RET proto-oncogene, in about 95% of cases. Very little is known about sporadic MTC (sMTC) when diagnosed in children/young adults. Our aim was to study the clinical presentation and long-term outcomes of a large cohort of sMTC seen at a tertiary cancer center and to compare sMTC with hMTC in young patients (pts).

METHODS: Through a review of institutional databases, we identified pts diagnosed with MTC ≤ age 21 years (y.). Charts were retrospectively reviewed and data abstracted. The diagnosis of sMTC vs hMTC was determined based on germline RET testing and family history.

RESULTS: We identified 146 pts (53% female), of whom 20 (14%) had sMTC and 126 (86%) had hMTC (80 MEN2a and 46 MEN2b), with a median follow-up of 10 y. (range: 0.08-58, IQR 4.8-18). In pts with sMTC, the stage at diagnosis was I-II in 3/15 (20%) and stage III-IV in 12/15 (80%). Somatic mutations were identified in 11/12 tumors tested (6 RET p.M918T, 1 RET p.G691S, 2 RET deletions p.L629_L633del and p.E632_L633del, 1 RET c.2698_2710delinsC, and 1 CCDC6-ALK fusion). In contrast to hMTC, pts with sMTC were diagnosed at an older age [mean 18.0 y. ± 3.4 (range: 10-21) vs 12.9 y. ± 5.4 (range: 1.5-21), p<0.001], had higher calcitonin [median 889 (IQR 528-2634) vs 16 (IQR 3-117) x Upper Limit of Normal, p<0.001] and CEA levels [median 186 (IQR 46-468) vs 11 (IQR 4-16) x Upper Limit of Normal, p<0.001], larger tumors [median 2.5 cm (IQR 2-3.7) vs. 0.8 cm (IQR 0.4-1.9), p<0.001], and were more likely to be stage IV at diagnosis [73% vs 28%, p<0.001]. sMTC pts were less likely to have bilateral tumors [27% vs 81%, p<0.001] and, at last follow-up, had more persistent structural disease [79% vs 46%, p=0.007] and distant metastases [74% vs 37%, p=0.005]. Death from MTC occurred in 15% of pts with sMTC vs 6% pts with hMTC; median overall survival was not significantly different [30.6 y. in sMTC vs 39.3 y. in hMTC].

CONCLUSION: In this largest reported series of MTC in children/young adults, and the only study to look at sMTC in this population, we identified sMTC in 14% of MTC cases, a higher prevalence than is traditionally recognized but one that is possibly confounded by a referral bias. Somatic mutations were identified in 92% of samples tested, allowing for targeted therapy in those with distant metastases if needed. Compared with hMTC, patients with sMTC presented at an older age with higher tumor markers, larger tumors, and more unilateral disease. At last follow-up, persistent structural disease and distant metastases were more common in sMTC. The differences in clinical presentation and long-term outcomes likely reflect a variable path to MTC diagnosis. In conclusion, sMTC in pts ≤ age 21 y. presents at an older age with more advanced disease, frequently has an actionable driver mutation, and may be more common than previously thought.

Recontacting Patients with Updated Genetic Testing Recommendations for Medullary Thyroid Carcinoma and Pheochromocytoma or Paraganglioma

BACKGROUND

No guidelines exist regarding physicians' duty to inform former patients about novel genetic tests that may be medically beneficial. Research on the feasibility and efficacy of disseminating information and patient opinions on this topic is limited.

METHODS

Adult patients treated at our institution from 1950 to 2010 for medullary thyroid cancer, pheochromocytoma, or paraganglioma were included if their history suggested being at-risk for a hereditary syndrome but genetic risk assessment would be incomplete by current standards. A questionnaire assessing behaviors and attitudes was mailed 6 weeks after an information letter describing new genetic tests, benefits, and risks was mailed.

RESULTS

Ninety-seven of 312 (31.1%) eligible patients with an identified mailing address returned the questionnaire. After receiving the letter, 29.2% patients discussed genetic testing with their doctor, 39.3% considered pursuing genetic testing, and 8.5% underwent testing. Nearly all respondents (97%) indicated that physicians should inform patients about new developments that may improve their or their family's health, and 71% thought patients shared this responsibility. Most patients understood the letter (84%) and were pleased it was sent (84%), although 11% found it upsetting.

CONCLUSIONS

Patients believe it is important for physicians to inform them of potentially beneficial developments in genetic testing. However, physician-initiated letters to introduce new information appear inadequate alone in motivating patients to seek additional genetic counseling and testing. Further research is needed regarding optimal methods to notify former patients about new genetic tests and corresponding clinical and ethical implications.

A Homozygous RET K666N Genotype With an MEN2A Phenotype

CONTEXT

Germline RET K666N mutation has been described as a pathogenic mutation with low disease penetrance for medullary thyroid cancer (MTC) without other features of multiple endocrine neoplasia type 2A. We describe a patient with homozygous RET K666N mutation with MTC and bilateral pheochromocytoma (PHEO).

CASE DESCRIPTION

A 59-year-old woman received a diagnosis of MTC after biopsy of two thyroid nodules. Coincident biochemical and radiologic testing was suspicious for bilateral PHEO, confirmed after bilateral adrenalectomy. There was no evidence of primary hyperparathyroidism (PHPT). She had a total thyroidectomy with neck dissection revealing bilateral MTC with lymph node metastases. Germline RET testing identified homozygous K666N mutations. Genetic testing of family members showed that both adult children harbor a heterozygous K666N mutation. Her 32-year-old son had an elevated calcitonin level and underwent thyroidectomy, which identified MTC. Her 30-year-old daughter had a normal calcitonin level. Prophylactic thyroidectomy showed C-cell hyperplasia only. Three of seven other family members were tested and found to carry the mutation. All had normal calcitonin levels, and none had biochemical evidence of PHEO or PHPT. Given the absence of PHEO in reported RET K666N families, our proband underwent genetic testing for causes of hereditary paragangliomas or PHEO. No additional mutations were identified.

CONCLUSIONS

Here we report a case of a homozygous RET K666N mutation leading to coincident MTC and PHEO. Heterozygous presentations of RET K666N mutations have low penetrance for isolated MTC. We believe that the gene dosage associated with the homozygosity of this variant contributed to the occurrence of bilateral PHEO.

Medullary Thyroid Carcinoma in MEN2A: ATA Moderate- or High-Risk RET Mutations Do Not Predict Disease Aggressiveness

CONTEXT

High-risk RET mutations (codon 634) are associated with earlier development of medullary thyroid carcinoma (MTC) and presumed increased aggressiveness compared with moderate-risk RET mutations.

OBJECTIVE

To determine whether high-risk RET mutations are more aggressive.

DESIGN

Retrospective cohort study using institutional multiple endocrine neoplasia type 2 registry.

SETTING

Tertiary cancer care center.

PATIENTS

Patients with MTC and moderate- or high-risk germline RET mutation.

INTERVENTION

None (observational study).

MAIN OUTCOME MEASURES

Proxies for aggressiveness were overall survival (OS) and time to distant metastatic disease (DMD).

RESULTS

A total of 127 moderate-risk and 135 high-risk patients were included (n = 262). Median age at diagnosis was 42.3 years (range, 6.4 to 86.4 years; mean, 41.6 years) for moderate-risk mutations and 23.0 years (range, 3.7 to 66.8 years; mean, 25.6 years) for high-risk mutations (P < 0.0001). Moderate-risk patients had more T3/T4 tumors at diagnosis (P = 0.03), but there was no significant difference for N or M stage and no significant difference in OS (P = 0.40). From multivariable analysis for OS, increasing age [hazard ratio (HR), 1.05/y; 95% confidence interval (CI), 1.03 to 1.08], T3/T4 tumor (HR, 2.73; 95% CI, 1.22 to 6.11), and M1 status at diagnosis (HR, 3.93; 95% CI, 1.61 to 9.59) were significantly associated with worse OS but high-risk mutation was not (P = 0.40). No significant difference was observed for development of DMD (P = 0.33). From multivariable analysis for DMD, only N1 status at diagnosis was significant (HR, 2.10; 95% CI, 1.03 to 4.27).

CONCLUSIONS

Patients with high- and moderate-risk RET mutations had similar OS and development of DMD after MTC diagnosis and therefore similarly aggressive clinical courses. High-risk connotes increased disease aggressiveness; thus, future guidelines should consider RET mutation classification by disease onset (early vs late) rather than by risk (high vs moderate).

Genetics of Multiple Endocrine Neoplasia Type 1/Multiple Endocrine Neoplasia Type 2 Syndromes

Multiple endocrine neoplasia syndromes types 1 and 2 represent well-characterized yet clinically heterogeneous hereditary conditions for which diagnostic and management recommendations exist; genetic testing for these inherited endocrinopathies is included in these guidelines and is an important part of identifying affected patients and their family members. Understanding of these mature syndromes is challenged as more individuals undergo genetic testing and genetic data are amassed, with the potential to create clinical conundrums that may have an impact on individualized approaches to management and counseling. Clinicians who diagnose and treat patients with MEN syndromes should be aware of these possibilities.

Medullary Thyroid Carcinoma Associated with Germline RETK666N Mutation

BACKGROUND

Multiple endocrine neoplasia type 2 is an autosomal dominant inherited syndrome caused by activating mutations in the RET proto-oncogene. The RET^K666N DNA variant was previously reported in two isolated medullary thyroid carcinoma (MTC) cases, but no family studies are available, and its oncogenic significance remains unknown.

METHODS

The clinical features, genetic data, and family information of eight index MTC patients with a germline RET^K666N variant were assessed.

RESULTS

Four probands presented with MTC and extensive nodal metastasis, one with biopsy-confirmed distant metastasis. Two additional probands presented with localized disease. However, nodal status was not available. Of the final two probands, one had an incidental 1.5 mm MTC and C-cell hyperplasia uncovered after surgery for papillary thyroid carcinoma, and one had two foci of MTC (largest dimension 2.3 cm) detected after surgery for dysphagia. Genetic screening identified 16 additional family members carrying the K666N variant (aged 5-90 years), 11 of whom have documented evaluation for MTC. Of these, only two were found to have elevated basal serum calcitonin upon screening, and the remaining patients had calcitonin levels within the reference range. One patient who elected to have a thyroidectomy at 70 years of age was confirmed to have MTC. The other subject, 57 years old, elected surveillance. Four prophylactic thyroidectomies were performed, with one case of C-cell hyperplasia at 20 years and three cases that revealed normal pathology at ages 21, 30, and 30 years. None of the K666N DNA variant carriers had evidence of primary hyperparathyroidism or pheochromocytoma.

CONCLUSIONS

From this case series, the largest such experience to date, it is concluded that the RET^K666N variant is likely pathogenic and associated with low penetrance of MTC. However, the findings are insufficient to define its pathogenicity clearly and make firm recommendations for screening and treatment. Given the potential benefit associated with early detection of aberrant C-cell growth, and the noninvasive nature of genetic testing, "at risk" individuals should be screened, and if the K666N variant is identified, they should be managed using a personalized screening approach for detection of MTC.