Positive Impact of Genetic Test on the Management and Outcome of Patients With Paraganglioma and/or Pheochromocytoma

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. To characterize the survival of BRCA carriers with EOC compared with noncarriers and to determine whether BRCA1 and BRCA2 carriers show similar survival patterns. 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). Five-year overall mortality. 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). 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.

The group of susceptibility genes for pheochromocytoma that included the proto-oncogene RET (associated with multiple endocrine neoplasia type 2 [MEN-2]) and the tumor-suppressor gene VHL (associated with von Hippel-Lindau disease) now also encompasses the newly identified genes for succinate dehydrogenase subunit D (SDHD) and succinate dehydrogenase subunit B (SDHB), which predispose carriers to pheochromocytomas and glomus tumors. We used molecular tools to classify a large cohort of patients with pheochromocytoma with respect to the presence or absence of mutations of one of these four genes and to investigate the relevance of genetic analyses to clinical practice. Peripheral blood from unrelated, consenting registry patients with pheochromocytoma was tested for mutations of RET, VHL, SDHD, and SDHB. Clinical data at first presentation and follow-up were evaluated. Among 271 patients who presented with nonsyndromic pheochromocytoma and without a family history of the disease, 66 (24 percent) were found to have mutations (mean age, 25 years; 32 men and 34 women). Of these 66, 30 had mutations of VHL, 13 of RET, 11 of SDHD, and 12 of SDHB. Younger age, multifocal tumors, and extraadrenal tumors were significantly associated with the presence of a mutation. However, among the 66 patients who were positive for mutations, only 21 had multifocal pheochromocytoma. Twenty-three (35 percent) presented after the age of 30 years, and 17 (8 percent) after the age of 40. Sixty-one (92 percent) of the patients with mutations were identified solely by molecular testing of VHL, RET, SDHD, and SDHB; these patients had no associated signs and symptoms at presentation. Almost one fourth of patients with apparently sporadic pheochromocytoma may be carriers of mutations; routine analysis for mutations of RET, VHL, SDHD, and SDHB is indicated to identify pheochromocytoma-associated syndromes that would otherwise be missed.

To assess the yield and the clinical value of systematic screening of susceptibility genes for patients with pheochromocytoma (pheo) or functional paraganglioma (pgl). We studied 314 patients with a pheo or a functional pgl, including 56 patients having a family history and/or a syndromic presentation and 258 patients having an apparently sporadic presentation. Clinical data and blood samples were collected, and all five major pheo-pgl susceptibility genes (RET, VHL, SDHB, SDHD, and SDHC) were screened. Neurofibromatosis type 1 was diagnosed from phenotypic criteria. We have identified 86 patients (27.4%) with a hereditary tumor. Among the 56 patients with a family/syndromic presentation, 13 have had neurofibromatosis type 1, and germline mutations on the VHL, RET, SDHD, and SDHB genes were present in 16, 15, nine, and three patients, respectively. Among the 258 patients with an apparently sporadic presentation, 30 (11.6%) had a germline mutation (18 patients on SDHB, nine patients on VHL, two patients on SDHD, and one patient on RET). Mutation carriers were younger and more frequently had bilateral or extra-adrenal tumors. In patients with an SDHB mutation, the tumors were larger, more frequently extra-adrenal, and malignant. Genetic testing oriented by family/sporadic presentation should be proposed to all patients with pheo or functional pgl. We suggest an algorithm that would allow the confirmation of suspected inherited disease as well as the diagnosis of unexpected inherited disease.