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Metastatic pheochromocytoma, paraganglioma occur equally in sporadic, SDHx mutations
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The frequency of metastatic tumors from primary apparently sporadic tumors (AST) appears to increase with age, with a decreased metastatic interval observed compared with succinate dehydrogenase (SDHx) tumors, according to researchers.
“We didn’t find any major differences in the frequency of SDHx vs. AST in adult patients with metastatic disease, suggesting that other genetic and epigenetic factors besides SDHx mutations play an important role in the pathogenesis of metastatic pheochromocytomas and paragangliomas,” Tamara Prodanov, MD, of the National Institutes of Health, Bethesda, Maryland, told Endocrine Today. “In contrast, in children, there were five times more patients with SDHx mutations than with AST, with 75% vs 18%, respectively.”
Tamara Prodanov
Prodanov, with Karel Pacak, MD, PhD, and colleagues retrospectively analyzed 142 patients (82 men, 58% and 60 women, 42%) with metastatic pheochromocytomas and paragangliomas seen from 2000 to 2013, of whom 35 (25%) have died.
Mutations were most common in succinate dehydrogenase complex, subunit B (SDHB) (73 patients, 51%), followed by succinate dehydrogenase complex, subunit D (SDHD) (six patients, 4%), ret proto-oncogene (RET) (three patients, 2%) and von Hippel-Lindau (VHL) (one patient, 1%). AST were seen in 59 patients (42%).
Patients with SDHx mutations (SDHB/SDHD) were aged 31 ± 16 years, on average, at primary tumor diagnosis compared with 40 ± 15 years in patients with AST (P < .001). The number of patients with AST increased with age at initial diagnosis. The average metastatic interval dropped with increasing age in patients with both SDHx and AST.
Of all primary tumors, only 18% measured less than 4.5 cm. Overall, disease was biochemically silent in 7% of patients.
Among patients with SDHB, 19% had metastatic tumors at first diagnosis vs. 15% of patients with AST. Survival rates at 5 years and 10 years were greater for those with metastatic AST than SDHx (P = .039). Survival was significantly different between children and adults (P = .037); this was mostly attributed to the SDHx patients, who had statistically significant longer survival in children that adults (P = .006).
“Our study supports the establishment of certain recommendations for practicing oncologists and other physicians,” Prodanov said.
“(Clinicians should) carefully examine patients who present with pheochromocytomas and paragangliomas in childhood, including testing all of them for SDHx mutations and following them for many years due to the late development of metastases.”
Increased follow-up frequency is important in older patients and those with tumor sizes over 4.5 cm, with whole-body imaging considered for the latter.
“This is especially important in SDHx patients, where one-fifth of patients present with metastatic disease at the initial diagnosis, mainly in bones,” Prodanov said.
Follow-up visits should preferably be done in a collaborative oncology-endocrinology practice
“(Clinicians can) assure patients that, with appropriate follow up and treatment, the 10-year survival rates are currently 75% or 86% for SDHx and AST types, respectively,” Prodanov said. – by Allegra Tiver
Reference:
Prodanov T. Poster PP12-4. Presented at: The Endocrine Society Annual Meeting; March 5-8, 2015, San Diego.
Disclosure: Prodanov reports no relevant financial disclosures.