The size of SDHB-related pheochromocytoma and paraganglioma as an independent predictor of metastatic behavior

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 37-82-Pheochromocytoma & Paraganglioma
Clinical
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-57
Jan Schovanek*1, Victoria L Martucci1, Tito Fojo2, Robert Wesley3, Jaydira Del Rivero1, Thanh Huynh1, Karen T Adams1, Zdenek Frysak4 and Karel Pacak5
1Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 2National Cancer Institute, National Institutes of Health, Bethesda, MD, 3NIH, Bethesda, MD, 4University Hospital, Olomouc, Czech Republic, 5National Institutes of Health (NIH), Bethesda, MD
Background: SDHB mutations are known to be associated with more aggressive behavior in paraganglioma (PGL) and pheochromocytoma (PHEO) commonly resulting in metastatic disease with a fatal outcome. However, at present it is unclear why SDHB and not other hereditary PHEOs/PGLs are so aggressive, especially when compared to those with von Hippel-Lindau gene mutations. Recent studies found that SDHB-related PHEOs/PGLs are often larger, extra-adrenal, and contain lower catecholamines concentrations than other hereditary PHEOs/PGLs. The present study examined whether the size of the SDHB-related primary PHEOs/PGLs is an independent predictor of their metastatic potential. 

Purpose: In the present study we included 106 patients with SDHB-related PHEOs/PGLs in order to evaluate relationship in between the size of the primary tumor, patient survival and tumor metastatic potential taking into account SDHB specific mutation type.

Methods: In this retrospective study we determined the largest diameter of the primary tumor in 106 patients with SDHB mutations and analyzed this data in the context of their size, survival time, type of tumor, time to metastasis and hazard ratio.

Results: Our survival curves indicated that the patients with primary tumors 5.5 cm or larger have a worse overall survival (P=0.0028), with a 5-year survival probability 

of 86.7% compared to 96.2% for patients diagnosed with tumors smaller then 5.5 cm. Although patients with tumors 4.5 cm or larger only have synchronous metastases at a slightly higher rate (29.6% vs 20.0%, P=0.35), overall they develop metastases much faster (P=0.0025) than patients with tumors smaller than 4.5 cm.

Conclusion: Size of the primary tumor has been confirmed to be an important predictor of metastatic potential and survival rate, independently of the specific SDHB mutation and sex of the patient. This should be projected into the clinical practice as recommendation for implementing the latest imaging technologies and guidelines.

Nothing to Disclose: JS, VLM, TF, RW, JD, TH, KTA, ZF, KP

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: This work was supported by intramural research funding of the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health.