Tumor risks and surveillance outcomes in SDHA variant carriers.

OBJECTIVE: SDHA germline pathogenic variants confer a lower paraganglioma risk compared with other hereditary paraganglioma genes. Reduced screening for carriers without a personal or family history of SDHA-associated tumors has been proposed; however, supporting data remain limited. This single-institution cohort study addresses this by characterizing SDHA carrier tumor features and long-term screening outcomes. DESIGN: This is a retrospective cohort study with longitudinal surveillance follow-up. METHODS: Clinical records of patients with an SDHA likely pathogenic or pathogenic germline variant identified between July 2015 and July 2025 in the Family Cancer Assessment Clinic at the University of Utah Huntsman Cancer Institute were reviewed. RESULTS: Among 106 SDHA carriers, 15% had a personal history of an SDHA-associated tumor. Of identified tumors, 47% were metastatic or demonstrated malignant behavior (3/3 extra-adrenal PPGLs, 4/5 GISTs, 0/7 head/neck PPGLs). No affected carriers had known family history of SDHA-associated tumors, and no cases of multiple related tumors were observed. Most carriers (63%) lacked a personal or family history of SDHA-associated tumors. Over 10 years of high-risk screening, zero previously unidentified SDHA-associated tumors were found. CONCLUSION: Our findings align with prior evidence that SDHA variants confer a lower tumor risk than other hereditary PPGL genes, lending support to an SDHA-specific screening approach. However, higher rates of malignant tumor behavior in affected carriers compared with sporadic disease suggest SDHA variants may be impactful in contexts like treatment decision-making. These contrasts highlight that while modifying or forgoing tumor screening may be reasonable for many carriers, a nuanced clinical approach remains essential for this population.