Outcomes of systemic treatment in patients with metastatic pheochromocytoma and paraganglioma: A single center retrospective analysis.

Abstract

2 Background: Pheochromocytomas and paragangliomas (PPGLs) are neuroendocrine tumors arising from chromaffin cells of the adrenal medulla or extra-adrenal paraganglia. Although 15-17% of patients develop metastatic disease, there are very limited systemic treatment options. In this study, we aimed to evaluate the treatment landscape and outcome in PPGL patients retrospectively. Methods: Between December 2004 and December 2021, 33 patients were diagnosed with metastatic PPGLs and received systemic treatment at the Department of Oncology, Asan Medical Center, Seoul, South Korea. Metastatic PPGLs included a locally advanced unresectable disease, initially metastatic disease, and recurrent disease. Systemic treatment involves cytotoxic chemotherapy and targeted agents, and efficacy analysis included the objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). Results: The median age at diagnosis was 49 years (range, 15–74), 17 patients were male (52%), and 22 patients were pheochromocytomas (67%). Disease status was recurrent (73%), initially metastatic (21%), and locally advanced (6%). Of 23 patients who underwent germline tests, 14 (61%) were identified with germline mutations, and the most frequent mutation was SDHB germline mutation (n=8, 57%). Of the 33 patients, 18 received chemotherapy with cyclophosphamide, vincristine, and dacarbazine (CVD). The ORR was 22% (4/18; all PR), and the disease control rate (DCR) was 67% (n=12). The median PFS was 7.9 months [95% confidence interval (CI), 1.6-not available (NA)], and the median OS was 36.2 months (95% CI, 5.7-NA). Six patients were treated with sunitinib, and the ORR was 33% (2/6; all PR), and the DCR was 83% (n=5). The median PFS was 14.6 months (95% CI, 3.6-NA), and the median OS was 14.6 months (95% CI, 3.6-NA). In CVD treatment, patients with SDHB/SDHD mutation (either germline or somatic) were significantly associated with superior OS & PFS compared with the non-SDHB/SDHD mutation group, with a median OS of 94.0 months vs. 5.7 months (P = 0.01) and a median PFS of 20.1 months vs. 1.6 months (P = 0.03), respectively. In the SDHB/SDHD mutation group, the ORR was 50% (3/6, all PR), and the DCR was 100% (n=6), but in a non-SDHB/SDHD mutation group, the ORR was 11% (1/9, PR) and the DCR was 44% (n=4). Conclusions: Systemic treatment with CVD and sunitinib provided meaningful disease control, and outcomes were comparable with previous data. Especially, CVD treatment was effective in patients with SDHB/SDHD mutation, and further validation is needed in future studies.