Abstract 574P
Background
Pheochromocytoma (PCC) and paraganglioma (PGL) are rare tumors occurring in the adrenal medulla and extra-adrenal tissues, respectively. The clinicopathological features have not been fully elucidated, especially in Asian cohorts.
Methods
We retrospectively reviewed 65 patients with PCC/PGL between 1983 and 2020. Patient characteristics and clinical outcomes (overall survival [OS] and relapse-free survival [RFS]) were analyzed based on the medical records. Morphological assessment and immunostaining of Ki-67 and succinate dehydrogenase complex subunit B (SDHB) were performed in the available specimens. Subsequently, the influence of the grading system for pheochromocytoma and paraganglioma (GAPP) score and SDHB negativity on the clinical outcomes was evaluated.
Results
The median age of the patients was 51 years, and PGL accounted for 69% of the cases. Initial stage was localized disease in 83% of the patients, and the major primary lesions were in the adrenal gland (31%), retroperitoneum (24%), and bladder (15%). Fifty-three patients with localized disease underwent curative resection, and six and two patients with metastatic disease underwent surgery and chemotherapy, respectively. Morphologically, the GAPP score was 0-2 (low-risk) in nine, 3-6 (intermediate-risk) in 33, and 7-10 (high-risk) in three specimens. SDHB immunostaining was performed in 41 specimens, and the negativity rate was 19%. The 3-year OS rate in all 65 patients was 95%, and was significantly better in patients with localized than metastatic disease (3-year OS 98% vs. 80%, P = 0.008). The 3-year RFS rate in the 53 patients with localized disease was 87%. The rate was significantly different among patients in the low-risk, intermediate-risk, and high-risk groups (3-year rate 100% vs. 96% vs. 33%, P < 0.0001), and between those in the SDHB-positive and SDHB-negative groups (3-year rate 100% vs. 57%, P = 0.03).
Conclusions
While the general outcome of PCC/PGL was favorable, our analysis suggested that high-risk GAPP score and SDHB negativity were predictors of subsequent relapse in patients with localized disease who underwent resection. The correlation between lack of SDHB expression and SDH-related mutations should be assessed in future studies.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
S. Takahashi: Financial Interests, Personal, Invited Speaker: Daiichi Sankyo; Financial Interests, Personal, Invited Speaker: MSD; Financial Interests, Personal, Invited Speaker: Chugai; Financial Interests, Personal, Advisory Board: Bayer; Financial Interests, Personal, Invited Speaker: Eisai; Financial Interests, Institutional, Principal Investigator: Taiho; Financial Interests, Institutional, Principal Investigator: Daiichi Sankyo; Financial Interests, Institutional, Principal Investigator: Novartis; Financial Interests, Institutional, Principal Investigator: Ono Pharmaceutical; Financial Interests, Institutional, Principal Investigator: Eisai; Financial Interests, Institutional, Principal Investigator: IQVIA; Financial Interests, Institutional, Principal Investigator: Bristol Myers Squib; Financial Interests, Institutional, Principal Investigator: Bayer; Financial Interests, Institutional, Principal Investigator: AstraZeneca. All other authors have declared no conflicts of interest.