Endocrine Abstracts

JOINT607

Introduction: Pituitary carcinoma (PC) is defined as the presence of metastasis (craniospinal or systemic) from a pituitary tumor. Given the rarity of PC, limited information regarding survival and factors which may influence survival is available in literature.

Aim: To assess overall survival following detection of metastatic disease in patients with PC and to determine factors associated with clinical outcomes in these patients.

Methods: All patients with PC diagnosed between 1997 and 2024 were identified using the Mayo Data Explorer. Information regarding patient demographics, tumor characteristics, management, and outcomes was extracted.

Results: 25 patients (56% male) were included; mean age at initial pituitary adenoma (PA) diagnosis was 50 ± 11.9 years. PA size at initial diagnosis was 2.1 ±1.3 cm, 18 (72%) of which were functioning tumors. Surgery was the initial treatment in 24 (96%) patients. Radiation therapy (RT) was used in 25 (100%) cases with a median time to RT of 12 months (range 0-239). Median time to metastasis diagnosis was 6 (range 1-32) years, mean age of 59 ±10.6 years. The most common site of metastasis was bone in 13 (52%) patients, followed by central nervous system (CNS) and spine in 12 (48%). Systemic therapy alone (temozolomide, CVD [cyclophosphamide, vincristine, dacarbazine], etoposide/cisplatin, pembrolizumab or lutetium Lu 177 dotatate) was used in 6 (24%) patients, local treatment alone (radiotherapy, cryoablation or metastasectomy) was used in 9 (36%) of patients, combination treatment (locoregional and systemic therapy) in 8 (32%), and no additional treatment in 2 (8%). Median follow-up was 1.7 years (range 0.1-15.5). At last follow-up, 11 (44%) patients were alive, 11 (44%) died of PC, and 3 (12%) died from othercauses. The median survival time of patients from the identification of metastasis was 4 years. The 1-, 5- and 11-year survival rates were 70%, 37% and 13%, respectively. No difference in survival was seen according to metastasis site (CNS vs distant metastasis ), corticotroph vs other PC cell type or treatment before or after 2010. Improved survival correlated with temozolomide (TMZ) treatment (n = 9) compared to those not treated with TMZ (P=0.048) and in nonfunctional compared (n = 7) to functional tumors (P=0.048).

Conclusion: This study demonstrates that survival among patients with PC is higher among those who received temozolomide and if the tumor was nonfunctioning. Despite current treatment modalities 5-year survival was poor (37%). Additionally, there is a lag between PA and PC diagnosis (6 years) emphasizing the importance of long-term follow-up.