Role of Surgery in the Multimodal Treatment of Pituitary Carcinoma: A Retrospective Single-Institution Case Series

Introduction: Pituitary carcinoma (PC) is a rare, aggressive endocrine neoplasm characterized by metastasis and challenging clinical management. The transformation from pituitary adenoma (PA) to PC is poorly understood, and predictors of metastasis remain elusive. This study evaluates the clinical course, surgical outcomes, and molecular characteristics of PC. Methods: We retrospectively reviewed patients with PC treated at the M. D. Anderson Cancer Center between 1993 and 2023. Primary outcomes included metastasis-free survival and overall survival (OS). Clinical features, radiographic findings, surgical strategies and outcomes, immunohistochemical profiles, and MIB-1 were analyzed. Results: The cohort (n = 20) had a median age at PA and PC diagnosis of 33.9 and 43.3 years, respectively. The median metastasis-free interval was 7.4 years. GH- and ACTH-secreting tumors showed shorter times to PC diagnosis, while nonfunctioning PAs had longer metastasis-free survival. PAs with MIB-1 > 10% had shorter survival. Dura was the most common site of metastasis within the CNS, and bone was the most common outside the CNS. Leptomeningeal disease was seen in six patients. PAs became aggressive > five years after initial surgical resection (n = 13) or metastasized early within the first five years (n = 7). Median OS from PA diagnosis was 13.7 years, and 8.6 years from PC diagnosis. A total of 102 neurosurgical procedures were performed, with a median of five per patient; the median was similar in patients surviving longer than five years vs. those whose survival was shorter (5.0 vs. 4.5 procedures, p = 0.661). Most surgical interventions post-PC diagnosis were for optic decompression or metastasectomy. All long-term survivors (at least five years after PC diagnosis) received temozolomide-based therapy, with most also receiving radiotherapy. Conclusions: PC shows a variable clinical course, with some PAs progressing to PC after years, while others transform rapidly. All long-term survivors received temozolomide-based therapy, most in combination with radiotherapy and repeated surgical intervention, suggesting that aggressive multimodal management may be associated with prolonged survival. Future research will focus on identifying reliable predictors of metastasis at different time points in the complex clinical evolution of these tumors.