Temozolomide is the main chemotherapy drug used for aggressive pituitary tumors and pituitary carcinomas that do not respond to standard treatments like surgery or radiation. Most of what is known about how well this treatment works comes from small studies in Europe and the United States, with very little data from Latin America. Building on a previous multicenter study conducted in Brazil, this study (TEMPLA) expands data collection to additional centers across Latin America to better understand how patients in this region respond to temozolomide, how long the treatment controls the tumor, and whether certain tumor characteristics (such as MGMT status) can help predict which patients are more likely to benefit.

Temozolomide is the first-line chemotherapeutic agent recommended for aggressive pituitary neuroendocrine tumors (PitNETs) and pituitary carcinomas refractory to standard therapy, including surgery and radiotherapy. Current evidence supporting its use derives largely from small case series and single-country cohorts, with limited data representative of Latin American populations.

TEMPLA (TEMozolomide in Pituitary tumors - Latin America) is a retrospective, multicenter cohort study that expands a previously conducted national Brazilian cohort on temozolomide use in aggressive PitNETs and pituitary carcinomas to a broader Latin American regional scope. Participating centers will retrospectively identify patients treated with temozolomide for histologically confirmed aggressive PitNET (defined by Knosp grade ≥3, radiological growth >20% within 6 months, and/or progression despite optimized standard therapy) or histologically/clinically confirmed pituitary carcinoma.

Data will be collected via a standardized electronic case report form (REDCap), with harmonized diagnostic and response criteria applied across all participating sites to minimize inter-center heterogeneity. Mandatory variables include tumor subtype and lineage, temozolomide dose and treatment duration, and radiological response assessed from pre- and post-treatment imaging. MGMT status (by immunohistochemistry and/or promoter methylation analysis, where locally available) will be collected as a secondary variable and analyzed as an exploratory predictor of treatment response.

The primary aim of this study is to characterize the radiological response rate to temozolomide across Latin American centers. Secondary aims include estimating progression-free survival and overall survival following temozolomide initiation, evaluating the association between MGMT status and treatment response, and describing treatment-related adverse events.

Inclusion Criteria:

Histologically confirmed pituitary neuroendocrine tumor (PitNET) meeting criteria for aggressive behavior (Knosp grade ≥3, radiological tumor growth >20% within 6 months, and/or progression despite optimized standard therapy including surgery and/or radiotherapy), OR histologically or clinically confirmed pituitary carcinoma (defined by the presence of craniospinal or systemic metastasis) Treatment with temozolomide, at any dose or duration, administered for the above indication Availability of pre-treatment and post-treatment imaging sufficient to assess radiological response Temozolomide treatment initiated within the defined study period

Exclusion Criteria:

Insufficient clinical or imaging data to assess the primary outcome measure Temozolomide administered for an indication other than aggressive PitNET or pituitary carcinoma Loss to follow-up before any post-treatment imaging assessment

The study population consists of patients diagnosed with aggressive pituitary neuroendocrine tumors (PitNETs) or pituitary carcinomas who were treated with temozolomide as part of routine clinical management at participating centers across Latin America, including a previously established Brazilian multicenter cohort. Patients were identified retrospectively through review of institutional pathology, oncology, and endocrinology records. The population reflects real-world clinical practice, encompassing diverse tumor subtypes (functioning and non-functioning PitNETs) and variable temozolomide dosing protocols, rather than a population selected under a standardized experimental treatment regimen.