Gains Realized in Pituitary Carcinoma Survival: A Contemporary Evaluation Using the Seer Database

Background: Pituitary carcinomas are rare tumors accounting for 0.1% of all pituitary tumors. They are defined as having noncontiguous metastases from their primary sellar origin and can be difficult to diagnose due to a lack of histological differentiation. The difficulty of diagnosis can result in delay of critical treatment in these patients, and treatment is best managed by a multidisciplinary team. Treatment delay combined with presence of metastases and complexity of treatment regimens results in poor prognoses for patients. During the last several decades, our understanding of pituitary carcinomas has dramatically increased, and there have been recent initiatives to improve patient access to healthcare, specifically the 2010 Affordable Care Act (ACA). We investigated whether there were any changes in incidence and treatment outcomes of pituitary carcinoma that correlated with these legislative and informational advances.

Methods: The Surveillance, Epidemiology, and End Results Program (SEER) (November 2018 data submission) was used to identify study participants. Patients with primary site pituitary tumors (ICD-0–3 Code C75.1) classified as having malignant behavior and diagnosed between January 1, 1975 and December 31, 2016 were identified. Those patients younger than 18 years of age at the time of diagnosis, without a known age, or exhibiting histology other than adenoma or adenocarcinoma (8,140–8,389) were excluded. Total 175 participants were identified from these parameters. As the SEER malignant classification encompasses both invasive adenomas and carcinomas, additional stratification based on presence of noncontiguous metastases narrowed our analysis to 26 pituitary carcinomas. We sought to examine whether there was an increase in the number of pituitary carcinoma patients since the enactment of the ACA.

Results: Overall survival of pituitary carcinoma patients after 1, 2, and 5 years was 86, 71, and 64%, respectively after controlling for adequate follow-up. Cause-specific survival of these participants was similar with findings of 94, 77, and 68%, respectively. These findings offer a marked improvement in prognosis, with previous studies noting worse survival (20% after 8 years postdiagnosis with 66% mortality within the first year) (Oh [2012], Scheithauer [2005], and Pernicone [1997]). The present study shows greater incidence and better prognosis compared with the most recent SEER data (Hansen [2014]). Furthermore, there has been a 116.7% increase in pituitary carcinoma diagnosis since 2010, coinciding with the ACA.

Conclusion: Pituitary carcinomas in the United States are rare but have shown an increased incidence in the SEER database over time. Given that these are rare, revisiting this diagnosis and its prognosis is important to gain a contemporary perspective. Our data show a marked improvement in prognosis for pituitary carcinoma and significantly increased numbers from prior studies, changing our understanding of this disease. While the exact cause of these trends is unclear, it is most likely due to a combination of many factors. These may include better powered studies, improved diagnostic capability, expanded treatment options, physician awareness, and improved access to healthcare. Our data showing a significant increase in pituitary carcinoma diagnosis since the enactment of the ACA support the inclusion of improved healthcare access as a factor improving patient prognosis.