The Incidence and Survival of Rare Cancers of the Thyroid, Parathyroid, Adrenal, and Pancreas.

PURPOSE: With the exception of papillary and follicular thyroid cancer, malignant cancers of the thyroid, parathyroid, adrenal, and endocrine pancreas are uncommon. These rare malignancies present a challenge to both the clinician and patient, because few data exist on their incidence or survival. We analyzed the incidence and survival of these rare endocrine cancers (RECs), as well as the trends in incidence over time.

METHODS: We used the NCI's SEER 18 database (2000-2012) to investigate incidence and survival of rare cancers of the thyroid, parathyroid, adrenal, and endocrine pancreas. Cancers were categorized using the WHO classification systems. We collected data on incidence, gender, stage, size, and survival. Time trends were evaluated from 2000-2002 to 2010-2012.

RESULTS: We identified 36 types of rare cancers in the endocrine organs captured in the SEER database. RECs of the thyroid had the highest combined incidence rate (IR8.26), followed by pancreas (IR 3.24), adrenal (IR 2.71), and parathyroid (IR 0.41). The incidence rate for all rare endocrine organs combined increased 32.4 % during the study period. The majority of the increase was attributable to rare cancers of thyroid, which increased in not only microcarcinomas, but in all sizes. The mean 5-year survival for RECs is 59.56 % (range 2.49–100 %).

CONCLUSIONS: This study is a comprehensive analysis ofthe incidence and survival for rare malignant endocrine cancers. There has been an increase in incidence rate of almost all RECs and their survival is low. We hope that our data will serve as a source of information for clinicians as well as bring awareness regarding these uncommon cancers.