Author

Eric Kuo

Date of Award

January 2014

Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Ronald R. Salem

Subject Area(s)

Medicine

Abstract

The increasing utilization of imaging technology has led to the diagnosis of cancers earlier in their clinical course. When small tumor size is coupled with relatively indolent histology, excellent oncologic outcomes require the risks of surgery to be carefully considered. However, characteristics and outcomes of small cancers of the thyroid and endocrine pancreas remain poorly defined, and evidence to guide their management is sparse.

Patients with tall cell (mTCV) and diffuse sclerosing (mDSV) variants of papillary thyroid microcarcinoma (mPTC), follicular (mFTC) and Hurthle cell microcarcinoma (mHCC), parathyroid carcinoma (PC) and pancreatic neuroendocrine tumors (PNETs) ≤ 2 cm in size were selected from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database, 1988-2009. Data regarding incidence, characteristics, and outcomes were extracted and analyzed with χ2 tests, ANOVA, the Kaplan Meier method, log-rank tests, and Cox proportional hazards.

97 mTCV, 90 mDSV, 371 mFTC, 193 mHCC, and 263 PNETs ≤ 2 cm were identified. The incidence of mTCV, mDSV, and mFTC remained stable throughout the study period, while the incidences of mHCC and PNETs ≤ 2 cm increased by 400% and 710% over the study period, respectively. Although survival was similar, mTCV and mDSV were associated with higher rates of extrathyroidal extension and nodal metastasis in comparison to classic mPTC. mFHCC had over eight times the rate of distant metastases compared to mPTC and was associated with compromised 10-year disease specific survival (95.4 vs. 99.3%, P<0.001). Rates of extrapancreatic extension, nodal metastasis, and distant metastasis in PNETs ≤ 2 cm were 17.9%, 27.3%, and 9.1%, respectively.

The incidence of many endocrine cancers is increasing, presumably due to increased detection. All histologies studied were capable of exhibiting aggressive behavior despite small tumor size. Further studies that specifically examine the risks and benefits of surgical therapy in small tumors may clarify future surgical decision making.

Comments

This is an Open Access Thesis.

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