The Effect of Extent of Surgery on Overall Survival in Patients with Medullary Thyroid Cancer

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 414-428-Thyroid Neoplasia & Case Reports
Clinical
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-421
Nazanene H Esfandiari*, David T Hughes, Huiying Yin, Mousumi Banerjee and Megan R Haymart
University of Michigan, Ann Arbor, MI
Objective: To determine the effect of surgery on overall survival in patients with medullary thyroid cancer (MTC).

Background: The 2009 American Thyroid Association guidelines for MTC recommend total thyroidectomy with central neck dissection in all patients with MTC. However, the relationship between disease severity and extent of resection on overall survival remains unknown.

Methods: We analyzed data from 2968 patients diagnosed with MTC between 1998 - 2005 from the US National Cancer Database. Median follow-up was 6 years. Our goal was to determine the relationship between overall survival and number of cervical lymph nodes metastases, tumor size, distant metastases and extent of surgery in patients with MTC. Univariate analyses were performed using Kaplan-Meier estimates and log-rank tests. Multivariable analyses controlling for patient and tumor characteristics were performed using Cox proportional hazards regression. Within disease strata we evaluated the effect of no surgery versus lobectomy, total thyroidectomy, and total thyroidectomy with resection of regional lymph nodes on overall survival.

Results: Older patient age [adjusted hazard ratio + 95% confidence interval = 5.69 (3.34-9.72)], larger tumor size [2.89 (2.14-3.90)], presence of distant metastases [5.68 (4.61-6.99)], and number of positive regional lymph nodes [>16 lymph nodes 3.40 (2.41-4.79)] were independently associated with decreased survival. Overall survival for patients with no cervical lymph node metastases, 1-5, 6-10, 11-16 and ≥ 16 cervical lymph nodes metastases was 90%, 74%, 61%, 69% and 55% respectively. Overall survival for patients with distant metastases was 22%.  When we evaluated the effect of surgical treatment, there was no significant difference in survival based on surgical intervention in patients with tumor size ≤ 2 cm and no distant metastases. However, in patients with tumor size ≥ 2.1 cm and no distant metastases, all surgical treatments resulted in a significant improvement in survival compared to no surgery (P< 0.001) and for patients with distant metastases, only total thyroidectomy with regional lymph node resection resulted in a significant improvement in survival (P<0.001) with 30% surviving versus 15% who underwent no surgical intervention.

Conclusion: The number of lymph node metastases correlates with overall survival. Based on our data, extent of surgery in patients with MTC should be tailored to tumor size and presence of distant metastases.

Nothing to Disclose: NHE, DTH, HY, MB, MRH

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: K award 1K07-CA-154595-02