Objectives/hypothesis: Evaluate the impact of medical and surgical interventions on the survival of patients with papillary microcarcinoma (PMC) of the thyroid, a common tumor with an increasing worldwide incidence.
Study design: Cross-sectional population analysis of a prospectively maintained database.
Methods: Cases of nonmetastatic PMC treated with cancer-directed surgery with or without postoperative radioactive iodine (RAI) therapy were extracted from the Surveillance, Epidemiology and End Results Database (1988-2005). Kaplan-Meier disease-specific survival (DSS) and overall survivals were compared according to extent of thyroidectomy and use of RAI therapy. Cox regression analysis was performed to determine the influence of these factors on survival.
Results: A total of 7,818 cases of PMC were identified. Overall actuarial survival rates at 10 and 15 years were 96.6% and 96.3%, respectively. DSS was 99.9% at both time intervals, with a total of 10 thyroid cancer-related deaths. There were no significant differences in DSS for patients who underwent total thyroidectomy, near-total/subtotal thyroidectomy, or lobectomy (P = .239). DSS for patients receiving RAI therapy was not significantly different than that of patients who did not (P = .504). On multivariate analysis, only increasing age at diagnosis, successfully predicted poor DSS (P = .001), whereas gender (P = .481), use of RAI therapy (P = .633), and extent of thyroidectomy (P = .104) did not.
Conclusions: PMC carries an excellent prognosis with respect to both overall and disease-specific survival that is independent of surgical extent and the use of RAI therapy. An isolated, fine-needle-aspiration proven unilateral PMC focus in a patient lacking evidence of metastatic disease may be treated with lobectomy alone.