Risk Factors for Recurrence in Filipinos with Well-Differentiated Thyroid Cancer

BACKGROUND: The incidence of well-differentiated thyroid cancer (WDTC) has increased in recent years. Despite its excellent prognosis, increasing morbidity from recurrent diseases continues to affect long-term outcomes. Among at-risk populations, Filipinos have the highest incidence of thyroid cancer worldwide, characterized by a highly aggressive and recurrent form of disease. Here, we sought to identify risk factors associated with disease recurrence among Filipinos with WDTC. METHODS: This retrospective cohort study examined 723 patients diagnosed with WDTC seen at Philippine General Hospital. Affected individuals were classified based on the presence or absence of disease recurrence. Multivariate logistic regression analyses were used to determine significant predictors of recurrence. RESULTS: Multiple risk factors, including age >45 years (odds ratio [OR], 1.44), multifocality of cancer (OR, 1.43), nodal involvement (OR, 4.0), and distant metastases at presentation (OR, 2.78), were significantly associated with a recurrence of papillary thyroid cancer (PTC). In contrast, follicular variant histology (OR, 0.60) and postsurgical radioactive iodine therapy (OR, 0.31) were protective for PTC recurrence. Distant metastases at presentation (OR, 19.4) and postsurgical radioactive iodine therapy (OR, 0.41) were associated with follicular thyroid cancer (FTC) recurrence. CONCLUSION: Lymph node metastases at presentation was the strongest predictor of recurrence in PTC, whereas distant metastases at presentation was the strongest for FTC recurrence. Among Filipinos, stratification of WDTC patients based on recurrence risk factors identified in this study will be helpful in guiding the intensity of treatment strategies and long-term thyroid cancer surveillance.