Incidence, Recurrence and Mortality Among Filipinos With Differentiated Thyroid Cancer: A Systematic Review.

Background: The majority of thyroid malignancies are differentiated thyroid carcinomas (DTCs). We examined the incidence, disease extent, recurrence and disease-specific mortality (DSM) of DTC among Filipinos residing in the Philippines and Filipino immigrants. Methodology: In accordance with the 2020 PRISMA statement, we performed a systematic literature search in MEDLINE, Google Scholar, EBSCO, Cochrane and Clinicaltrials.gov for the period January 1, 1980 until January 27, 2022. Pooled incidence rate ratio and pooled proportions of disease extent, recurrence and DSM were determined. Results: Literature search yielded 1,852 studies. Out of 26 articles retrieved, nine retrospective case controls and cohorts were included. Incidence of DTC was significantly higher in female Filipino immigrants compared with non-Hispanic whites (NHW). Distant metastases and recurrence were more common among Filipinos and Filipino immigrants compared with NHW. Limited data showed higher DSM in Filipino immigrants and NHW than Filipinos, which may be influenced by reporting bias. Conclusions: This review supports the trend of increased incidence and recurrence of DTC among Filipinos, although case registries are essential to confirm these findings. In the setting of the newly released Philippine guidelines for DTC, prospective studies with active long-term follow-up will help detect any changes in the outcomes of DTC among Filipinos.