Abstract
BACKGROUND: The prognosis for differentiated thyroid cancer of follicular origin (DTC) is generally good, with survival rates comparable to those of the general population for some patients. However, overall survival is influenced by many factors. Our study aims to analyze five-year and ten-year overall survival rates in follicular differentiated thyroid cancer and the independent factors influencing it in Moroccan patients. METHODS: This retrospective cohort study included all patients with differentiated thyroid cancer referred to the nuclear medicine department at Ibn Rochd Hospital between 2004 and 2012. Using the Kaplan-Meier method, we calculated overall survival, five-year survival, and ten-year survival rates. We compared overall survival according to several factors using the log-rank test. RESULTS: A total of 1366 patients were included in the study, distributed as follows: 89.6% were female, and 10.4% were male, with a sex ratio of 8.5. The mean age at diagnosis was 44 years, with extremes ranging from 14 to 85 years. The mean overall survival was 26.074 years [25.51; 26.63 years]. The five-year survival rate was 94%, and the ten-year survival rate was 91%. Male gender, age over 55 years, follicular histological type, tumor size >4 cm, ETE and vascular invasion, postoperative Tg level and post-RAI therapy >10 ng/ml, presence of lymph node invasion, and distant metastases are factors that reduce survival rates in patients with DTC. Additionally, advanced-stage and high-risk groups are associated with lower overall survival rates (p <0.001). CONCLUSION: Overall survival rates in Moroccan patients with DTC are equivalent to those described in the literature. It is also significantly influenced by age, gender, histological type, vascular invasion, extra-thyroidal extension, postoperative Tg level, post-RAI therapy, the presence of lymph node invasion and distant metastases, as well as disease stage and risk group, as widely reported in the literature.