Differentiated thyroid carcinoma generally confers a favorable prognosis, with reported 5-year disease-free survival rates ranging from 80% to 95%, depending on disease stage and associated risk factors. This retrospective descriptive study was conducted on 83 patients with differentiated thyroid cancer treated at the Thai Nguyen Oncology Center from January 2018 to June 2019. The study aimed to determine the 5-year disease-free survival rate and analyze several influencing factors in this patient group. With a mean follow-up time of 68.5 months (range: 61–77 months), the results showed that the mean disease-free survival time was 72.4 ± 1.3 months (95% CI: 69.8–75.1). At 5 years follow-up, the disease-free survival rate was 86.7%. During the follow-up period, no cases of distant metastasis were observed, while locoregional recurrence accounted for 9.6%. There was a statistically significant difference in disease-free survival associated with regional lymph node status. 5-year DFS rates for the pN0, pN1a, and pN1b groups were 97.4%, 80.6%, and 69.2%, respectively (p = 0.014). 5-years DFS rate of the pT4 group was 33.3%, which was lower than that of the pT3 group (84.4%) (p = 0.001). Therefore, pT4 tumor status and postoperative regional lymph node metastasis (especially lateral cervical lymph node metastasis) are predictive factors for disease recurrence.