Clinical Outcomes and Prognostic Determinants in Poorly Differentiated Thyroid Cancer: A Surgical Perspective

Poorly differentiated thyroid cancer (PDTC) is an aggressive malignancy with intermediate characteristics between well-differentiated and anaplastic thyroid carcinoma. It remains a significant cause of thyroid cancer mortality despite its rarity. The absence of standardized treatment guidelines and its heterogeneous nature complicate clinical management. This study aims to identify prognostic determinants influencing surgical outcomes in PDTC, specifically disease-free survival(DFS) and overall survival(OS). This retrospective cohort study analyzed PDTC cases treated at a tertiary cancer center in Eastern India between 2013 and 2021. Patients with histologically confirmed PDTC per the Turin/MSKCC criteria who underwent surgical management were included. Demographic, clinical, and histopathological data were collected to evaluate oncological outcomes, including OS and DFS. Kaplan-Meier survival analysis was performed, and Cox proportional hazards regression was utilized to identify independent prognostic factors. The incidence of PDTC among all thyroid cancers was 1.27% (21/1643), with 15 patients (0.9%) undergoing primary surgical treatment. The cohort comprised 53.3% females, with a median age of 48 years. Lymphovascular invasion(LVI) was observed in 53.3%, perineural invasion (PNI) in 13.3%, extrathyroidal extension(ETE) in 26.7%, and distant metastases (DM) in 26.7%. R0 resection was achieved in 86.67% of cases. Kaplan-Meier analysis estimated two-year OS at 78% and five-year OS at 68%. The predictors of OS included LVI (p=0.02), ETE, and PNI, while DFS was impacted by LVI, PNI (HR=9.83, p=0.023), and DM (HR=13.57, p=0.023). Necrosis and mitotic index >3/hpf had weak correlations with survival outcomes. This study highlights the critical prognostic role of LVI, PNI, ETE, and DM in PDTC outcomes and need for more Indian studies. Despite total thyroidectomy and adjuvant therapies, recurrence remains a challenge, necessitating a multidisciplinary approach. Given the absence of standardized treatment protocols, larger multicenter studies with molecular profiling are needed to refine prognostic models and optimize PDTC management.