[Year:2020] [Month:May-August] [Volume:12] [Number:2] [Pages:6] [Pages No:54 - 59]
Aim and objective: To study the clinicopathological profile, risk factors, and outcomes in distant metastasis from differentiated thyroid cancer in a single institution. Materials and methods: A retrospective review of the medical records of 1,408 consecutive patients diagnosed with differentiated thyroid carcinoma (DTC) and managed at Christian Medical College, Vellore, India from January 2004 to December 2013 was performed. There were 108 patients with distant metastasis among this cohort. Results: We had 1,408 DTC patients treated over 10 years, among them 108 patients had distant metastasis (7.7%). Among 1,408 patients, 1,355 (96.2%) were papillary carcinoma thyroid, 49 (3.5%) were follicular, and 4 (0.3%) were Hürthle cell carcinoma. The mean age was 47.84 + 15.4 years ranging from 13 to 75. Age >45 years constitute 60.2%. Among the 108 distant metastasis patients, 85.2% were papillary, and the remaining 14.8% follicular carcinoma. A significant proportion of patients had T3, T4 disease (63.9%) and nodes involved (50%). On logistic regression analysis, the adjusted odds ratio (OR) for detection of metastasis in this series was significantly high for age >45, male gender, follicular cancer or follicular variant papillary thyroid carcinoma (PTC), higher stage T3/T4 primary, and the presence of nodal disease. Of the 108 patients, 64.8% presented with metastases. Among the patients presented with metastatic symptoms, 9.3% had paraparesis or paraplegia. Isolated bone (40.7%) is the commonest site of involvement followed by isolated lung (32.4%) and multiple organ pattern of involvement is the least common (6.5%). All patients with metastatic follicular carcinoma had bony metastasis either alone (81.3%) or rarely with lung (18.7%). The whole-body iodine scan showed positive uptake in 85.7% metastatic patients and was negative in 14.3%. Metastases involving only bone was significantly associated with radioactive iodine avidity. Among the patients who underwent radioiodine therapy, 78.5% have shown a good response to iodine therapy. Patients with age 45 years or patients with bone-only or multiple distant metastatic sites. Metastasectomy was done in 13 patients, curative surgery in 7 and palliative in 6. Conclusion: The prevalence of distant metastasis among our series of DTC is 7.7% with a higher proportion from follicular carcinoma. Significant numbers of patients have distant metastases during the initial evaluation of the primary and it can have a quite morbid presentation like paraparesis and paraplegia in some patients. Bone is the most preferred site of metastases, which requires more studies to evaluate the cause especially in an iodine-deficient country like India. It is possible to treat distant metastases effectively with radioactive iodine therapy as considerable responses are present in most of the patients. Improved efficacy of radioiodine therapy is present in younger patients and for lung metastases. Metastasectomy especially for solitary skeletal metastases is a considerable option. Clinical significance: The pattern of disease in India—the iodine deficiency soil, is different compared to other parts of the world. With the possibility to treat with radioiodine and surgery, extended survival is a possibility in metastatic thyroid disease. When the majority of patients with metastases are diagnosed at presentation, sometimes even presenting with paraplegia, public awareness should be raised to avoid neglecting the thyroid illness.