Prognosticators of survival in differentiated thyroid carcinoma

Differentiated carcinoma of the thyroid has good prognosis, even in patients presenting in the late stage and with distant metastasis. In India, the incidence of papillary carcinoma and follicular carcinoma are in the ratio of 60∶40. A retrospective study was carried out to determine the impact of patient and tumor factors on survival, and to develop a simple rish group staging system to predict survival in patients with differentiated thyroid carcinomas. Four hundred and seventeen (417) patients undergoing primary treatment at our hospital between 197-1985, were entered to the study. There were 198 follicular carcinomas and 219 papillary carcinomas. Impact of patient and tumor variables were studied by drawing Kaplan Meier curves and comparing them by the Chi Sq Test. Age<=40 years (p=0.00001), tumor size <5cms (p=0.01), extrrathyroidal spread (p=0.001) and distant metastasis (p=0.00001) had significant impact on survival. These finding were true for a subset analysis follicular and papillary carcinomas separately. A Cox Regression Analysis was also performed and this showed the above factors to impact significantly on survival. Basing on the regression analysis we devised a simple risk group system and classified the patients as high and low risk. Low risk group patients had a significant survival advantage. Our findings show that the incidence of follicular carcinoma is significantly high in india (48%) and that 65% of our patients are in the high risk group. Incidence of contralateral lobe disease on completion thyroidectomy is as high as 53%. Hence, a more aggressive treatment policy is warranted and total thyroidectomy is the appropriate treatment of choice in our patients.