im of the work: To evaluate the results of radio-active I-131treatment and the prognostic variables of papillary thyroid carcinoma with desmoplastic reaction after long-term follow-up. Material and
Methods: This retrospective study includes analysis of 272 patients, post-surgery and radio-active I-131treatment of papillary thyroid carcinoma with desmoplastic reaction. Follow up period of twelve years with calculation of ten-year recurrence free and the overall survival together with the analysis of the risk factors. RESULTS: 238 Out of 272 (87.5%), showed complete response to the treatment (CR), while 34 patients (12.5%) did not have complete response. Out of these 34 patient 20 (7.4%) showed partial response (PR), 6 patients (2.2%) showed stationary disease (SD), while 8 patients (2.9%) showed progressive disease (PD). Six patients (2.2%) died during the long follow up period. The overall and the ten-year recurrence free survival was 97.5% and 89.9% respectively, in those patients with CR. Recurrence occurred within 5 years in 83.3% of patients who developed local recurrence. Conclusion: Although desmoplasia is a feature of tumor invasiveness, the prognosis of papillary cancer thyroid with desmoplastic reaction in the present study was excellent with high ten years recurrence free and overall survival. Bad prognostic factors include large tumor size, lymph node involvement, old age, vascular and capsular invasion, extra-thyroidal extension, distant metastasis and high thyroglobulin level.