High rate of persistent/recurrent disease among patients with differentiated thyroid cancer in Saudi Arabia: factors affecting nonremission.

Background And Objectives: A fairly high number of patients with differentiated thyroid cancer (DTC) in our center had locally advanced disease at presentation and/or persistent disease after standard treatment. Therefore, we conducted a retrospective study to find the rate of successful ablation and remission and the factors affecting these outcomes.

Methods: The study included 100 consecutively treated patients (20 males, 80 females; median age 36 years) diagnosed with DTC. Univariate and multivariate logistic regression was used to evaluate the effect of risk factors on the persistence or recurrence of thyroid cancer. All patients underwent total thyroidectomy and had cervical lymph node dissection when indicated. All patients received sodium iodide I 131 ablation once or twice post surgery. Patients were followed clinically by neck ultrasound, (123)I whole body scan and by thyroglobulin measurements and other diagnostic tests as needed.

Results: Over a median follow-up of 7.6 years (range 7-10 years), ablation occurred in 93%, remission in 50%, disease persisted without remission in 41%, and 9% had recurrence after at least 1 year of remission. Papillary thyroid cancer was found in 76%, the follicular variant in 14%, other variants (tall cell and sclerosing types) in 2%, Hurthle cell carcinoma in 4%, and pure follicular thyroid cancer in 4%. Compared with patients in remission, patients with persistent/recurrent disease were older (mean 41 versus 31 years, P=.003), had higher postoperative thyroglobulin (193 versus 29 ng/mL, P=.04) and more advanced TNM staging (P=.005). Risk factors significant for non-remission were age >40 years (odds ratio 4.1, 95% CI 1.5-10.9 years, P=.003) and TNM stage other than 1 (odds ratio 5.5, 95% CI 1.9-16.3, P=.001). Only TNM Stage 1 was significant for remission in the multivariate analysis.

Conclusion: The low remission rate in our DTC patients is probably due to more advanced disease at time of presentation. Early detection may, therefore, be essential in improving outcome.