THE INFLUENCE OF DIAGNOSTIC PROCEDURES ON THE MOST SUCCESSFUL SURGICAL-MANAGEMENT OF THYROID-DISEASES

Objective: To determine the value of different diagnostic procedures i n obtaining the most accurate pathomorphologic diagnosis in order to h elp the surgeon perform the most appropriate extent of thyroid resecti on. Design: A retrospective study of 586 patients who underwent thyroi d resection in a 10 year period from January 1, 1983 to December 31, 1 993. The value of a particular diagnostic procedure for the correct de cision was evaluated by comparison of groups of patients using chi-squ are chi(2) (p = 0.05). The value of fine needle aspiration cytology (F NAC) for correct diagnosis was evaluated by Galen-Gambino using its se nsitivity, specificity and accuracy. Setting: Teaching hospital in Slo vakia. Subjects: Patients with thyroid diseases who presented themselv es to the general surgical unit. Main outcome measures: To determine t he influence of different preoperative diagnostic procedures (clinical investigation, fine needle aspiration cytology, frozen section) on th e surgeon's decision to make and provide the correct extent of resecti on and on the clinical outcome and operative complications. Results: 1 . A comparison of direct influence of three different preoperative dia gnostic procedures on the main outcome showed a significant difference (p < 0.05) in favor of FNAC in choosing the most accurate extent of r esection and in terms of clinical outcome. No significant difference a mong the diagnostic procedures was found in the rate of postoperative complications (p > 0.05). 2. A comparison of two groups of patients wi th or without FNAC as a single diagnostic procedure showed a significa nt difference in terms of the most accurate surgical resection (p < 0. 05) but there was no significant difference in the clinical outcome an d the rate of operative complications (p > 0.05). 3. A significant dif ference allowing a correct extent of resection (p < 0.05) was also pro ved in favor of preoperative FNAC in the group of patients with toxic goiter. 4. A significant difference (p < 0.05) was proved also in the group of patients for whom FNAC specified exactly, also precancerous ( Hurtle and atypical adenoma) compared to the group where only benignan cy and malignancy were distinguished. 5. FNAC in a group of patients w ith follicular lesion had sensitivity 87.5%, specificity 98.3% and acc uracy 97.0%. 6. The sensitivity of frozen section for malignancy in ou r study was 71.4%, specifically 85.7%, accuracy 77.8%, the positive pr edictive value 83.3% and the negative predictive value 73.3%. Conclusi on: According to our results we strongly recommend fine needle aspirat ion cytology as a routine preoperative investigation in all thyroid no dules including toxic goiters. Our results confirm that FNAC can ident ify precancerous lesions as well as identify between benign and malign ant follicular lesions. Surgeons should use frozen section in cases of uncertain FNAC but should not rely on its negative result.