Retrospective evaluation of diagnostic analysis in thyroid cancer patients

Thyroid nodules are common in the society. The incidence of malignancy in thyroid nodules varies between 8-13%. Thyroid cancer is the most common endocrine malignancy. Its incidence in the society is 2-4%, and the prevalence of thyroid cancer increases every year due to the widespread use of diagnostic tests and imaging, and epidemiological factors. The mortality rate of thyroid cancers is below 10%, and the most common subtype is papillary carcinoma with 85-90%. Apart from papillary carcinoma of the thyroid, there are subtypes of follicular carcinoma, hurthle cell carcinoma, medullary carcinoma, and anaplastic carcinoma. Thyroid lymphomas and metastases of other cancers may also rarely involve the thyroid gland. Anamnesis, physical examination, laboratory and imaging characteristics of the nodule are important in the preoperative evaluation of thyroid nodule and cancer cases, the frequency of which has increased in recent years. Ultrasonography (USG) is the most commonly used imaging method. The gold standard method in the preoperative diagnosis of thyroid cancer is fine needle aspiration biopsy (FNAB). The sensitivity of USG in diagnosis is 56.25%, the specificity is 95.90%; the sensitivity of FNAB is 81.25% and the specificity is 93.70%. Although FNAB is the gold standard, it cannot diagnose 2 out of every 10 thyroid cancers. Preoperative cytological and postoperative pathological diagnoses may differ in thyroid nodules. The aim of our study is to compare demographic, clinical, laboratory and imaging findings in patients with different thyroid cancer pathologies and to analyze these findings in patients with pathology mismatch with cytological evaluation and to reveal possible parameters that we can use to eliminate the discrepancy. In our study; demographic information, admission complaints, preoperative laboratory, USG and FNAB cytology results, and postoperative pathology and follow up results of 467 cases diagnosed with thyroid cancer in the outpatient clinic of Bursa Uludağ University Faculty of Medicine, Department of Internal Medicine, Department of Endocrinology and Metabolic Diseases between 2014 and 2020 were analyzed retrospectively from file records. Of the patients, 85.70% (n=400, 80,5% female) papillary thyroid cancer; 7.10% (n=33, 72.2% female) medullary thyroid cancer; 5.10% follicular thyroid cancer (n=24, 62.5% female); 1.10% (n=5, 100% female) hurthle Cell thyroid cancer and 1.10% (n=5, 60% female) anaplastic cancer were diagnosed. The median age at diagnosis of the patients was 44 years, with the lowest medullary thyroid cancer, and the highest in anaplastic cancer with 66 years. Dyspnea was most common in anaplastic cancer (60%), and dysphagia was most common in hurthle cell cancer (60%). In USG features, 83.50% of malignant nodules did not have hypoechoic halos, 46.10% had microcalcifications, 14.60% had irregular borders, 12.30% had central vascularization, and 15.50% had suspicious lymph nodes in the neck. The presence of suspicious lymph nodes in the neck at the time of diagnosis was most common in medullary (45.5%) and anaplastic (33.3%) cancers. All patients had preoperative FNAB and surgery. The compatibility of FNAB cytology and post-surgical pathology was 64.80%. The results of our study indicated that the use of demographic characteristics, admission symptoms, laboratory and imaging methods together with FNAB will increase the rate of early and accurate diagnosis, and decrease the discrepancies between preoperative cytological and postoperative pathological diagnoses. Keywords: Thyroid cancer, classification, symptom, ultrasonography, FNAB, cytology, pathology