Impact of fine-needle aspiration cytology in thyroidectomy extent and associated surgical morbidity in thyroid cancer.

PURPOSE: To assess the impact of fine-needle aspiration cytology (FNAC) in the extent of surgery in patients with thyroid cancer (TC) and the associated surgical morbidity in primary and completion setting. METHODS: A Swedish nationwide cohort of patients having surgery for TC (n = 2519) from the Scandinavian Quality Register for Thyroid, Parathyroid and Adrenal surgery between 2004 and 2013 was obtained. Data was validated through scrutinizing FNAC and histology reports. RESULTS: Among the 2519 cases operated for TC, the diagnosis was substantiated and validated through the histology report in 2332 cases (92.6%). Among these, 1679 patients (72%) were female, and the median age at TC diagnosis was 52.3 years (range 18-94.6). Less than total thyroidectomy (LTT) was undertaken in 944 whereas total thyroidectomy (TT) in 1388 cases. The intermediate FNAC categories of atypia of undetermined significance/follicular lesion of undetermined significance (AUS/ FLUS), as well as suspicion for follicular neoplasm (SFN) lesions were more often encountered in LTT (n = 314, 33.3%) than TT (n = 63, 4.6%), whereas FNACs suspicion for malignancy and/or malignancy were overrepresented in TT (n = 963, 69.4%). Completion thyroidectomies were undertaken in 553 patients out of 944 that initially had LTT. In 201 cases with cancer lesions > 1 cm, other than FTC (Follicular TC)/ HTC (Hürthle cell TC) subjected to primary LTT, inadequate procedures were undertaken in 81 due to absent, Bethesda I or II FNAC categories, preoperatively. Complications at completion of surgery in this particular setting were 0.5% for RLN palsy (n = 1) and 1% (n = 2) for hypoparathyroidism 6 months postoperatively. The overall postoperative complication rate was higher in primary TT vs. LTT for RLN palsy (4.8% [n = 67] vs. 2.4% [n = 23]; p = 0.003) and permanent hypoparathyroidism (6.8% [n = 95] vs. 0.8% [n = 8]; p < 0.0001). CONCLUSIONS: FNAC results appear to affect surgical planning in TC as intermediate FNAC categories lead more often to LTT. Overall, inadequate procedures necessitating completion surgery are encountered in up to 15% of TC patients subjected to LTT due to absent, inconclusive, or misleading FNAC, preoperatively. However, completion of thyroidectomy in this setting did not yield significant surgical morbidity. Primary LTT is a safer primary approach compared to TT in respect of RLN palsy and permanent hypoparathyroidism complication rates; therefore, primary TT should probably be reserved for lesions > 1 cm or even larger with suspicion for malignancy or malignant FNAC.

Diagnostic sensitivity of fine-needle aspiration cytology in thyroid cancer.

Introduction Fine-needle aspiration cytology (FNAC) is an effective tool in the diagnostic work-up of patients with thyroid nodules. The aim of our study was to assess the diagnostic sensitivity of FNAC in thyroid cancer (TC) in Sweden by correlating the findings of preoperative FNAC with those obtained through final histology of the surgical specimen. Methods A Swedish nationwide cohort of patients having surgery for TC (n = 2519) from the Scandinavian Quality Register for Thyroid, Parathyroid and Adrenal surgery between 2004 and 2013 was obtained. Data was validated through scrutinizing patient FNAC and histology reports. Results Among the 2519 cases operated with a final diagnosis of TC, the diagnosis was substantiated and validated through the histology report in 2332 cases (92.6%), included in the present study. Among these, 1679 patients (72%) were female and the median age at TC diagnosis was 52.3 years (range 18-94.6). In 353 cases (15.1%) FNAC was not performed at all; whereas in the remaining 1965 cases, the diagnostic sensitivity of FNAC was 81.6%. In lesions > 1 cm, FNAC diagnostic sensitivity reached 86.5%, whereas in lesions < 1 cm, FNAC yielded a sensitivity of 61.5%. Approximately 85% of FNACs (n = 1981/2332) were performed using ultra-sonographic (US) guidance. In TC lesions > 1 cm, the diagnostic sensitivity of US-guided FNAC (n = 1504) was 86.9% as compared to 76.9% in clinically applied FNAC without US utilization (n = 118). Conclusions FNAC is performed in most patients operated for TC in Sweden (85%) and retains its value as a tool in TC diagnostic work-up with an overall sensitivity of 82%, reaching 87% in lesions > 1 cm, that harbor clinically relevant TC.