Pre-operative diagnosis of thyroid cancer: Clinical, radiological and pathological correlation

Abstract

Aim. Ultrasonography and ne-needle aspiration biopsy (FNAB) are the mainstays of diagnosing thyroid cancer accurately and reducing the number of diagnostic lobectomies. No benchmark for diagnostic accuracy has been published in the South African context. is singleinstitution
study addresses this decit.
Methods. e oncology, pathology and surgical records of all patients diagnosed with thyroid carcinoma from 2004 to 2010 at Groote Schuur
Hospital, Cape Town, South Africa, were reviewed and data were recorded on a standardised condential proforma. e ndings on preoperative clinical assessment, ultrasound and FNAB were correlated with the histopathology results. Diagnostic accuracy for thyroid cancer
was determined by correlating pre-operative investigations with the final diagnosis. Sensitivity of ultrasound and FNAB were calculated.
Results. A total of 109 patients, 79 female and 30 male, were identied. e majority (99, 90.8%) had well-dierentiated thyroid cancers (56 papillary, 30 follicular, 10 mixed and 3 Hurtle cell carcinomas). ere were 6 anaplastic and 4 medullary carcinomas. Of the 109 patients 38 had a denite pre-operative diagnosis, in 61 a malignant tumour was suspected, and 10 had surgery for benign disease. FNAB was inadequate in 11 cases and the ndings indicated a benign lesion in 47, a suspicious lesion in 13 and a malignant lesion in 38 patients diagnosed with thyroid carcinoma. FNAB diagnosed all patients with medullary and anaplastic carcinoma but less than half of those with well-dierentiated thyroid carcinoma. Ultrasound scans detected at least one suspicious feature in 44 patients. Microcalcication was the most common sign.

Conclusion. e rate of pre-operative diagnosis of well-dierentiated thyroid carcinomas in this unit is under 50%, well below international norms. Our standard practice needs to change to include ultrasound-guided FNAB and standardised reporting of high-resolution ultrasound and cytology, before reassessment of our diagnostic accuracy.