BRAFV600E mutation testing for thyroid cancer: avoiding unnecessary surgery

Source:
NICE Quality and Productivity Case Studies
Publisher:
Portsmouth Acute Hospitals NHS Trust
Publication date:
30 December 2015

Abstract

Patients may have surgery to remove all or part of their thyroid gland if cytological examination results suggest they have thyroid cancer.

Cytological examination involves a technique called fine needle aspiration to obtain a sample that is then examined under a microscope to detect cells that might be cancerous.

A major limitation of thyroid cytological examination is that it cannot always distinguish between benign and malignant neoplasms. If the results indicate a possible cancer but are not conclusive, it is common practice to surgically remove the affected lobe of the thyroid for pathological microscopic examination. This leaves the rest of the thyroid intact. If subsequent tests indicate cancer, a second operation is performed to remove the remaining thyroid gland.

In this initiative, when the cytological examination suggests cancer, a mutation test for the BRAF V600E mutation is performed using a commercially available testing kit. The protocol was adapted for use on fine needle aspirate (FNA) samples by using air dried and alcohol fixed FNA cytology smears, rather than formalin fixed paraffin embedded cell blocks. The actual mutation test was unchanged. The method was validated through a blind re-test of samples tested under the previous method. The results were in agreement, indicating a valid method.

The BRAF V600E mutation test is more than 99% specific for thyroid cancer, so a positive result means that it is more than 99% likely that the patient has a malignancy and the entire thyroid can be removed in 1 operation rather than 2. This reduces the risks of complications and shortens the total time spent in hospital and recovery.