Preferred Surgical Approach for Indeterminate Thyroid Nodules

How to Proceed with Cytologically Indeterminate Nodules on FNA

Surgeon in operating room using instrumentationIn evaluating thyroid nodules, fine needle aspiration (FNA) biopsy is the critical initial diagnostic test. If the results are indeterminate, thyroid surgery is often undertaken in order to clear up any suspicion of cancer.  Researchers in Vancouver, British Columbia, Canada, published a study on this indeterminate cytology on FNA issue.  They were looking at the cytological distribution, utility of clinicopathologic characteristics for malignancy prediction, and how many people are found to have cancer (via surgery) after the indeterminate FNA.

The study—“Hemithyroidectomy is the preferred initial operative approach for an indeterminate fina needle aspiration biopsy diagnosis”—was published in the June 2012 edition of the Canadian Journal of Surgery.

This was a retrospective study of 1,040 consecutive primary thyroid operations. Those operations were done during an 8-year period at a tertiary care endocrine referral center in Canada.  Neoplasms included in the study were those that, upon FNA biopsy, were suspicious for—but not diagnostic of—papillary carcinoma (IP) and those neoplasms with cellular atypia (IA).  Follicular neoplasm (FN) and Hurthle cell neoplasm (HN) were also reviewed.

There were 380 patients with cytologically indeterminate thyroid nodules on FNA biopsy.  The breakdown by type was:

  • 252 (66%) with FN
  • 47 (12%) with HN
  • 44 (12%) with IP
  • 26 (7%) with IA
  • 11 (4%) with mixed diagnoses

Pathological evaluation revealed malignant nodules in 102 (27%) of the patients.  That was in 49 (19%) with FN, 11 (23%) with HN, 28 (64%) with IP, and 9 (35%) with IA.

In 196 out of 225 (87%) of FN patients, a hemithyroidectomy was adequate definitive treatment; it was adequate in 39 out of 42 (93%) of patients with HN.

For FN patients, a smaller tumor size was significantly associated with a cancer diagnosis (p = 0.004).  In IP patients, right thyroid lobe location was significantly associated with a cancer diagnosis (p = 0.012).  (Note:  On corrected analyses for multiple comparisons, these were non-significant.)

In conclusion, this study finds that hemithyroidectomy is the optimal initial and definitive surgery for most patients with indeterminate thyroid nodules on fine needle aspiration.

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