INCIDENTAL THYROID CANCER COMMON FINDING IN THYROIDECTOMIES 

NEW YORK (Reuters Health) Feb 27 - The rate of incidental thyroid cancer detected among patients who undergo thyroidectomy for apparently benign disease is unexpectedly high, especially in cases of nodular disease, according to a multicenter researcher team.

"These data support consideration of initial total thyroidectomy as the preferred approach for patients referred to the surgeon with bilateral nodular disease," they suggest in a paper online February 11 in the Journal of the American College of Surgeons.

The findings come from an analysis of data on 2,551 patients who underwent thyroidectomy at high-volume centers in Tennessee, Wisconsin, and Florida. On fine-needle biopsy, 1,028 were found to have malignant or indeterminate disease; that is, a cytology diagnosis of malignancy, suspicious for malignancy, follicular lesion or atypia of undetermined significance, and follicular neoplasms.

In the remaining 1,523 patients with presumed benign disease, however, 238 incidental cancers were recorded after thyroidectomy on final pathology, Dr. Carmen C. Solorzano, at Vanderbilt University Medical Center in Nashville, Tennessee, and colleagues report.

"The findings are interesting and maybe not so unexpected," Dr. Solorzano commented in an email to Reuters Health. "We know that in autopsy studies, cancer of the thyroid is found in up to 36% of them."

Incidental cancer rates were significantly higher in the 1,095 patients with nontoxic multinodular goiter (17.5%) and the164 with toxic nodular goiter (18.3%) than in the 264 Graves' disease patients (6.1%; p<0 .01="" according="" p="" report.="" the="" to="">

The presence of lymphocytic thyroiditis was not associated with incidental cancer, but multivariate analysis indicated that younger patients, males, and nodular thyroids were more likely to harbor carcinoma, the investigators found.

They note that the overall incidental cancer rate of 15.6% was higher than has been reported in similar studies, and suggest one reason may be variation in the aggressiveness of evaluations of thyroid tissue after thyroidectomy. However, they point out that rates were similar among the three institutions participating in this study, so a "more plausible explanation is that the overall incidence of thyroid cancer is increasing."

The authors also found that 39% of the incidental cancers were larger than 1 cm.

"The implication for the clinician is that in multi-nodular disease whether hyper- or euthyroid, cancer (papillary) is quite common," Dr. Solorzano commented, "and despite our current approaches (ubiquitous ultrasound and liberal use of fine-needle aspiration) we still miss a lot of them that are >1cm and maybe clinically important."

She and her colleagues explain that while Graves' disease patients are best treated with total thyroidectomy, patients with nodular goiter can be successfully treated by lobectomy. However, in light of the current findings, "a total thyroidectomy in the hands of an experienced thyroid surgeon might be the best treatment for these patients."

Dr. Solorzano sounded a note of caution in this regard. "This is a retrospective study about patients who are already referred to the surgeon so in these patients with bilobar nodular disease one can consider total thyroidectomy. But this was by experienced surgeons so we need to be careful when offering total tx by inexperienced surgeons."

Furthermore, the authors point out another consideration before recommending total thyroidectomy. "The natural history of these incidental cancers is most likely indolent, yet the complications of total thyroidectomy can be lifelong and substantial."

SOURCE: http://bit.ly/YzKV3L

J Am Coll Surg 2013.