Efficacy of needle biopsy in postradiation thyroid disease.

Abstract

Retrospective review was carried out of 124 patients with nodular disease of the thyroid gland and a history of radiation exposure who had undergone needle aspiration biopsy. Latency period from time of radiation varied from 2 to 50 years; but in 92 patients it exceeded 2 decades. Our patient group included those with occupational exposure and a past history of radiation for cancer. Incidence of cancer in the entire group was 49% but, for solitary lesions, this was increased to 56%, while only a 30% incidence of cancer was found in cases of multinodular goiters. Accuracy of needle aspiration biopsy overall was 74%: for the group with cancer--90%, for the group with adenomas--65%, and for the group with "benign" tumors--83%. Further assessment of needle technique indicated a sensitivity of 70%, specificity of 90%, positive predictive value of 90%, and negative predictive value of 83% to 65%. The accuracy could be increased to 84% if all adenomas were considered as possible malignancies. Eighteen percent of our patients had second tumors in the head and neck or breast area. Near-total thyroidectomy was considered to be the preferred procedure without accidental nerve injury and was done in one case of hypoparathyroidism after excision of an extensive tracheal invasive cancer. No evidence of death, recurrence, or metastasis as a result of thyroid cancer has been noted. While needle biopsy is indispensable to intelligent management, the history of radiation to the head and neck area must be preeminent in the selection of patients for surgical treatment. Conservative management appears to be reasonable in those patients with "benign" cytology, a less than 1 cm nodule, multinodularity, a functioning thyroid scan result, but persistence in the face of a lack of response to conservative management does not appear to be warranted.