Citations

Follicular thyroid carcinoma (FTC) exhibits frequent loss of heterozygosity (LOH) on chromosomes 10q and 3p, suggesting involvement of tumor suppressor genes. We screened 14 FTC (10 Hurthle cell carcinomas and 4 nonoxyphilic FTC), 14 papillary thyroid carcinomas, and 7 follicular adenomas for LOH on chromosome arms 1p, 3p, 3q, 10p, 10q, 11p, 11q, 13q, 17p, and 17q. LOH was more frequent in FTC than in follicular adenoma or papillary thyroid carcinoma. In FTC, rates of LOH on 3p (86%), 17p (72%), and 10q (57%) were higher than the average rate of LOH (33%; P < 0.05). Most frequently involved were 3p21–25 and 17p13.1–13.3, the sites for the VHL (3p25–26) and p53 (17p13.1) tumor suppressors. We, therefore, characterized these genes by dideoxy fingerprinting and DNA sequencing. Two FTC had mutations in p53, but only 1 of these exhibited LOH at 17p. No VHL gene mutations were found. Thus, neither p53 nor VHL genes play a significant role in the pathogenesis of differentiated thyroid cancer. LOH on 17p, but not on 3p or 10q, was correlated with mortality. Accordingly, 3p and 10q LOH may represent early, and 17p LOH late, events in FTC development. The data suggest the presence of novel tumor suppressor genes on chromosomes 3p and 17p that may be important in the pathogenesis of FTC.

AbstractBackgroundIntense postoperative monitoring has resulted in increasing detection of patients with recurrent papillary thyroid cancer (PTC). Our goals included quantifying successful reoperation, and analyzing surgical complications and reasons for relapse.MethodsFrom 1999 to 2008, a total of 410 patients underwent reoperation for PTC relapse. We analyzed post‐reoperative disease outcomes, reasons for relapse, and complications.ResultsBilateral reoperative thyroidectomy was performed in 13 (3 %) patients; lobectomy, 34 (8 %); central neck (VI) soft tissue local recurrence excision, 47 (11.5 %); bilateral VI node dissection, 107 (26 %); unilateral VI dissection, 112 (27 %); levels II–V dissection, 93 (23 %); levels III–V, 86 (21 %); lateral single‐ or two‐compartment dissection, 51 (12 %); and node picking, 20 (5 %) of level VI and 53 (13 %) lateral neck. Complications occurred in 6 %; including hypoparathyroidism, 3 %; unintentional recurrent laryngeal nerve (RLN) paralysis, 3 %; phrenic nerve injury, 0.5 %; spinal accessory nerve injury, 0.5 %; and chyle leak in 1.6 %. Of 380 (93 %) patients with follow‐up (mean 5.2 years); 274 (72 %) patients are alive with no structural evidence of disease, 38 % developed disease relapse (mean 2.1 years), 42 (11 %) died from PTC, and 55 (14 %) are alive with disease. The reason for relapse was a false negative pre‐reoperative ultrasound (US) in 18 (5 %), nodal recurrence in the operative field in 37 (10 %), a combination of these two reasons in 10 (3 %), and disease virulence (local or systemic recurrence) in 81 (21 %).ConclusionsAlthough 72 % of patients were rendered structurally disease free after reoperation, nearly 40 % suffered additional relapse. Improved surgical technique or preoperative localization might positively affect 15–20 %; at least 20 % reflect the biologic aggressiveness of the disease.