title: Prospective trial of unilateral surgery for nonhereditary medullary thyroid carcinoma in patients without germline RET mutations.
abstract: Although sporadic medullary thyroid carcinoma (MTC) tends to be unicentric and confined to one lobe, total thyroidectomy is usually performed because of the risk of a hereditary or bilateral process. Germline RET mutation analysis can discriminate hereditary MTC and truly sporadic, nonhereditary MTC. We analyzed 72 of 94 patients with MTC to establish the genetic nature and the clinical features of nonhereditary MTC. Since 1996 we have prospectively treated 15 patients with nonhereditary MTC (prospective study group, or PSG) according to a unilateral surgery policy. A group of 22 previously operated patients in whom the nonhereditary nature was established served as controls (retrospective study group, or RSG). Systematic central and ipsilateral neck dissection was performed in both groups. Outcome was assessed using postoperative stimulated serum calcitonin levels; a normal value was considered a biochemical cure. All 24 hereditary MTC patients carried germline RET mutations: 8 of 48 patients with apparently sporadic MTC had the mutations, and 6 of the 8 had bilateral MTC. All 40 patients without mutations had a unilateral tumor. In the RSG group 15 of 22 (68%) patients underwent total thyroidectomy, and the biochemical cure rate was 68%. Although only 3 of 15 (20%) of the PSG patients underwent total thyroidectomy, 12 of the 15 (80%) achieved biochemical cure. Univariate analyses revealed that pathologic node involvement- high T and N stages-was adversely related to biochemical cure. The extent of thyroid resection was not related to biochemical cure. Of 20 patients with node involvement, 10 achieved biochemical cure, indicating the importance of systematic neck dissection. Hemithyroidectomy with systematic central and ipsilateral neck dissection is appropriate surgery for nonhereditary MTC.
authors.affiliation: Department of Surgery, Kuma Hospital, 8-2-35 Shimoyamate-dori, Chuo-ku, Kobe 650-0011, Japan. miyauchi@kuma-h.or.jp
authors.forename: Akira
authors.initials: A
authors.lastname: Miyauchi
authors.forename: Fumio
authors.initials: F
authors.lastname: Matsuzuka
authors.forename: Keisuke
authors.initials: K
authors.lastname: Hirai
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Yokozawa
authors.forename: Kaoru
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ito
authors.forename: Keiichi
authors.initials: K
authors.lastname: Nakano
authors.forename: Kanji
authors.initials: K
authors.lastname: Kuma
authors.forename: Hitoyasu
authors.initials: H
authors.lastname: Futami
authors.forename: Ken
authors.initials: K
authors.lastname: Yamaguchi
mesh_terms: D000328:Adult; D000368:Aged; D018276:Carcinoma, Medullary / Q000235:genetics / Q000601:surgery*; D004252:DNA Mutational Analysis; D029721:Drosophila Proteins; D005260:Female; D018095:Germ-Line Mutation; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D011446:Prospective Studies; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000235:genetics*; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases / Q000032:analysis / Q000235:genetics*; D013964:Thyroid Neoplasms / Q000235:genetics / Q000601:surgery*; D013965:Thyroidectomy / Q000379:methods*
chemical_list: D029721:Drosophila Proteins; D011518:Proto-Oncogene Proteins; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; C416649:Ret protein, Drosophila