title: What is the role of lymph nodal metastases and lymphadenectomy in the surgical treatment and prognosis of thymic carcinomas and carcinoids?
abstract: A best evidence topic in thoracic surgery was written according to a structured protocol. We looked at the clinical relevance of lymph node involvement and nodal (N) stage, in thymomas, thymic carcinomas and carcinoids. The possible role of lymphadenectomy in addition to thymectomy was also evaluated. A total of 605 papers were found, of which nine represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers were tabulated. In the Yamakawa-Masaoka classification, based on 226 patients, lymph nodes were classified as anterior mediastinal (N1), defined as nodes surrounding the thymus gland; intrathoracic (N2), all nodes within the thorax excluding N1; and extrathoracic nodes (N3). Kondo validated the Yamakawa-Masaoka classification in a multicentric cohort of 1320 patients. Thymomas presented nodal involvement in 1.8% of cases, carcinomas in 27% of cases, and carcinoids in 28% of cases. The role of nodal status in defining the stage was even more emphasized in the staging system developed by Tsuchiya for thymic carcinomas. In the Istituto Nazionale Tumori classification, thymomas with N1 or N2 were considered as locally advanced disease with a 95-month disease-free survival rate for locally advanced disease of 46.9 vs 98.6% for locally restricted disease (absence of nodal involvement). Weissferdt and Moran, on a series of 65 thymic carcinomas, underlined the clinical relevance of nodal involvement. Positive lymph nodes were associated with significantly worse survival (P = 0.01070). Okuma, in a series of 68 advanced stage thymic carcinomas, showed that curative-intent surgical treatment was related to prolonged survival (P = 0.03). In particular, IVb tumours due to node-only involvement had better survival when radical resection was achieved when compared with IVb due to distant metastases (P = 0.03). Sung et al. showed the importance of harvesting 10 or more lymph nodes and dissecting intrathoracic lymph nodes to ensure a more complete stadiation of thymic carcinomas. The results underline the clinical relevance and prognostic value of nodal involvement in thymic carcinomas and carcinoids. In these cases, lymphadenectomy is desirable to allow the real definition of N status.
authors.affiliation: Thoracic Surgery Unit, S. Croce e Carle Hospital, Cuneo, Italy vitimassa@hotmail.it.
authors.forename: Andrea
authors.initials: A
authors.lastname: Viti
authors.affiliation: Thoracic Surgery Unit, Sacro Cuore Hospital, Negrar-Verona, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Bertolaccini
authors.affiliation: Thoracic Surgery Unit, Sacro Cuore Hospital, Negrar-Verona, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Terzi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019985:Benchmarking; D002276:Carcinoid Tumor / Q000401:mortality / Q000556:secondary* / Q000601:surgery*; D018572:Disease-Free Survival; D019317:Evidence-Based Medicine; D005260:Female; D006801:Humans; D008197:Lymph Node Excision / Q000009:adverse effects / Q000401:mortality; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D012307:Risk Factors; D013934:Thymectomy / Q000009:adverse effects / Q000401:mortality; D013945:Thymoma / Q000401:mortality / Q000556:secondary* / Q000601:surgery*; D013953:Thymus Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
keywords: Lymph node metastases; Lymphadenectomy; Prognosis; Review; TNM classification; Thymic carcinoma; Thymoma