Evaluation of the new TNM staging system proposed by the International Association for the Study of Lung Cancer at a single institution.
OBJECTIVE
The seventh TNM Classification of Malignant Tumours will be published in 2009. The International Association for the Study of Lung Cancer has proposed a revision of the current pathologic staging system. We illustrated the effects of this new system and pointed out potential problems using a retrospective study of surgical cases of non-small cell lung cancer at our institution.


METHODS
Subjects were 1532 patients for whom current pathologic staging was possible. These data were migrated into the new staging system. The numbers of patients at various stages determined by using the current and new staging systems were, respectively, as follows: IA (n = 700, n = 700), IB (n = 338, n = 249), IIA (n = 49, n = 164), IIB (n = 129, n = 116), IIIA (n = 204, n = 234), IIIB (n = 77, n = 17), and IV (n = 35, n = 52). Prognoses were compared by using the current and the new systems.


RESULTS
By using the new staging system, 5-year survivals by T classifications were as follows: T1a, 82.6%; T1b, 73.3%; T2a, 63.5%; T2b, 50.1%; T3, 40.6%; and T4, 34.6%. There were significant differences between the new T1a and T1b (P = .0026), T1b and T2a (P = .0027), and T2a and T2b (P = .0062) classifications. In the current system 5-year survivals based on pathologic stages were as follows: IA, 84.8%; IB, 72.9%; IIA, 53.8%; IIB, 53.7%; IIIA, 31.8%; IIIB, 34.0%; and IV, 27.1%. There were significant differences between stages IA and IB (P < .0001) and stages IIB and IIIA (P = .0006). In the new system these were as follows: IA, 84.8%; IB, 75.2%; IIA, 62.4%; IIB, 52.1%; IIIA, 32.4%; IIIB, 15.2%; and IV, 30.6%. There were significant differences between stages IA and IB (P = .0004), IB and IIA (P = .0195), IIA and IIB (P = .0257), IIB and IIIA (P = .0040), and IIIA and IIIB (P = .0399).


CONCLUSIONS
Although the outcomes for stages IIIB and IV were reversed, the new pathologic staging system was considered valid based on our single-institution evaluation.
Kameyama
Kotaro
K
Department of Thoracic Surgery, Kurashiki Central Hospital, Okayama, Japan. kk8724@kchnet.or.jp
Takahashi
Mamoru
M
Ohata
Keiji
K
Igai
Hitoshi
H
Yamashina
Akihiko
A
Matsuoka
Tomoaki
T
Nakagawa
Tatsuo
T
Okumura
Norihito
N
D001707:Biopsy, Needle; D002289:Carcinoma, Non-Small-Cell Lung / Q000145:classification / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D015331:Cohort Studies; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000145:classification / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D008297:Male; D009367:Neoplasm Staging / Q000145:classification* / Q000379:methods; D011013:Pneumonectomy / Q000379:methods; D011336:Probability; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D013997:Time Factors