Evaluation of the validity of the 1997 International Union Against Cancer TNM classification of major salivary gland carcinoma.
BACKGROUND
The TNM classification (International Union Against Cancer) of salivary gland carcinoma was revised in 1997. In this study, the authors have evaluated the validity of this new TNM classification and clinical staging in 1683 patients with parotid gland carcinoma.


METHODS
Reclassification was conducted according to the new classification based on the clinical data of 1683 patients registered to the salivary gland division of the Japanese Joint Committee on TNM classification. The 5- and 10-year survival rates according to TNM classification were calculated for 1074 patients whose prognosis could be followed up. Finally, the distribution of the total patient population was analyzed using the new staging and the survival curves for each disease stage.


RESULTS
The variance of the patients for T1 to T4 was appropriate using the new T classification. The 5- and 10-year survival rates corresponded well to the degree of progression of TNM. However, there were only nine patients with Stage III, and marked nonuniformity in the staging was observed. The separation of the survival curves for each stage was not clear, and no significant differences between the survival curves of Stages II and III and Stages III and IV were observed. When the authors classified T1N1M0, T2N1M0, T3N1N0, and T4N0M0, which have 5- and 10-year survival rates similar to Stage III, distribution of patients and separation of the survival curves in each stage improved markedly.


CONCLUSIONS
The results of the current study confirm that the new TNM classification system is valid. However, a significant problem was observed with respect to the new clinical staging. The authors propose that T1N1M0, T2N1M0, T3N1M0, and T4N0M0 be classified as Stage III.
Numata
T
T
Japanese Joint Committee on TNM Classification, the Head and Neck Subcommittee, the Salivary Gland Division, Department of Otorhinolaryngology, Chiba University, School of Medicine, Inohana, Chuo-ku, Chiba City, Chiba, Japan.
Muto
H
H
Shiba
K
K
Nagata
H
H
Terada
N
N
Konno
A
A
D018572:Disease-Free Survival; D006258:Head and Neck Neoplasms / Q000145:classification / Q000401:mortality / Q000473:pathology; D006801:Humans; D007564:Japan; D008207:Lymphatic Metastasis; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012468:Salivary Gland Neoplasms / Q000145:classification* / Q000401:mortality / Q000473:pathology*; D015996:Survival Rate; D013997:Time Factors