Background
The TNM classification of the Unio Internationalis Contra Cancrum was revised for the seventh edition. The major change concerning breast cancer is a change in the stages for patients with T0 or T1N1miM0. In the present study, the seventh edition of the TNM classification was validated in breast cancer.
Methods
The stages of 416 breast cancer patients, treated at our hospital in 1996, were classified according to the TNM classification, sixth and seventh editions, and their prognoses were compared.
Results
Case distribution using the sixth edition was stage 0, 56 cases (13.5 %); stage I, 158 cases (38.0 %); stage II, 130 [A, 102; B, 28] cases (31.2 [A, 24.5; B, 6.7] %); and stage III, 72 [A, 31; B, 8; C, 33] cases (17.3 [A, 7.5; B, 1.9; C, 7.9] %). According to the seventh edition, the stages for 20 patients, accounting for 19.6 % of IIA cases according to the sixth edition, decreased from IIA to IB. The 10-year overall survivals were stage 0, 91.1 %; stage I, 88.6 %; stage II, 80.8 %; and stage III, 63.9 % according to the sixth edition; and stage 0, 91.1 %; stage I, 88.8 %; stage II, 79.1 %; and stage III, 63.9 % according to the seventh edition. Although no significant differences were seen among the survival rates for stages 0 to II according to the sixth edition, there was a significant difference between stage I and II according to the seventh edition (p = 0.026).
Conclusion
The latest revision of the TNM classification is appropriate for breast cancer from the perspective of prognosis.