[The validity and problems of a new staging system for lung cancer from the point of view of surgical results].
The validity and problems of the new staging system for resected lung cancer were assessed. In the new staging system for primary lung cancer, stage I is divided into two groups (A and B) on the basis of the tumor diameter. The boundary is 30 mm in maximum diameter of the tumor. On the other hand, intrapulmonary satellite nodules in the resected lung (PM1) are considered as T4. This means that a patient with PM1 is classified as stage IIIB or IV. The five-year cumulative survival rates of 191 consecutive patients of T1 or T2N0M0 who had undergone complete lung resection were calculated. The patients were divided two groups on the basis of the boundaries of the tumor diameter, such as 15, 20, 25, 30 and 40 mm (The tumor diameter in group A is the boundary and less than boundary and the diameter in group B is more than the boundary), and the cumulative survival rates of the two groups were compared. The 5-year cumulative survival rate (Kaplan-Meier survival rate) of each group and the p-value (logrank test) were 85.0%, and 0.463 in the case of the boundary of 15 mm; 84.8%, 79.9%, and 0.374 in the case of 20 mm, 82.3%, 80.0%, and 0.553 in the case of 25 mm, 79.5, 83.5, 0.524 in the case of 30 mm and 81.0%, 82.2%, and 0.783 in the case of 40 mm. In all cases, there were no significant differences between the rates in the two groups. On the other hand, 15 cases of T4N0M0 lung cancer included 12 cases of pm1, 2 cases of p3 and 1 case of d2. The five-year cumulative survival rate for T4N0M0 patients with pm1 was 71.1%, which was similar to the rate for stage I or II patients, while the two T4N0M0 patients with p3 died of recurrences of lung cancer at 10 and 13 months after the operation, and the T4N0M0 patient with d2 died of local recurrence of lung cancer 60 months postoperatively. We concluded that the sub-classification of stage I on the basis of the boundary of tumor diameter was meaningless, if the boundary was between 15 and 40 mm and that N0M0 patients with PM1 should be classified as stage II or less, or as 1 grade up of T status.
Watanabe
A
A
2nd Department of Surgery, Sapporo Medical University School of Medicine, Japan.
Tabata
A
A
Ingu
A
A
Watanabe
T
T
Ichimiya
Y
Y
Kusajima
K
K
Abe
T
T
Abe
S
S
Satoh
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D011013:Pneumonectomy; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate