Incorporation of biological risk into the eighth edition of AJCC
TNM staging system
With the TNM-stratified analysis, there was no significant survival
difference between low-risk group and middle-risk group in stage I,
while the OS of the two groups was significantly better than that of
high-risk group in stage I (Figure 4,A ). Of the patients in
stage II, the survival differences
were significant between each two groups (Figure 4,B ). Of the
pateints in stage III, there was no significant survival difference
among the three groups
(Figure 4,C ). The OS of
patients in low-risk and middle-risk group, who were at stage I was
similar to that of patients in low-risk group who were at stage II. The
OS of patients in high-risk group who were at stage I was similar to
that of patients in middle-risk group who were at stage II. The OS of
patients in high-risk group who were at stage II was similar to that of
patients in stage III(Figure 4,D ).
According to the results of the strata analysis, we incorporated the
biological risk into the eighth edition of the TNM staging system and
introduced our modified TNM (mTNM) staging system (TableIV ). In the mTNM staging system, the 5-year OS rates of stage
mI, mII and mIII were 31.5%, 17.2% and 7.2%, respectively
(χ2=78.603, P <0.001). In the TNM staging
system, the 5-year OS rates of stage I, II and III were 28.2%, 14.9%
and 7.7%, respectively (χ2=37.794, P
<0.001) (Table V, Figure 5 A,B ). Then, the mTNM stage
and the factors associated with OS in the univariate analysis were
included in the multivariate analysis again. This time, age at surgery,
postoperative adjuvant chemotherapy and mTNM stage were found to be
independent prognostic factors for OS. The, biological risk and TNM
stage were not significant in the multivariate analysis (Table
III ).