Patient characteristics
After the screening, 244 patients were included in the analysis, including 201 male patients (82.4%), median age 60 (range 38 to 81) at the time of first treatment. A total of 137 (56.1%) patients had an ECOG score of 0, 164 (67.2%) patients had clinical stage II-IVa diseases, 131 (53.7%) patients received a chemotherapy regimen of PF, and 120 (49.2%) patients received radiotherapy using the IFI target delineation method. The median radiation dose was 59.4 Gy (range 50.4 Gy to 66 Gy). A total of 135 (55.3%) patients achieved good short-term responses of CR or PR one month after finishing CCRT. A total of 113 (46.3%) patients underwent CCRT alone, and 131 (53.7%) patients received CCRT + AC. The baseline characteristics are summarized in Table 1. Before matching, more patients were clinical stage III (61.6% vs. 45.1%) in the CCRT + AC group. After propensity score matching, the CCRT + AC group and CCRT alone group included 99 patients each, and their baseline clinical features were well balanced and showed no significant differences (P>0.05) (Table 1).
Table 1 Patient demographic and clinical characteristics before and after PSM. Abbreviations: PSM, propensity score matching; ECOG, Eastern Cooperative Oncology Group
|
Before PSM
|
After PSM
|
|
CCRT
|
CCRT+AC
|
X2
|
p
|
CCRT
|
CCRT+AC
|
X2
|
p
|
Sex
|
|
|
1.081
|
0.298
|
96
|
96
|
0.033
|
0.855
|
Male
|
90
|
111
|
|
|
81
|
80
|
|
|
Female
|
23
|
20
|
|
|
18
|
19
|
|
|
Age
|
|
|
1.217
|
0.270
|
|
|
0.342
|
0.559
|
<60
|
43
|
59
|
|
|
40
|
36
|
|
|
≥60
|
70
|
72
|
|
|
59
|
63
|
|
|
ECOG Scoring
|
|
|
0.401
|
0.527
|
|
|
0.082
|
0.775
|
0
|
61
|
76
|
|
|
54
|
56
|
|
|
1~2
|
52
|
55
|
|
|
45
|
43
|
|
|
Tumor Location
|
|
|
0.489
|
0.921
|
|
|
0.416
|
0.937
|
Cervical
|
9
|
10
|
|
|
9
|
10
|
|
|
Up
|
53
|
62
|
|
|
45
|
48
|
|
|
Middle
|
35
|
44
|
|
|
32
|
28
|
|
|
Down
|
16
|
15
|
|
|
13
|
13
|
|
|
Clinical Stage
|
|
|
6.334
|
0.042
|
|
|
0.617
|
0.735
|
II
|
19
|
14
|
|
|
16
|
13
|
|
|
III
|
51
|
80
|
|
|
48
|
53
|
|
|
IVA
|
43
|
37
|
|
|
35
|
33
|
|
|
T stage
|
|
|
1.576
|
0.455
|
|
|
0.807
|
0.668
|
2
|
21
|
17
|
|
|
18
|
15
|
|
|
3
|
69
|
83
|
|
|
62
|
68
|
|
|
4
|
23
|
31
|
|
|
19
|
16
|
|
|
N stage
|
|
|
3.062
|
0.382
|
|
|
0.527
|
0.913
|
0
|
18
|
27
|
|
|
17
|
15
|
|
|
1
|
50
|
65
|
|
|
45
|
50
|
|
|
2
|
39
|
35
|
|
|
34
|
31
|
|
|
3
|
6
|
4
|
|
|
3
|
3
|
|
|
MacroType
|
|
|
1.044
|
0.791
|
|
|
1.275
|
0.735
|
Fungating
|
27
|
26
|
|
|
23
|
24
|
|
|
Ulcer
|
35
|
41
|
|
|
34
|
28
|
|
|
Medulla
|
33
|
45
|
|
|
25
|
31
|
|
|
Constrictive
|
18
|
19
|
|
|
17
|
16
|
|
|
CT regimen
|
|
|
1.885
|
0.170
|
|
|
0.081
|
0.775
|
PF
|
66
|
65
|
|
|
53
|
55
|
|
|
TP
|
47
|
66
|
|
|
46
|
44
|
|
|
Radiation Dose
|
|
|
0.118
|
0.731
|
|
|
0.028
|
0.867
|
<59.4Gy
|
28
|
30
|
|
|
23
|
24
|
|
|
≥59.4Gy
|
85
|
101
|
|
|
76
|
75
|
|
|
Target delineation
|
|
|
1.942
|
0.163
|
|
|
0.081
|
0.776
|
IFI
|
61
|
59
|
|
|
52
|
50
|
|
|
ENI
|
52
|
72
|
|
|
47
|
49
|
|
|
Short-term response
|
|
|
0.410
|
0.522
|
|
|
0.020
|
0.887
|
Good
|
65
|
70
|
|
|
53
|
54
|
|
|
Poor
|
48
|
61
|
|
|
46
|
45
|
|
|
Survival outcome and failure pattern
The last follow-up was December 31, 2020, while the median time of surveillance was 32 months (range 3 to 94 months). The one-, three-, and five-year PFS rates for the cohort before matching were 63.5%, 36.1%, and 23.2%, respectively. The one-, three-, and five-year OS rates for the cohort before matching were 84.8%, 48.4%, and 17.2%, respectively. The median PFS was calculated to be 20.0 months, while the median OS was 32.5 months.
The median OS in the CCRT alone group was 30.0 months, while that in the CCRT + AC group was 34.0 months, which was not significantly different (hazard ratio [HR] = 0.89 (95% CI, 0.66–1.20), P = 0.422; Fig. 2a). However, the CCRT alone group (14.0 months) exhibited a significantly shorter median PFS than the CCRT + AC group (26.0 months) (HR = 0.73 (0.54–0.99), P = 0.036; Fig. 2b).
The one-, three-, and five-year PFS rates for the cohort after PSM were 62.1%, 36.0%, and 21.9%, respectively. The one-, three-, and five-year OS rates for the cohort after PSM were 80.8%, 47.0%, and 26.9%, respectively. The median PFS was calculated to be 19.0 months, while the median OS was 32.0 months.
In the matched population, the median OS in the CCRT alone group was 33.0 months, while that in the CCRT + AC group was 32.0 months, which was not significantly different (HR = 1.024 (0.74–1.42), P = 0.886; Fig. 2c). The CCRT alone group (14.0 months) exhibited a shorter median PFS than the CCRT + AC group (23.0 months), but the difference was not significant (HR = 0.81 (0.58–1.13), P = 0.197; Fig. 2d).
We also collected failure pattern data for these patients, and the results are shown in Table 2. The CCRT alone cohort exhibited a slightly higher rate of locoregional combined with distant failure than the CCRT + AC cohort before PSM (18.6% vs. 14.5%) and after PSM (16.2% vs. 19.2%). However, the difference was not statistically significant.
Table 2 Patterns of failure for patients who underwent AC before and after PSM. Abbreviations: AC, adjuvant chemotherapy; PSM, propensity score matching.
|
Before PSM
|
After PSM
|
Pattern of failure, n(%)
|
CCRT alone
(n=113)
|
CCRT+AC(n=131)
|
χ2
|
p
|
CCRT alone
(n=99)
|
CCRT+AC (n=99)
|
χ2
|
p
|
Locoregional alone
|
38(33.6)
|
47(35.9)
|
0.784
|
0.853
|
31(31.3)
|
38(38.4)
|
3.032
|
0.387
|
Locoregional and distant
|
21(18.6)
|
19(14.5)
|
|
|
20(20.2)
|
12(12.1)
|
|
|
Distant alone
|
19(16.8)
|
24(18.3)
|
|
|
16(16.2)
|
19(19.2)
|
|
|
No failure
|
35(31.0)
|
41(31.3)
|
|
|
32(32.3)
|
30(30.3)
|
|
|
Subgroup analysis
In the OS subgroup analysis, none of the basic clinical characteristics in the analysis showed a significant predictive effect. It is worth mentioning that the influence of the short-term response on survival was significant (p for interaction 0.036; Fig. 3a), although neither subgroup reached a significant difference.
In the PFS subgroup analysis, the influence of the short-term response on survival was significant (p for interaction 0.023). Only the good short-term response subgroup favoured adjuvant chemotherapy (CCRT + AC versus CCRT alone, HR = 0.54 (0.34–0.88), P = 0.008). The other basic clinical characteristics in the analysis did not show a significant predictive effect (Fig. 3b).
Details of the survival outcomes of the short-term response group were calculated. For patients with a good short-term response, the CCRT alone cohort did not show a significant OS difference compared with the CCRT + AC cohort (median, 38.0 vs 58.0 months, (HR = 0.75 (0.47–1.21), P = 0.235; Fig. 4a). However, the CCRT alone cohort exhibited shorter PFS than the CCRT + AC cohort (median, 14.0 vs. 44.0 months, HR = 0.54 (0.34–0.88), P = 0.008; Fig. 4b).
For those patients with a poor short-term response, the CCRT alone cohort did not show significant OS (median, 21.0 vs 22.0 months, (HR = 1.43(0.90–2.26), P = 0.709; Fig. 4c) or PFS (median, 14.0 vs. 14.0 months, HR = 1.27(0.80–2.01), P = 0.293; Fig. 4d) differences compared with the CCRT + AC cohort.
AC cycles analysis
The median number of AC cycles was 2 and it ranged from 1 to 4. Considering the potential survival benefit of adjuvant chemotherapy for the good short-term response subgroup, we further analysed the influence of AC cycles. Compared with the patients who received two cycles of AC, receiving than two cycles of AC chemotherapy did not significantly improve PFS or OS (Fig. 5a, Fig. 5b).
AC benefit analysis
After PSM, the median value for OS was 33.0 months and that for PFS was 14.0 months in the CCRT alone cohort. As a result, the OS or PFS benefit of AC was defined as exceeding the median OS or PFS of the CCRT alone group patients. Coding 1 for benefit and 0 for no benefit, all survival times of the patients could be transferred to categorical variables based on the AC benefit. Then, univariate logistics analysis showed that sex (male or female), clinical stage (stage II-III or/stage IV), N stage (stage N0-1 or N2-3), short-term response (good or bad) were potential predictive factors for OS, while sex (male or female), clinical stage (stage II-III or stage IV), T stage (stage T2-3 or stage T4), short-term response (good/bad) were potential predictive factors for PFS. Further multivariate analysis showed that a short-term response (good/bad) was a significant influencing factor for OS, and a short-term response (good/bad) and macrotype (fungating + ulcer/medulla + constrictive) were potential influencing factors for PFS. Thus, the influence of a short-term response on the outcome of AC benefit is further proven (Table 3).
Table 3 Univariate and multivariate analyses for prognostic factors of AC benefit through the transformation model.
Prognostic
factors
|
Univariate analyses
|
Multivariate analyses
|
OS
|
PFS
|
OS
|
PFS
|
P
|
HR(95.0% CI)
|
P
|
HR(95.0% CI)
|
P
|
HR(95.0% CI)
|
P
|
HR(95.0% CI)
|
Gender
Male/Female
|
0.059
|
2.786
(0.962-8.068)
|
0.069
|
3.374
(0.908-12.538)
|
0.251
|
2.071
(0.598-7.174)
|
0.204
|
2.513
(0.606-10.421)
|
Age
<60/≥60
|
0.820
|
0.909
(0.401-2.063)
|
0.873
|
0.932
(0.392-2.213)
|
|
|
|
|
ECOG Scoring
0/1~2
|
0.249
|
0.624
(0.280-1.391)
|
0.743
|
1.151
(0.497-2.666)
|
|
|
|
|
Tumor Location
Up/down
|
0.115
|
0.520
(0.231-1.173)
|
0.212
|
0.585
(0.253-1.356)
|
|
|
|
|
Clinical Stage
II-III/IV
|
0.001
|
0.208
(0.082-0.531)
|
0.102
|
0.485
(0.204-1.156)
|
1.000
|
|
|
|
T stage
T2-3/T4
|
0.139
|
0.423
(0.135-1.324)
|
0.050
|
0.335
(0.112-1.001)
|
|
|
0.064
|
0.304
(0.086-1.070)
|
N stage
N0-1/N2-3
|
0.002
|
0.240
(0.097-0.596)
|
0.141
|
0.523
(0.221-1.240)
|
1.000
|
|
|
|
Radiation Dose
<59.4Gy/
≥59.4Gy
|
0.444
|
1.438
(0.568-3.641)
|
0.177
|
1.913
(0.746-4.903)
|
|
|
|
|
MacroType
Fungating+Ulcer/
Medulla+Constrictive
|
0.129
|
0.538
(0.242-1.197)
|
0.004
|
0.280
(0.116-0.673)
|
|
|
0.005
|
0.246
(0.092-0.661)
|
CT Regimen
PF/TP
|
0.893
|
0.947
(0.428-2.093)
|
0.962
|
1.020
(0.443-2.352)
|
|
|
|
|
Target Delineation
ENI/IFI
|
0.922
|
1.040
(0.473-2.288)
|
0.726
|
1.160
(0.506-2.662)
|
|
|
|
|
Short-term response
Good/Bad
|
<0.001
|
5.500
(2.305-13.126)
|
<0.001
|
5.029
(2.039-12.399)
|
<0.001
|
5.969
(2.258-15.776)
|
0.003
|
4.395
(1.650-11.710)
|