Patients and tumor characteristics
Of 115 ESCC patients enrolled in this retrospective study, chemotherapy consisting of FP was used for 43 (37%) patients, while FGP was used for 73 (63%) patients. The interval between NACRT and surgery was 40 (21–95) days. Surgery entailed complete esophageal resection (R0) in all patients. The median number of dissected lymph nodes was 49 (8–97). We categorized 26 (22%) patients as pT0N0, 10 (8%) as pT0N+, 40 (34%) as pT + N0, and 40 (34%) as pT + N+. Their characteristics are shown in Table 1. The median length of follow-up for censored cases was 55.5 (18–60) months after surgery. Forty-six (40%) patients experienced recurrences during the observation period. Of those, 37 (80%) recurrences were distant metastasis, and 9 (20%) were local metastasis.
Table 1
Clinicopathological features of the ESCC patients enrolled in this retrospective study
Characteristic, n (%) | pCR | | | non pCR | | P |
pT0N0 | | pT0N1-3 | pT1-4N0 | pT1-4N1-3 |
n = 25 | | n = 10 | n = 40 | n = 40 |
Median age (range) | 63 (44–77) | | 65 (53–75) | 66 (43–74) | 63 (41–75) | 0.2402 |
Gender | | | | | | 0.7178 |
Female | 5 (20.0) | | 1 (10.0) | 8 (20.0) | 5 (12.5) | |
Male | 20 (80.0) | | 9 (90.0) | 32 (80.0) | 35 (87.5) | |
Tumor location | | | | | | 0.8228 |
Upper | 5 (20.0) | | 2 (20.0) | 8 (20.0) | 9 (22.5) | |
Middle | 9 (36.0) | | 4 (40.0) | 18 (45.0) | 21 (52.5) | |
Lower | 11 (44.0) | | 4 (40.0) | 14 (35.0) | 10 (25.0) | |
Tumor differentiation | | | | | | 0.5425 |
Not poorly | 20 (80.0) | | 8 (80.0) | 36 (90.0) | 36 (90.0) | |
Poorly | 5 (20.0) | | 2 (20.0) | 4 (10.0) | 4 (10.0) | |
Depth of invasion (cT) | | | | | | 0.0567 |
T1-2 | 5 (20.0) | | 3 (30.0) | 2 (5.0) | 3 (7.5) | |
T3-4 | 20 (80.0) | | 7 (70.0) | 38 (95.0) | 37 (92.5) | |
Lymph node metastasis (cN) | | | | | | 0.5858 |
N1 | 18 (72.0) | | 8 (80.0) | 26 (65.0) | 24 (60.0) | |
N2-3 | 7 (28.0) | | 2 (20.0) | 14 (35.0) | 16 (40.0) | |
Distant metastasis (cM) | | | | | | 0.2138 |
M0 | 19 (76.0) | | 10 (100) | 36 (90.0) | 35 (87.5) | |
M1 ( Lymph node) | 6 (24.0) | | 0 (0) | 4 (10.0) | 5 (12.5) | |
Clinical stage(cStage) | | | | | | 0.1051 |
I | 1 (4.0) | | 1 (10.0) | 2 (5.0) | 0 (0) | |
II | 3 (12.0) | | 2 (20.0) | 0 (0) | 3 (7.5) | |
III | 14 (56.0) | | 6 (60.0) | 34 (85.0) | 31 (77.5) | |
IVA | 1 (4.0) | | 1 (10.0) | 0 (0) | 1 (2.5) | |
IVB | 6 (24.0) | | 0 (0) | 4 (10.0) | 5 (12.5) | |
Recurrence | | | | | | 0.0456* |
Presence | 5 (20.0) | | 4 (40.0) | 15 (37.5) | 22 (55.0) | |
Absence | 20 (80.0) | | 6 (60.0) | 25 (62.5) | 18 (45.0) | |
Prognosis | | | | | | 0.3115 |
Alive | 22 (88.0) | | 6 (60.0) | 27 (67.5) | 24 (60.0) | |
Dead with ESCC | 2 (8.0) | | 3 (30.0) | 10 (25.0) | 14 (35.0) | |
Dead with other diseases | 1 (4.0) | | 1 (10.0) | 3 (7.5) | 2 (5.0) | |
pCR pathological complete response, ESCC esophageal squamous cell carcinoma |
* Statistically significant |
The Survival Rate Of Patients With Non-pcr After Nacrt
Comparison of the survival rates between the pCR and non-pCR groups revealed that pCR patients had significantly better OS, DSS, and RFS than non-pCR patients (Fig. 1a-1c). There were no significant differences in survival between pT0N+, pT + N0, and pT + N + subgroups, though survival among the pT + N + group was the poorest (Fig. 1d-1f).
Relationship between the SUV max reduction rate in the primary tumor and survival in the pT + N + group.
We focused on the SUVmax reduction rate on FDG-PET measured in the primary tumors of 88 patients from whom SUVmax data were collected before and after NACRT. Among those patients, 21 (24.9%), 9 (10.2%), 28 (31.8%), and 30 (34.1%) were categorized as pT0N0, pT0N+, pT + N0, or pT + N+, respectively. The median value of baseline SUVmax and post-NACRT SUVmax were 14.8 (2.9–42.0) and 3.2 (2.0-14.6), respectively. Based on the receiver operating characteristic (ROC) curve, the optimal cutoff value for the SUVmax reduction rate in the primary lesion for OS, DSS, and RFS was 60%. We therefore performed Kaplan-Meier curve analyses using this cutoff value. Among all non-pCR patients, the 5-year OS and DSS were better in patients with a SUVmax reduction rate of 60% or more than in those with a SUVmax reduction rate of less than 60%, though the differences were not statistically significant (Fig. 2a, 2b). However, 5-year RFS for patients with SUVmax reduction rates of 60% or more was significantly better than that for patients with SUVmax reduction rates less than 60% (Fig. 2c).
We next divided the non-pCR patients into the three aforementioned subgroups and analyzed their prognosis using the optimal cutoff value for the SUVmax reduction rate. In the pT0N + subgroup, there were no differences in OS, DSS, and RFS between patients with SUVmax reduction rates of more than 60% and less than 60% (Fig. 3a-3c). In the pT + N0 subgroup, there were also no differences in OS, DSS, or RFS between patients with SUVmax reduction rates greater than or less than 60% (Fig. 4a-4c). By contrast, in the pT + N + subgroup, 5-year OS, DSS, and RFS among patients with SUVmax reductions rates of 60% or more were significantly better than among patients with SUVmax reduction rates less than 60% (Fig. 5a-5c).
Prognostic Analysis Of Os, Dss, And Rfs
We performed univariate and multivariate survival analyses with the pT + N + group (Table 2). Univariate analysis revealed that age (≥ 65 or < 65) and the SUVmax reduction rate in the primary tumor (< 60% or ≥ 60%) were significant prognostic factors affecting 5-year OS and DSS in the pT + N + subgroup. Moreover, univariate analysis of 5-year RFS in the pT + N + group revealed that pathological depth of invasion (pT3-4 or pT1-2), pathological lymph node status (pN2-3 or pN1), and the SUVmax reduction rate in the primary tumor (< 60% or ≥ 60%) were significant prognostic factors. Multivariate survival analysis of 5-year OS, DSS, and RFS in the pT + N + group showed the SUVmax reduction rate was an independent prognostic factor. It thus appears that in pT + N + ESCC patients, the SUVmax reduction rate is clinically useful for predicting 5-year OS, DSS, and RFS.
Table 2
Univariate and multivariate analyses of survival (Cox’s proportional hazards regression models)
Factor | OS |
Univariate | | Multivariate |
P-value | | HR (95% CI) | P-value |
Age (≥ 65 / <65) | 0.0242* | | 4.1216 (1.1369–14.9423) | 0.0311* |
Gender (Male / Female) | 0.9989 | | | |
Location (Middle, Lower / Upper) | 0.1605 | | | |
Differentiation (Not poorly / poorly) | 0.6711 | | | |
cT (T3-4 / T1-2) | 0.9991 | | | |
cN (N2-3 / N1) | 0.7055 | | | |
cM (M1(Lymph node) / M0) | 0.4804 | | | |
pT (T3-4 / T1-2) | 0.2130 | | | |
pN (N2-3 / N1) | 0.0965 | | | |
SUVmax reduction rate in the primary lesion (< 60% / ≥60%) | 0.0007* | | 8.3800 (2.3893–29.3915) | 0.0009* |
Factor | DSS |
Univariate | | Multivariate |
P-value | | HR (95% CI) | P-value |
Age (≥ 65 / <65) | 0.0246* | | 5.2678 (1.2729–21.8008) | 0.0219* |
Gender (Male / Female) | 0.9990 | | | |
Location ( Middle,Lower / Upper) | 0.2356 | | | |
Differentiation (Not poorly / poorly) | 0.9992 | | | |
cT (T3-4 / T1-2) | 0.9992 | | | |
cN (N2-3 / N1) | 0.3436 | | | |
cM (M1(Lymph node) / M0) | 0.3277 | | | |
pT (T3-4 / T1-2) | 0.4104 | | | |
pN (N2-3 / N1) | 0.0969 | | | |
SUVmax reduction rate in the primary lesion (< 60% / ≥60%) | 0.0034* | | 7.6048 (1.9819–29.1798) | 0.0031* |
Factor | RFS |
Univariate | | Multivariate |
P-value | | HR (95% CI) | P-value |
Age (≥ 65 / <65) | 0.1947 | | | |
Gender (Male / Female) | 0.2876 | | | |
Location (Middle, Lower / Upper) | 0.0759 | | | |
Differentiation (Not poorly / poorly) | 0.2910 | | | |
cT (T3-4 / T1-2) | 0.9203 | | | |
cN (N2-3 / N1) | 0.4032 | | | |
cM (M1(Lymph node) / M0) | 0.7506 | | | |
pT (T3-4 / T1-2) | 0.0312* | | 2.5857 (0.8313–8.0423) | 0.1008 |
pN (N2-3 / N1) | 0.0330* | | 0.6968 (0.1794–2.7072) | 0.6019 |
SUVmax reduction rate in the primary lesion (< 60% / ≥60%) | 0.0006* | | 6.2962 (1.4981–26.4625) | 0.0120* |
OS overall survival, DSS disease-specific survival, RFS relapse-free survival, |
HR hazard ratio, CI confidence interval |
* Statistically significant |