4 .1 Univariate Analysis Results
4.1.1 The results of the univariate analysis show that the following factors, including patient gender, presence of underlying diseases, smoking and alcohol history, family history, white blood cell count, neutrophil count, platelet count, CA19-9, CA72-4, PLR, and BRAF status, are not significantly associated with prognosis.
The average disease-free survival (DFS) for males is 47.2 months, while for females, it is 52.1 months. The average overall survival (OS) for males is 50.8 months, and for females, it is 55.8 months. However, these differences are not statistically significant (p-values are 0.234 and 0.202, respectively). Out of 270 patients, 111 (41.1%) had underlying diseases, while 159 (58.9%) did not. The average DFS and OS for the group with underlying diseases were 47.5 months and 51.1 months, respectively. For the group without underlying diseases, the average DFS and OS were 50.0 months and 53.6 months, respectively. However, these differences were not statistically significant.105 patients (38.9%) were smokers, while 165 (61.1%) were non-smokers. The average DFS and OS for the smoking group were 50.7 months and 54.1 months, respectively. For the non-smoking group, the average DFS and OS were 47.9 months and 51.6 months, respectively. However, these differences were not statistically significant. 89 patients (33.0%) were alcohol drinkers, while 181 (67%) were non-drinkers. The average DFS and OS for the group of alcohol drinkers were 48.6 months and 51.5 months, respectively. For the non-drinking group, the average DFS and OS were 49.2 months and 53.1 months, respectively. However, these differences were not statistically significant.18 patients (6.7%) had a family history of the disease, while 252 (93.3%) did not. The average DFS and OS for the group with a family history were 59.2 months and 60.0 months, respectively. For the group without a family history, the average DFS and OS were 48.4 months and 52.2 months, respectively. However, these differences were not statistically significant.Among the 270 patients, 126 (46.7%) had CA19-9 levels greater than 30 U/ml, while 144 (53.3%) had levels less than or equal to 30 U/ml. The group with higher CA19-9 levels had an average DFS and OS of 48.6 months and 51.4 months, respectively. The group with lower CA19-9 levels had an average DFS and OS of 49.3 months and 51.6 months, respectively. However, these differences were not statistically significant.Among the 270 patients, 122 (45.2%) had CA72-4 levels greater than 7 U/ml, while 148 (54.8%) had levels less than or equal to 7 U/ml. The group with higher CA72-4 levels had an average DFS and OS of 46.7 months and 49.8 months, respectively. The group with lower CA72-4 levels had an average DFS and OS of 50.9 months and 54.9 months, respectively. However, these differences were not statistically significant.The average white blood cell count was 6.12 × 10^9/L. Among the patients, 165 (61.1%) had counts greater than 6.12 × 10^9/L, while 105 (38.9%) had counts less than or equal to 6.12 × 10^9/L. The group with higher white blood cell counts had an average DFS and OS of 50.0 months and 53.6 months, respectively. The group with lower white blood cell counts had an average DFS and OS of 47.4 months and 51.0 months, respectively. However, these differences were not statistically significant.The average neutrophil count was 4.11 × 10^9/L. Among the patients, 166 (61.5%) had counts greater than 4.11 × 10^9/L, while 104 (38.5%) had counts less than or equal to 4.11 × 10^9/L. The group with higher neutrophil counts had an average DFS and OS of 49.1 months and 52.8 months, respectively. The group with lower neutrophil counts had an average DFS and OS of 48.8 months and 52.2 months, respectively. However, these differences were not statistically significant.Among the patients, 142 (52.6%) had normal platelet counts, while 128 (47.4%) had higher counts. The group with higher platelet counts had an average DFS and OS of 51.9 months and 54.3 months, respectively. The group with lower platelet counts had an average DFS and OS of 46.4 months and 51.0 months, respectively. However, these differences were not statistically significant. The median PLR was 61.46. Based on the median, the population was divided into two groups. The group with higher PLR values had an average DFS and OS of 49.8 months and 52.6 months, respectively. The group with lower PLR values had an average DFS and OS of 48.2 months and 52.6 months, respectively. However, these differences were not statistically significant. Among the 270 patients, 5 (1.9%) had BRAF mutation, while 295 (98.1%) did not. The group with BRAF mutation had an average DFS and OS of 33.7 months and 35.8 months, respectively. The group without BRAF mutation had an average DFS and OS of 49.3 months and 52.9 months, respectively. However, these differences were not statistically significant.
4.1.2 The univariate analysis shows that patient age, CEA level, lymphocyte count, albumin, NLR, SII, PNI, tumor distance from the anus, tumor size, tumor invasion of the intestinal wall, cT stage, cN stage, TRG grade, KRAS status, and microsatellite status are associated with survival.
Age: The average age was 57.9 years, with a median age of 59 years. Patients were divided into two groups based on whether their age was below or equal to 65 years. There were 203 patients (75.2%) below 65 years of age. The group with older patients had an average DFS and OS of 41.3 months and 45.2 months, respectively. The group with younger patients had an average DFS and OS of 51.6 months and 55.0 months, respectively. These differences were statistically significant.
CEA: Among the 270 patients, 184 (68.1%) had CEA levels greater than 5 ng/mL, while 86 (31.9%) had levels less than or equal to 5 ng/mL. The group with higher CEA levels had an average DFS and OS of 46.0 months and 49.7 months, respectively. The group with lower CEA levels had an average DFS and OS of 54.7 months and 58.1 months, respectively. These differences were statistically significant (p-values were 0.032 and 0.026, respectively).
Lymphocyte Count: The average lymphocyte count was 1.50 × 10^9/L. Among the patients, 164 (60.7%) had counts greater than 1.50 × 10^9/L, while 106 (39.3%) had counts less than or equal to 1.50 × 10^9/L. The group with higher lymphocyte counts had an average DFS and OS of 51.6 months and 55.3 months, respectively. The group with lower lymphocyte counts had an average DFS and OS of 44.7 months and 48.3 months, respectively. DFS showed no significant difference (p=0.065), while OS showed a significant difference (p=0.047).
Albumin: Among the 270 patients, 199 (73.7%) had normal albumin levels, while 71 (26.3%) had lower levels. The group with normal albumin levels had an average DFS and OS of 52.0 months and 55.6 months, respectively. The group with lower albumin levels had an average DFS and OS of 40.4 months and 44.1 months, respectively. These differences were statistically significant (p-values were 0.003 and 0.001, respectively).
NLR: The median NLR was 2.64. Based on the median, the population was divided into two groups. The group with higher NLR values had an average DFS and OS of 42.5 months and 46.2 months, respectively. The group with lower NLR values had an average DFS and OS of 55.4 months and 58.9 months, respectively. These differences were statistically significant (p-values were 0.001 and <0.001, respectively).
SII: The median SII was 683.16. Based on the median, the population was divided into two groups. The group with higher SII values had an average DFS and OS of 45.3 months and 48.4 months, respectively. The group with lower SII values had an average DFS and OS of 52.6 months and 56.7 months, respectively. DFS showed no significant difference (p=0.054), while OS showed a significant difference (p=0.020).
PNI: The median PNI was 49.23. Based on the median, the population was divided into two groups. The group with higher PNI values had an average DFS and OS of 53.2 months and 56.8 months, respectively. The group with lower PNI values had an average DFS and OS of 44.7 months and 48.4 months, respectively. These differences were statistically significant (p-values were 0.025 and 0.018, respectively).
Tumor Distance from the Anus: Among the 270 patients, 210 (77.8%) had tumors located more than 5 cm from the anus, while 60 (22.2%) had tumors located 5 cm or less from the anus. The group with greater tumor distance had an average DFS and OS of 52.0 months and 54.8 months, respectively. The group with shorter tumor distance had an average DFS and OS of 38.5 months and 44.7 months, respectively. These differences were statistically significant (p-values were 0.001 and 0.008, respectively).
Tumor Size: Among the 270 patients, 157 (58.1%) had tumor sizes greater than 5 cm, while 113 (41.9%) had tumor sizes 5 cm or less. The group with larger tumors had an average DFS and OS of 45.6 months and 48.7 months, respectively. The group with smaller tumors had an average DFS and OS of 53.6 months and 58.0 months, respectively. These differences were statistically significant (p-values were 0.046 and 0.012, respectively).
Tumor Invasion of the Intestinal Wall: Among the 270 patients, 218 (80.7%) had tumors that invaded more than 50% of the intestinal wall, while 52 (19.3%) had tumors that invaded 50% or less. The group with more extensive invasion had an average DFS and OS of 45.0 months and 48.3 months, respectively. The group with less extensive invasion had an average DFS and OS of 65.4 months and 70.7 months, respectively. These differences were statistically significant (p-values were 0.001 and <0.001, respectively).
cT Stage: Among the patients, 16 (5.9%) were in stage 1-2, 170 (63.0%) were in stage T3, and 84 (31.1%) were in stage T4. The average DFS and OS for patients in stage 1-2 were 85.1 months and 88.4 months, respectively. For patients in stage T3, the average DFS and OS were 50.6 months and 54.0 months, respectively. For patients in stage T4, the average DFS and OS were 49.0 months and 52.6 months, respectively. These differences were statistically significant (p-values were all <0.001).
cN Stage: Among the patients, 15 (5.6%) were in stage N0, while 255 (94.4%) were in stage N+. The average DFS and OS for patients in stage N0 were 74.0 months and 82.8 months, respectively. For patients in stage N+, the average DFS and OS were 47.5 months and 50.8 months, respectively. These differences were statistically significant (p-values were 0.044 and 0.005, respectively).
TRG Grade: Among the patients, 34 (12.6%) were in grade 0, 151 (55.9%) were in grade 1-2, and 85 (31.5%) were in grade 3. The average DFS and OS for patients in grade 0 were 70.7 months and 71.9 months, respectively. For patients in grade 1-2, the average DFS and OS were 53.0 months and 56.2 months, respectively. For patients in grade 3, the average DFS and OS were 33.1 months and 38.4 months, respectively. These differences were statistically significant (p-values were all <0.001).
KRAS Status: Among the 270 patients, 19 (7%) had KRAS mutations, while 251 (93%) did not. The group with KRAS mutations had an average DFS and OS of 37.3 months and 39.4 months, respectively. The group without KRAS mutations had an average DFS and OS of 49.9 months and 53.6 months, respectively. These differences were statistically significant (p-values were 0.004 and <0.001, respectively).
Microsatellite Status: Among the 270 patients, 20 (7.4%) had microsatellite instability, while 250 (92.6%) had microsatellite stability. The group with microsatellite instability had an average DFS and OS of 78.6 months and 84.9 months, respectively. The group with microsatellite stability had an average DFS and OS of 46.6 months and 50.0 months, respectively. These differences were statistically significant (p-values were 0.005 and 0.001, respectively). (Refer to Table 2 for details).
4.2 Results of Multivariable Analysis
The indices with P<0.05 from the univariate analysis were included in the multivariable analysis. DFS and OS were grouped based on whether they reached 36months, and binary logistic regression analysis was used for the multivariable analysis.The results, as shown in Table 3, indicated that age (=0.385, P=0.007), NLR (HR=0.294, P=0.011), cT stage (HR=0.287, P=0), and TRG grade (HR=0.273, P=0) were significant factors affecting DFS in nCRT patients. Specifically, patients under the age of 65, with NLR lower than the median level, lower cT stage, and lower TRG grade, had longer DFS. Regarding OS, age (HR=0.497, P=0.035), cT stage (HR=0.387, P=0.001), and TRG grade (HR=0.307, P=0) were significant factors affecting OS in nCRT patients (refer to Table 4).