Objective:To explore the epidemiological and pathological characteristics of multiple primary malignant tumors (MPMTs) accompanied with colorectal malignancies.Methods:The MPMTs patients with colorectal malignant tumors admitted to the Second Affiliated Hospital of Zhejiang University School of Medicine from January 2013 to December 2019 were screened, and the data of gender, age, onset interval, lesion distribution, TNM stage, and pathological type were collected. Then we analyzed the epidemiological characteristics and clinicopathological characteristics.Results:A total of 235 MPMTs patients with colorectal malignancies were treated, accounting for 4.00% of the 5878 patients with colorectal malignancies during the same period. There were 154 males and 81 females, with a male-to-female ratio of 1.90∶1. The median age at diagnosis of the first primary cancer was 64 years. There were 90 synchronous multiple primary carcinomas (SC) patients (38.30%) and 145 metachronous multiple primary carcinomas (MC) patients (61.70%), and the age of first primary cancer diagnosis in SC patients was older than that in MC patients (65 and 62 years, respectively, P=0.022). The median onset interval was 13.25 months (95% CI: 19.61, 27.23 months), and the age at diagnosis of the first primary cancer was negatively correlated with the onset interval ( r=-0.224, P<0.001). There were 257 colorectal malignant tumor lesions in 235 patients, which were distributed in all intestinal segments. The TNM stages were mainly Ⅱ and Ⅲ, and the pathological type was mainly adenocarcinoma. There were no significant differences in the distribution of intestinal segments, TNM stages and pathological types of colorectal malignant tumors between the SC group and the MC group (all P>0.05). There were 234 extraintestinal lesions, mainly distributed in the lung (48), stomach (45), and liver and gallbladder (25). The proportion of extraintestinal lesions located in the stomach of SC patients was 32.18% (28/87), which was higher than that of MC patients [11.56% (17/147), P<0.001]; the proportion of extraintestinal lesions located in the thyroid of SC patients was 2.30% (2/87), lower than that of MC patients [10.20% (15/147), P=0.024]. Conclusions:Approximately 4% of patients with colorectal malignant tumors suffer from two or more malignant tumors, slightly higher in male than in female, and slightly higher in MC patients than in SC patients. The diagnosis age of the first and second primary malignant tumors is mainly concentrated among 55-75 years old, and the interval is inversely related to the diagnosis age of the first primary malignant tumor. The colorectal malignant tumors of SC and MC patients are distributed in all intestinal segments, and the pathological stages are mainly stage Ⅱ and Ⅲ, while the pathological types are mainly adenocarcinoma. Extraintestinal lesions are mostly located in the lungs and stomach.

Objective:To explore the epidemiological and pathological characteristics of multiple primary malignant tumors (MPMTs) accompanied with colorectal malignancies.Methods:The MPMTs patients with colorectal malignant tumors admitted to the Second Affiliated Hospital of Zhejiang University School of Medicine from January 2013 to December 2019 were screened, and the data of gender, age, onset interval, lesion distribution, TNM stage, and pathological type were collected. Then we analyzed the epidemiological characteristics and clinicopathological characteristics.Results:A total of 235 MPMTs patients with colorectal malignancies were treated, accounting for 4.00% of the 5878 patients with colorectal malignancies during the same period. There were 154 males and 81 females, with a male-to-female ratio of 1.90∶1. The median age at diagnosis of the first primary cancer was 64 years. There were 90 synchronous multiple primary carcinomas (SC) patients (38.30%) and 145 metachronous multiple primary carcinomas (MC) patients (61.70%), and the age of first primary cancer diagnosis in SC patients was older than that in MC patients (65 and 62 years, respectively, P=0.022). The median onset interval was 13.25 months (95% CI: 19.61, 27.23 months), and the age at diagnosis of the first primary cancer was negatively correlated with the onset interval ( r=-0.224, P<0.001). There were 257 colorectal malignant tumor lesions in 235 patients, which were distributed in all intestinal segments. The TNM stages were mainly Ⅱ and Ⅲ, and the pathological type was mainly adenocarcinoma. There were no significant differences in the distribution of intestinal segments, TNM stages and pathological types of colorectal malignant tumors between the SC group and the MC group (all P>0.05). There were 234 extraintestinal lesions, mainly distributed in the lung (48), stomach (45), and liver and gallbladder (25). The proportion of extraintestinal lesions located in the stomach of SC patients was 32.18% (28/87), which was higher than that of MC patients [11.56% (17/147), P<0.001]; the proportion of extraintestinal lesions located in the thyroid of SC patients was 2.30% (2/87), lower than that of MC patients [10.20% (15/147), P=0.024]. Conclusions:Approximately 4% of patients with colorectal malignant tumors suffer from two or more malignant tumors, slightly higher in male than in female, and slightly higher in MC patients than in SC patients. The diagnosis age of the first and second primary malignant tumors is mainly concentrated among 55-75 years old, and the interval is inversely related to the diagnosis age of the first primary malignant tumor. The colorectal malignant tumors of SC and MC patients are distributed in all intestinal segments, and the pathological stages are mainly stage Ⅱ and Ⅲ, while the pathological types are mainly adenocarcinoma. Extraintestinal lesions are mostly located in the lungs and stomach.