High incidence combination of multiple primary malignant tumors of the digestive system

Abstract

Background: Clinical reports of multiple primary malignant tumors (MPMTs) in the digestive system are increasing. In China, although the survival rate of patients with MPMTs is increasing, the quality of life is very low. Many patients have reached the advanced stage when the second primary tumor is found, resulting in no early intervention and treatment. This is due to the misunderstanding of MPMTs by clinicians, who treat such tumors as metastases. Therefore, before a patient has a second primary tumor, doctors should understand some common combinations of digestive system MPMTs to provide clinical guidance to the patient.

Aim: To explore the high incidence combination of digestive system MPMTs under heterochronism and synchronization.

Methods: A total of 1902 patients with MPMTs at Peking Union Medical College Hospital were analyzed retrospectively. They were divided into metachronous MPMT and synchronous MPMT groups, and then the high incidence combinations of the first primary cancer and the second primary cancer in metachronous cancer and synchronous cancer were sorted. Sex and age differences between metachronous and synchronous tumors were tested by the chi square test and t test, respectively. A P value < 0.05 was considered as statistically significant, and SPSS version 26.0 (SPSS Inc., Chicago, Illinois, United States) was used for statistical analysis.

Results: Among the 1902 patients with MPMTs confirmed by pathology, 1811 (95.2%) cases were secondary primary cancers, 89 (4.7%) cases were tertiary primary cancers, and 2 (0.1%) cases were quaternary primary cancers. Most (88.2%) of the secondary primary cancers were identified as metachronous multiple primary cancers six months after diagnosis of the first primary cancer. The top ten most common MPMTs in the first primary cancer group ranged from high to low as follows: Breast cancer, thyroid cancer, nonuterine cancer, lung cancer, colon cancer, kidney cancer, uterine cancer, bladder cancer, rectal cancer, and gastric cancer. The highest incidence rate of the first primary cancer in male metachronous cancer was lung cancer (11.6%), the highest incidence rate of the second primary cancer was still lung cancer (24.9%), the highest incidence rate of the first primary cancer in female metachronous cancer was breast cancer (32.7%), and the highest incidence rate of the second primary cancer was lung cancer (20.8%). Among them, breast cancer, nonuterine cancer and uterine cancer were female-specific malignant tumor types, and thyroid cancer also accounted for 79.6% of female patients. The top five metachronous cancer combinations, independent of female-specific malignant tumor types and thyroid cancer, were colon cancer and lung cancer (26 cases), kidney cancer and lung cancer (25 cases), rectal cancer and lung cancer (20 cases), gastric cancer and lung cancer (17 cases), and bladder cancer and lung cancer (17 cases). The most common synchronous cancer combination was colon cancer and rectal cancer (15 cases).

Conclusion: Screening for lung cancer should be performed six months after the detection of colon cancer while rectal cancer screening should be performed within six months.

Keywords: Colon cancer; First primary carcinoma; High incidence combinations; Metachronous carcinoma; Multiple primary malignant tumors; Rectal cancer.

Figure 1

Distribution of first and second primary cancers of multiple primary cancers. A: The first primary cancer; B: The second primary cancer.

Figure 2

The proportion of male to female first primary cancer and second primary cancer metachronous cases. A: The first primary cancer is distributed in men with metachronous cancer; B: The second primary cancer is distributed in men with metachronous cancer; C: The first primary cancer is distributed in women with metachronous cancer; D: The second primary cancer is distributed in women with metachronous cancer.

Figure 3

The proportion of male and female cancers of the first primary cancer and the second primary cancer in synchronous cancer. A: The distribution of the first primary cancer in men with synchronous cancer; B: The second primary cancer in men with synchronous cancer; C: The distribution of the first primary cancer in women with metachronous cancer; D: The second primary cancer in women with metachronous cancer.

Figure 4

After excluding the influence of male-female specific malignant tumors, the proportion of male and female digestive system malignant tumors. A: The proportion of male and female primary malignant tumors after excluding the influence of male-female specific cancers, the proportion of male and female primary tumors of metachronous cancer; B: The proportion of male and female primary malignant tumors of synchronous cancer. The red numbers represent the percentage of digestive tumors.

Figure 5

The top ten combined cases of first primary cancer and subsequent second primary cancer of metachronous and simultaneous multiple primary cancer. A: The combination of first primary cancer and second primary cancer of metachronous cancer; B: The combination of first primary cancer and second primary cancer of synchronous cancer.