Discussion
death, tumor, CRC, hereditary non-polyposis, hereditary non-adenomatous colorectal cancer, MSI-H, familial adenomatous polyposis, tumors
TUMOR, METASTASIS, INFLAMMATORY BOWEL DISEASE, DISEASE, INFLAMMATORY BOWEL DISEASES, MICROSATELLITE INSTABILITY, FAMILIAL ADENOMATOUS POLYPOSIS, REGRESSION, TUMORS, PATHOGENESIS
SMPCC is a rare CRC subtype characterized by multiple primary synchronous tumors within the colon and rectum. The pathogenesis of SMPCC remains unclear and tends to differ from that of SPCRC. Studies have reported that patients with inflammatory bowel diseases, high microsatellite instability (MSI-H), high CpG island methylation phenotype, hereditary non-polyposis, and familial adenomatous polyposis have a higher risk of developing SMPCC [In this study, we extracted the clinical data of 4386 SMPCC patients from the SEER database. Of these patients, 9.07% and 6.00% died due to all-cause and cancer-specific cause. The univariate and multivariate logistic regression analysis identified older age, no or unknown chemotherapy, no or unknown radiotherapy, and higher TNM stage as predictive risk factors for all-cause and cancer-specific early death. While the risk of early death from all-cause was higher in unmarried patients, the risk of early death from cancer-specific cause was higher for patients diagnosed with poorly or undifferentiated grade.Our predictive nomograms based on the above risk factors achieved good predictive performance for early death in both training and validation cohorts. In addition, our nomogram achieved a higher clinical net benefit than the standard AJCC TNM staging system, thus confirming the clinical value of the nomogram. The AJCC TNM staging system is widely used to predict the prognosis of CRC. Previous studies have shown that tumor invasion depth, lymph node metastasis, and distant organ metastasis are associated with early death in patients with CRC undergoing surgery [There is still a lack of consensus on the optimal postoperative adjuvant therapy for SMPCC patients, particularly for stage II disease. Some studies suggest that SMPCC patients are more at risk of developing micrometastases than SPCRC patients and hence are more likely to benefit from postoperative adjuvant therapy [Similar to previous studies, married patients were less at risk of developing early death [Our findings suggested that extensive resection (total colectomy or proctocolectomy) did not increase the risk of early death in SMPCC patients. Currently, there is no consensus on the extent of surgical resection for SMPCC patients. Hemicolectomy or extended hemicolectomy should be considered for tumors located in the same or adjacent segment. However, extensive resection (total colectomy or proctocolectomy) or multiple segmental resections with synchronous bowel anastomoses are recommended if the tumors were localized in distant segments [This study has several limitations that have to be acknowledged. The data were retrospectively extracted from the SEER database. The lack of quality control in the data included in the SEER database may have biased our results. In addition, we could not explore the association of other potential risk factors for early death in SMPCC, such as nutritional status, carcinoembryonic antigen (CEA), and susceptibility factors (inflammatory bowel disease, familial adenomatous polyposis, and hereditary non-adenomatous colorectal cancer) as this information was not reported in the SEER database. Finally, since the data was collected from a single database, further research is required to validate the generalizability of the nomogram in multiple centers.