Clinicopathologic features and prognosis of synchronous and metachronous multiple primary colorectal cancer.
PURPOSE
Multiple primary colorectal cancers (MPCCs) are different from solitary colorectal cancers in many aspects, which are not well studied. The aim of this study was to clarify the clinicopathological features and prognosis of MPCCs.


METHODS
The data of 64 patients with MPCCs out of 2300 patients with colorectal cancers (CRCs) from January 2009 to December 2017 were retrospectively analyzed. Stratified analysis was conducted based on subtypes and microsatellite status.


RESULTS
The overall incidence of MPCC was 2.8% and the median follow-up duration was 51.5 (range 1-120) months. Metachronous CRCs (MCRCs) are more likely to appear in the right colon (p < 0.05). However, no significant differences regarding age, sex, BMI, tumor size, smoking/drinking history, TNM stage, family history of cancer, and 5-year survival rate were observed between synchronous CRC (SCRC) and MCRC. Advanced TNM stage (III) and the presence of polyps were found to be independent poor prognostic factors for MPCCs. The prevalence of mismatch repair deficiency (dMMR) in MPCCs was 28.1%. Deficient MMR is more likely to appear in younger, lighter MPCC patients with polyps (p < 0.05). Of four mismatch repair proteins, MLH-1, MSH-2, MSH-6, and PMS-2 were negative in nine, nine, five, and nine patients, respectively. The 5-year survival rate did not differ significantly between MMR-proficient (pMMR) and dMMR groups (p = 0.752).


CONCLUSIONS
Synchronous CRC (SCRC) and MCRC might represent similar disease entities with different courses. Deficient MMR is more likely to appear in younger, lighter MPCC patients with polyps and it is an essential indicator for screening Lynch syndrome.
['Zhang|C|C|http://orcid.org/0000-0001-6960-3019', 'Cui|M|M|', 'Xing|J|J|', 'Yang|H|H|', 'Yao|Z|Z|', 'Zhang|N|N|', 'Su|X|X|http://orcid.org/0000-0002-0667-8141']
D000328:Adult D000367:Age Factors D000368:Aged D000369:Aged, 80 and over D003110:Colonic Neoplasms D015179:Colorectal Neoplasms D053843:DNA Mismatch Repair D004268:DNA-Binding Proteins D005260:Female D005500:Follow-Up Studies D006801:Humans D015994:Incidence D007417:Intestinal Polyps D008297:Male D053842:Microsatellite Instability D008875:Middle Aged D000070976:Mismatch Repair Endonuclease PMS2 D000070957:MutL Protein Homolog 1 D051718:MutS Homolog 2 Protein D009367:Neoplasm Staging D009378:Neoplasms, Multiple Primary D016609:Neoplasms, Second Primary D011379:Prognosis D012189:Retrospective Studies D012737:Sex Factors D015996:Survival Rate D055815:Young Adult
Synchronous Metachronous Multiple Colorectal cancer Microsatellite instability