Retrospective study of prognosis of patients with multiple colorectal carcinomas: synchronous versus metachronous makes the difference

Abstract

Purpose: Little is known about difference between synchronous colorectal cancer (SCRC) and metachronous colorectal cancer (MCRC) despite the relevance for this selected patient group. The aim of this retrospective review was to analyze patients with SCRC and MCRC.

Methods: All patients who underwent surgery for SCRC and MCRC between 1982 and 2019 were included in this retrospective analysis of our tertiary referral center. Clinical, histological, and molecular genetic characteristics were analyzed. The primary endpoint was cause-specific survival, evaluated by the Kaplan-Meier method. Secondary endpoints were recurrence-free survival and the identification of prognostic factors.

Results: Overall, 3714 patients were included in this analysis. Of those, 3506 (94.4%) had a primary unifocal colorectal cancer (PCRC), 103 (2.7%) had SCRC, and 105 (2.8%) had MCRC. SCRC occurred more frequently in elderly (p=0.009) and in male patients (p=0.027). There were no differences concerning tumor stages or grading. Patients with SCRC did not show altered recurrence or survival rates, as compared to unifocal tumors. However, MCRC had a lower rate of recurrence, compared to PCRC (24% vs. 41%, p=0.002) and a lower rate of cause-specific death (13% vs. 37%, p<0.001). Five-year cause-specific survival rates were 63±1% for PCRC, 62±6% for SCRC (p=0.588), and 88±4% for MCRC (p<0.001). Multivariable analysis revealed that MCRC were an independent favorable prognostic parameter regarding case-specific survival.

Conclusion: Patients with SCRC seem to not have a worse prognosis compared to patients with PCRC. Noteworthy, patients with MCRC showed better survival rates in this retrospective analysis.

Keywords: Colorectal cancer; Multiple cancers; Prognosis; Synchronous cancers.

Fig. 1

Cause-specific survival (a) and recurrence-free survival (b) of patients with primary colorectal cancer (PCRC), multiple synchronous colorectal cancer (SCRC), and multiple metachronous colorectal cancer (MCRC). Kaplan-Meier curves showed a clear survival benefit for MCRC, compared to PCRC and SCRC. In contrast to survival data, for recurrence free survival, a considerable reduced number of validated patient data were available for SCRC and MCRC. Thus, the informative value of Kaplan-Meier curve (b) may be limited

Fig. 2

Cause-specific survival of patients with (a) PCRC, (b) SCRC, and (c) MCRC, stratified by colon cancer versus rectal cancer. No difference was observed between colon and rectal cancer for each spatial tumor manifestation

Fig. 3

Trend analysis of the twelve patients who underwent resection of their initial primary colorectal cancer (PCRC) as well as for their metachronous colorectal cancer (MCRC) years later at our institution. Every line that illustrates more than just one patient is provided with the respective numbers of patients in this group. A relationship was identified neither for the TNM classification nor for the tumor grading. Regarding the M1-PCRC shown in the left lower panel, one patient with a primary carcinoma of the sigmoid and liver metastasis underwent combined resection (R0) but developed metachronous cancer of the ascending colon with a limited carcinomatosis peritonei 4 years later. He was alive without recurrence 2 years after the last operation