대장암 환자에서의 근치적 수술 후 복막재발의 발생 양상과 종양학적 결과 = Patterns of Peritoneal Recurrence and Oncologic Outcomes after Curative Resection for Colorectal Cancer

다국어 초록 (Multilingual Abstract)

Purpose
Peritoneal metastasis (PM) after curative resection for colorectal cancer (CRC) is difficult to detect early and carries a poor prognosis. While advanced T stage is associated with PM, how metastatic patterns shift across the pathologic T stages remain insufficiently defined. This study aimed to assess recurrence patterns of PM after curative CRC surgery and to identify associated risk factors.

Materials and Methods
A retrospective cohort study included 4,427 patients with stage I–III CRC who underwent curative resection at Asan Medical Center from January 2012 to December 2017. Recurrence site distribution, recurrence-free survival (RFS), and peritoneal metastasis–free survival (PMFS) were analyzed by T stage. Risk factors for PM were also evaluated. External cohort was a multicenter, international cohort of 3,057 patients with right-sided colon cancer who underwent minimally invasive surgery from January 2015 to December 2020 from eight institutions.

Results
In the primary cohort, PM was the most frequent recurrence site in T4 CRC (13.0%), surpassing lung (9.8%) and liver (6.6%) metastases. The 5-year PMFS was significantly lower in T4 (84.6%) than in T3 (98.0%). In the T/N strata analysis, the 5-year cumulative PM incidence was significantly higher in T4N0 (9.3%) compared to T3N+ (3.2%, p<0.001). On multivariable analysis, T4 stage was independent risk factor for PM (vs. T2; HR 17.2). These results were replicated in the external cohort: PM was the most common recurrence in T4 (11.9%), and T4N0 showed a higher PM incidence than T3N+ (7.9% vs. 4.1%).

Conclusion
Pathologic T4 colorectal cancer exhibits a distinct recurrence pattern, with PM being the predominant site. T4 stage was identified as an independent risk factor for PM, findings that were validated in an independent external cohort. These results have important implications for surveillance protocols and treatment planning strategies.

목차 (Table of Contents)

• 1. 목차 i
• 2. 영문 초록 ii
• 3. Introduction 1
• 4. Methods 3
• 5. Results 7
• 6. Discussion 13
• 7. Conclusion 18
• 8. 참고문헌 19
• 9. Tables 23
• 10. Figures 30
• 11. Figure legends 40
• 12. 국문 초록 41