# Risk Factors and Patterns of Recurrence in Stage III Perforated Colorectal Cancer: A Single-Center, Retrospective, Observational Study

## TL;DR

This study finds that stage III perforated colorectal cancer has higher recurrence rates due to more advanced tumor stages and lymphatic invasion.

## Contribution

The study identifies specific clinicopathological factors contributing to higher recurrence in perforated colorectal cancer.

## Key findings

- Perforated tumors had higher T4 disease and more severe lymphatic invasion compared to nonperforated tumors.
- Perforated group had fewer dissected lymph nodes and higher complication and mortality rates.
- Recurrence was more common in the perforated group (61%) than in the nonperforated group (35%).

## Abstract

Background: Colorectal perforation generally results in a poor prognosis with a high mortality rate. Malignant colorectal perforation may result in cancer recurrence; however, the reason for higher recurrence rates in perforated than in nonperforated colorectal cancer is unclear. Therefore, we aimed to identify factors influencing stage III perforated colorectal cancer recurrence after a microscopically margin-negative resection (R0) surgery.

Materials and methods: This single-center, retrospective, observational study enrolled patients with stage III colorectal cancer who had undergone R0 surgery between 2007 and 2019. The clinicopathological characteristics and recurrence patterns of patients with perforated (n = 34) versus nonperforated tumors (n = 120) were compared.

Results: The T4 disease proportion was significantly higher, and lymphatic invasion was more severe in the perforated group than in the nonperforated group. Significantly more dissected lymph nodes (n = 17) were observed in the nonperforated group than in the perforated group (n = 11). The rates of postoperative Clavien-Dindo III or higher complications and in-hospital mortality were significantly higher in the perforated group. Of the 23 and 96 patients who underwent long-term follow-up in the perforated and nonperforated groups, recurrence occurred in 14 (61%) and 34 patients (35%), respectively. The proportion of stage IIIC lesions was higher in the recurrence subset of the nonperforated group; however, clinicopathological characteristics did not differ significantly between the subsets of the perforated group.

Conclusions: The higher recurrence rate of stage III perforated colorectal cancer is likely due to higher T classification, lymphatic invasion, and increased lymph node metastases. Factors leading to perforation are likely related to advanced cancer stage.