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Session: ePoster: Colon and Colorectal Cancer 1 (Sun8)

EP260 - Long-Term And Short-Term Outcomes Of Minimal Invasive Anterior Resection With Different Preoperative Localization Methods: A Single Center Experience

Sunday, May 11, 2025
9:00 AM - 9:05 AM PT
Location: Monitor 4, Sails Pavilion, Upper Level

    ePoster Presenter(s)

  • Ching Shiang Lin, MD

    Resident
    Department of Colorectal Surgery, Taichung Veterans General Hospital, Taichung Taiwan, R.O.C.
    Taichung City, Taichung, Taiwan (Republic of China)

    All of the relevant financial relationships listed below have been mitigated.
    This individual has no financial relationships with ineligible companies.

    View ePoster

    • Author(s)

  • Chang Lin Lin

    Attending physician
    colorectal surgery
    Taichung, Taichung, Taiwan (Republic of China)

    All of the relevant financial relationships listed below have been mitigated.
    This individual has no financial relationships with ineligible companies.

All of the relevant financial relationships listed below have been mitigated.
Ching Shiang Lin, MD: This individual has no financial relationships with ineligible companies.
Chang Lin Lin: This individual has no financial relationships with ineligible companies.
Purpose/Background: The use of preoperative localization techniques, such as endoscopic tattooing and metallic clip placement, has gained popularity in laparoscopic colorectal surgery. These methods have been shown to improve surgical planning, ensure appropriate resection margins, and reduce the risk of re-excision or the need for intraoperative colonoscopy. However, the impact of preoperative localization on long-term patient outcomes has not been thoroughly investigated. This study aims to analyze the long-term outcomes of minimally invasive anterior resection with and without preoperative localization.

Methods/Interventions: This study involved patients who underwent elective minimal invasive anterior resection at a single institution between January 2016 and December 2019. Collected data encompassed patient characteristics, preoperative localization techniques, operative outcomes, length of hospital stay, postoperative complications, 5-year overall survival, and disease-free survival.

Results/Outcomes: A total of 296 patients underwent elective minimal invasive anterior resection at our institution. Of these, 99 patients (33.4%) received preoperative localization via either metallic clip placement or endoscopic tattooing. The localization group demonstrated a significantly improved resection margin (4.0 cm vs. 3.0 cm; p< 0.001) and a reduced frequency of intraoperative colonoscopy (3.0% vs. 18.8%; p< 0.001). However, there was no statistically significant difference between the groups in 5-year overall survival (89.7% vs. 90.0%; p=0.486) or disease-free survival (82.0% vs. 76.5%; p=0.242). The ROC curve for surgical margin shows an AUC of 0.522 (95% CI: 0.463–0.580; p=0.613) for predicting PFS and an AUC of 0.505 (95% CI: 0.447–0.563; p=0.931) for predicting OS.
In subgroup analysis, patients with low-grade tumors in the localization group had a significantly better resection margin (3.7 cm vs. 3.0 cm; p=0.009), but no statistically significant difference was observed in 5-year overall survival (100% vs. 97.4%; p=0.197) or disease-free survival (93.8% vs. 94.4%; p=0.913). Among patients with locally advanced tumors, a superior resection margin was also observed in the localization group (4.0 cm vs. 3.0 cm; p=0.012), yet no statistically significant difference was found in 5-year overall survival (79.7% vs. 80.1%; p=0.934) or disease-free survival (60.3% vs. 52.7%; p=0.461).

Conclusion/Discussion: Preoperative localization techniques in elective minimally invasive anterior resection can improve resection margins, reducing the need for re-excision and intraoperative colonoscopy. However, the improved resection margin does not significantly affect 5-year overall survival or disease-free survival. Moreover, no specific resection margin threshold was found to significantly enhance long-term patient outcomes.

Kaplan-Meier Survival Curve Analysis of Overall Survival in Colon Cancer Patients Undergoing Minimal Invasive Anterior Resection: Localization group v.s. Non-localization Group.
This Kaplan-Meier survival curve compares the 5-year overall survival between colon cancer patients in the localization group (89.7%) and the non-localization group (90.0%) after Minimal Invasive Anterior Resection, with a p-value of 0.486.

ROC Curve Analysis of nearest free margin as a Predictor of Overall Survival in Colon Cancer Patients Undergoing Minimal Invasive Anterior Resection.
The ROC curve for nearest free margin shows an AUC of 0.505 (95% CI: 0.447–0.563; p=0.931) for predicting overall survival.