Minimally Invasive Surgery: Is It a Risk Factor for Postoperative Peritoneal Metastasis in pT4 Colon Cancer?

Performing laparoscopic surgery for T4 colon cancer remains controversial because of concerns about whether its oncologic outcomes are comparable to those of open surgery, and postoperative peritoneal metastasis (PM) has been reported to occur more frequently in laparoscopic colectomy for T4 colon cancer. We investigated whether minimally invasive surgery (MIS) demonstrated a higher PM rate than open surgery and analyzed the risk factors for PM in pT4 colon cancer.

This study included 392 patients with pT4 colon cancer who underwent curative surgery at a referral hospital between January 2000 and December 2018. Patients with previous neoadjuvant therapy, synchronous malignancy, metastasis, or those who underwent hyperthermic intraperitoneal chemotherapy were excluded.

The MIS group had fewer high-risk clinical features, such as tumors too large for endoscope admission or complications like perforation and fistula. The group also exhibited shorter operative time, intraoperative blood loss, multivisceral resection, hospital stay, fewer postoperative complications, smaller tumor size, lower pT4b ratio, and higher pN+ rates. Multivariate analysis revealed that high-risk clinical features, MIS, pT4b, pN+, tumor size < 5 cm, high histological grade, lymphovascular invasion, and postoperative complications were significant risk factors for PM. During the median 59-month follow-up, the 5-year cumulative incidence of PM was elevated in the MIS group (17.5% vs. 8.2%; P = 0.057). No significant differences were observed in the 5-year overall and disease-free survival rates.

Minimally invasive surgery increases the risk of postoperative PM in patients with pT4 colon cancer. Surgeons may require thorough tumor staging and radical resection to prevent PM.