Perineural invasion is increased in patients receiving colonic stenting as a bridge to surgery: a systematic review and meta-analysis.

BACKGROUND

In recent years, there has been growing concern about the potential association of stent placement as a bridge to surgery in malignant colon obstruction and some anatomopathological findings that could lead to worsening long-term cancer outcomes, such as perineural, vascular and lymphatic invasion. The aim of the present review was to assess the pathological changes found in surgical specimens after stent placement for obstructing colon cancer vs. emergency surgery, and the impact of perineural invasion on survival rates METHODS: MEDLINE, Cochrane Library, Ovid and ISRCTN Registry were searched, with no restrictions. We performed four meta-analyses to estimate the pooled effect sizes using a random effect model. The outcomes were perineural, vascular and lymphatic invasion rates, and 5-year overall survival rate in patients with obstructive colon cancer, depending on the presence or absence of perineural invasion.

RESULTS

Ten studies with a total of 1273 patients were included in the meta-analysis. We found that patients in the stent group had a significantly higher risk of perineural (OR 1.98, 95% CI 1.22-3.21; p = 0.006) and lymphatic invasion (OR 1.45, 95% CI 1.10-1.90; p = 0.008). Furthermore, patients with positive perineural invasion had almost twice the risk of dying compared to those with no perineural invasion (HR 1.92, 95% CI 1.22-3.02; p = 0.005).

CONCLUSIONS

Stent placement as a bridge to surgery in colorectal cancer patients modifies the pathological characteristics such as perineural and lymphatic invasion, and this may worsen the long-term prognosis of patients. The presence of perineural infiltration in obstructed colon cancer decreases the long-term survival of patients.