Abstract
BackgroundThe prognostic role of perineural invasion in gastric cancer is controversial. Here, we present a systemic review and meta-analysis of the association between perineural invasion and survival in resectable gastric cancer patients.MethodsA comprehensive literature search for relevant reports published up to April 2013 was performed using PubMed, Embase, Web of Science and Wanfang Data. Studies that investigated the role of perineural invasion with a sample size greater than 100 were included and analyzed.ResultsA total of 30,590 gastric cancer patients who had undergone curative gastrectomy from twenty-four studies were included. The median rate of perineural invasion positive was 40.9% (6.8%–75.6%). Fourteen studies investigated overall survival unadjusted for other variables in 23,233 gastric cancer patients. The relative hazard estimates ranged from 0.568–7.901 with a combined random effects estimate of 2.261 (95% CI = 1.841–2.777, P = 0.000). The effect of perineural invasion on overall survival adjusted for other prognostic factors was reported in 17 studies incorporating 8,551 cases. The hazard estimates ranged from 0.420–8.110 with a pooled random effects estimates of 1.484 (95% CI = 1.237–1.781, P = 0.000). There was heterogeneity between the studies (Q = 49.22, I-squared = 67.5%, P = 0.000). Disease-free survival was investigated adjusted in four studies incorporating 9,083 cases and the pooled fixed hazard ratio estimate was 1.371(95% CI = 1.230–1.527, P = 0.000).ConclusionPerineural invasion is an independent prognostic factor affecting overall survival and disease-free survival of gastric cancer patients who had undergone the curative resection. This effect is independent of lymph node status, tumor size and the depth of invasion as well as a range of other biological variables on multivariate analysis. Large prospective studies are now needed to establish perineural invasion as an independent prognostic marker for gastric cancer.
Highlights
Gastric cancer is the fourth most common cancer worldwide and the second leading cause of cancer-related death in Asia
We identified all published reports that assessed the relationship between Perineural invasion (PNI) and outcome in gastric cancer and performed a meta-analysis using standard statistical techniques
After reading full texts of potentially eligible articles, those which are small sized or poor quality or have no related outcome or data couldn’t be extracted were excluded and 24 studies were included in this systemic review and meta-analysis [3,4,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35](figure 1)
Summary
Gastric cancer is the fourth most common cancer worldwide and the second leading cause of cancer-related death in Asia. Most of gastric cancer patients will die of recurrence and metastasis, with 5-year overall survival no more than 50% for resectable patients in China [1]. PNI is found to be related to a more aggressive tumor phenotype and poor prognosis in several malignancies, most notably head and neck and prostate cancers. The prognostic significance of PNI had been investigated in a few studies, but they had not reached consensus. The prognostic role of perineural invasion in gastric cancer is controversial. We present a systemic review and meta-analysis of the association between perineural invasion and survival in resectable gastric cancer patients
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