Clinicopathological Characteristics and Prognosis of Hepatoid Adenocarcinoma of the Stomach: Evaluation of a Pooled Case Series.

Hepatoid adenocarcinoma of the stomach (HAS) is an extremely rare and unique gastric malignancy. The present study aimed to examine the relevance of the clinicopathological characteristics of HAS with patient prognosis. We retrospectively reviewed clinical data of 34 HAS patients treated at our institution between January 2010 and December 2016, as well as 294 cases reported prior to 2017 in research databases. Among these patients, 45.6% (115/252) had lesions in the gastric antrum and 77.0% (235/305) were male. Elevated levels of serum alpha-fetoprotein (AFP) were detected in most patients (75/93, 80.6%). Vascular invasion (199/286, 69.6%), lymph node metastasis (222/283, 78.4%), and preoperative distant metastasis (121/328, 36.9%) were commonly observed. The 5-year disease-free survival (DFS) and disease-specific survival (DSS) were 20.7% and 29.2%, respectively. DFS and DSS of patients receiving neoadjuvant therapy were significantly higher than those of patients receiving postoperative adjuvant therapy [DFS: P<0.001, hazard ratio (HR)=-1.831, 95% confidence interval (CI): 0.060-0.429; DSS: P<0.001, HR=-2.185, 95% CI: 0.032-0.401]. In conclusion, HAS exhibits distinct clinicopathological characteristics and a strikingly worse prognosis when compared with common gastric cancer. Complete surgery, early pTNM stage, and adjuvant therapy may predict a more favorable prognosis. Neoadjuvant therapy is strongly recommended for patients with lymph node metastasis or/and preoperative distant metastasis.