Abstract:
Objective To systemically analyze the clinicopathological features and prognosis of initially diagnosed gastric cancer with an elevated serum α-fetoprotein (AFP) level.
Methods The cases of 931 hospital inpatients diagnosed with gastric adenocarcinoma via endoscopic biopsy from January 2008 to December 2020 were collected; those with a serum AFP level ≥20 ng/mL were investigated further. Hematoxylin and eosin, immunohistochemical, and special staining were employed to determine their pathological features and immunophenotypes, while their clinical features and survival were analyzed.
Results Of the 931 cases of gastric adenocarcinoma, 3.9% (36/931) exhibited high serum AFP levels (range, 20.7-16, 558 ng/mL); none showed any special clinical manifestations. At the time of diagnosis, radiological examinations showed distant metastasis in 17 cases (13 to the liver) but not in the remaining 19. Cases with distant metastasis showed a significantly higher AFP level than those without (P=0.003). The 36 cases included hepatoid adenocarcinoma (16 cases), adenocarcinoma with enteroblastic differentiation (11 cases), and conventional adenocarcinoma (9 cases). Three primitive phenotypic markers -SALL4, GPC-3, and AFP- were expressed in these subtypes. Prognosis analysis demonstrated that 19 cases with versus without distant metastasis had a better overall survival (OS) rate (P=0.002). Sixteen of the 19 cases without distant metastasis were treated with curative gastrectomy. The 16 surgically treated cases had a worse disease-free survival (P=0.044) rate than the 314 cases of gastric cancer with normal serum AFP levels, while the OS rate was comparable between them (P=0.093).
Conclusions Initially diagnosed gastric cancer with an elevated serum AFP level is rare and predominantly consists of hepatoid adenocarcinoma and adenocarcinoma with enteroblastic differentiation. Approximately one-half of these cases featured distant metastasis at the time of diagnosis, which led to an unfavorable prognosis. The prognosis may be worse for cases without distant metastasis than those of gastric cancer with a normal serum AFP level.