Hepatoid adenocarcinoma of the lung: An analysis of the Surveillance, Epidemiology, and End Results (SEER) database.

Hepatoid adenocarcinoma of the lung (HAL) is a rare malignant tumor that is defined as a primary alpha-fetoprotein (AFP)-producing lung carcinoma. We aimed to identify prognostic factors associated with the survival of patients with HAL using data from the Surveillance, Epidemiology, and End Results (SEER) database. We collected data from patients diagnosed with HAL, adenocarcinoma (ADC), and squamous cell carcinoma (SCC) of the lung between 1975 and 2016 from the SEER database. The clinical features of patients with ADC and SCC of the lung were also analyzed. The clinical features of HALs were compared to ADCs and SCCs. A chi-square test was used to calculate the correlations between categorical variables, and a t test or Mann-Whitney U test was used for continuous variables. The Kaplan-Meier method and Cox regression analysis were used to identify the prognostic factors for the overall survival (OS) of HALs. Two-tailed p values < 0.05 were considered statistically significant. Sixty-five patients with HAL, 2,84,379 patients with ADC, and 1,86,494 with SCC were identified from the SEER database. Fewer males, advanced stages, and more chemotherapy-treated HALs were found. Compared to patients with SCC, patients with HAL were less likely to be male, more likely to be in an advanced stage, and more likely to receive chemotherapy (p < 0.05). The American Joint Committee on Cancer staging was the only prognostic factor for OS in patients with HAL, and stage IV was significantly different from other stages (hazard ratio = 0.045, 95% confidence interval: 0.005-0.398, p = 0.005). Males with HAL were more likely to receive radiotherapy compared to females with HAL (61.8 vs 31.5%, p = 0.034). Younger patients with HAL were more likely to receive chemotherapy (59.4 + 10.2 years vs 69 + 11.3 years, p = 0.001). The primary tumor size of HAL was associated with the location of the primary lesion (p = 0.012). No conventional antitumor therapies, including surgery, chemotherapy, and radiotherapy, were shown to have a significant survival benefit in patients with HAL (p > 0.05). This study showed that stage IV was the only prognostic factor for OS in HALs compared to other clinicopathologic factors. Conventional antitumor therapies failed to show survival benefit; thus, a more effective method by which to treat HAL is needed. Interestingly, the clinical features and the location of the primary lesion were shown to be associated with primary tumor size and treatment in patients with HAL, which have not been reported before.