Differences in the prognostic value of tumor size on hepatocellular cancer-specific survival stratified by gender in a SEER population-based study

Abstract

Background and objective: Tumor size is an important prognostic factor in cancers. This study aims at investigating the interaction between gender status and tumor size to evaluate cancer-specific survival (CSS) in hepatocellular carcinoma (HCC).

Methods: In this study, we searched Surveillance, Epidemiology, and End Results (SEER) population-based data and identified 38,368 patients diagnosed with HCC between 1988 and 2012. Patients diagnosed between 1998 and 2007 were distributed into a training set (n = 19279), and the rest were assigned as a SEER validation set (n = 19089). Definition of cut-off value of tumor size stratified by gender was determined by the "X-Tile" program. The five-year CSS data were found. Long-term survival outcomes and risk factors were analyzed by the Kaplan-Meier methods and the multivariable Cox regression models.

Results: There were significant differences among these different tumor size subgroups with regards to five-year CSS (p < 0.001). When applying cutoff points of 38 mm and 75 mm tumor size in men, and 38 mm and 55 mm in women, the most significant difference was observed by the X-Tile program, respectively (p < 0.001). The five-year CSS was 27.5% for women and 25.7% for men in the training set, and 33.9% for women and 31.1% for men in the validating set (p < 0.001). Further analysis showed that this significant difference existed in localized, regional, and distant-stage patients.

Conclusions: These results demonstrated that women with HCC appeared to exhibit better survival rates than men. The sex-related discrepancies should be emphasized, particularly for HCC patients with 39 to 75 mm tumors.

Keywords: Hepatocellular carcinoma; SEER; gender; prognosis; tumor size.

Figures

Figure 1.

X-tile analysis of survival data from the SEER registry. X-tile analysis was done on patient data from the SEER registry, equally divided into training and validation sets. The optimal cut-point highlighted by the black circle in the left panels (A) is shown on a histogram of the entire cohort (middle panels) (B), and a Kaplan-Meier plot (right panels) (C). P values were determined by using the cut-point defined in the training set and applying it to the validation set.

Figure 2.

Survival curves in HCC patients according to different tumor size groups. a. 0-38 mm tumors versus 39-75 mm tumors versus ≥76 mm tumors in the training set, P<0.001; 0-38 mm tumors versus 39-55 mm tumors versus ≥56 mm tumors in the training set, P<0.001; b. 0-38 mm tumors versus 39-75 mm tumors versus ≥76 mm tumors in the validation set, P<0.001; 0-38 mm tumors versus 39-55 mm tumors versus ≥56 mm tumors in the validation set, P<0.001; HCC: hepatocellular carcinoma.

Figure 3.

Survival curves in HCC patients according to different gender status. The overall survival. Males versus females in the training set, P<0.001; The cancer-specific survival. Males versus females in the training set, P=0.002; b. The overall survival. Males versus females in the validation set, P<0.001; The cancer-specific survival. Males versus females in the validation set, P<0.001. HCC: hepatocellular carcinoma.