Models for Predicting Early Death in Patients With Stage IV Esophageal Cancer: A Surveillance, Epidemiology, and End Results-Based Cohort Study

Background

Despite enormous progress in the stage IV esophageal cancer (EC) treatment, some patients experience early death after diagnosis. This study aimed to identify the early death risk factors and construct models for predicting early death in stage IV EC patients.

Methods

Stage IV EC patients diagnosed between 2010 and 2015 in the Surveillance, Epidemiology, and End Results (SEER) database were selected. Early death was defined as death within 3 months of diagnosis, with or without therapy. Early death risk factors were identified using logistic regression analyses and further used to construct predictive models. The concordance index (C-index), calibration curves, and decision curve analyses (DCA) were used to assess model performance.

Results

Out of 4411 patients enrolled, 1779 died within 3 months. Histologic grade, therapy, the status of the bone, liver, brain and lung metastasis, marriage, and insurance were independent factors for early death in stage IV EC patients. Histologic grade and the status of the bone and liver metastases were independent factors for early death in both chemoradiotherapy and untreated groups. Based on these variables, predictive models were constructed. The C-index was .613 (95% confidence interval (CI), [.573–.653]) and .635 (95% CI, [.596–.674]) in the chemoradiotherapy and untreated groups, respectively, while calibration curves and DCA showed moderate performance.

Conclusions

More than 40% of stage IV EC patients suffered from an early death. The models could help clinicians discriminate between low and high risks of early death and strategize individually-tailed therapeutic interventions in stage IV EC patients.

[Distribution characteristic of soil organic carbon pool in the plow layer of sloping farmland with different cultivation years in black soil region]

Tillage and erosion simultaneously cause soil movement from the top-slope position to the foot-slope position in a sloping farmland, with consequences on variation of soil organic carbon (SOC) content as well as its stability mechanism. To identify the accumulation-loss characteristics of organic carbon pool (OCP) of black soil under long-term cultivation, the distribution characteristics of different OCPs (free unprotected, physical protection, chemical protection, biochemical protection) of sloping farmland with different years of cultivation were quantified by Stewart physical-chemical fractionation method. The results showed that long-term cultivation and associated erosion resulted in significant accumulation of SOC in the foot-slope deposition area. The contents of four OCPs in the foot deposition area were significantly higher than those in top-slope eroded areas. SOC of sloping farmland was dominated by chemically protected carbon and biochemically protected carbon (＞90%). Furthermore, the top-slope erosion areas and foot-slope deposition areas mainly accumulated chemically protected organic carbon (84.6%) and biochemically protected organic carbon (51.4%), respectively. With the increases of cultivation years, the accumulation rate of four OCPs increased with the stability degree of SOC, that is, biochemical protection carbon pool (48%) ＞ chemical protection carbon pool (42.2%) ＞ physical protection carbon pool (6.4%) ＞ free unprotected carbon pool (3.4%). The proportion and accumulation rate of the free unprotected organic carbon pool were the smallest, but they were most sensitive to external interference. Thus, more attention should be paid to free unprotected organic carbon during the management of black soil.