Survival
Upon multivariable Cox regression for all causes of mortality among the entire cohort, patients with lung metastases had a shorter survival time than those without lung metastases(HR:3.05, 95% CI:2.17-4.28,P <0.001). The variables: age (HR:1.01, 95% CI: 1.29-3.67, P = 0.024), Tumor size increase (HR:1.00, 95% CI: 1.00-1.01, P <0.001), and race (African Americans) (HR:1.89, 95% CI:1.49-2.40, P <0.001) were also significantly associated with a shorter survival time. Tumors located in the pyriform sinus(HR:0.83, 95% CI:0.69-1.00, P =0.048) indicates a longer survival time. (Table 4)
Patients in the survival cohort with hypo-pharyngeal cancer with or without lung metastases at diagnosis had a 5 year follow-up. After adjusting for sex, age, primary site of tumor and tumor size, the 5 year survival probability and cumulative mortality of patients with lung metastases was 20% and 80% respectively; the patients without lung metastases had 5 year survival probabilities and cumulative mortality rates of 60% and 40%(Figure 2). These results are consistent with the results of the cox regression. African Americans had a high cumulative mortality of 60%, while white people only had a rate of 40%(Figure 3). The tumors’ primary site of patient didn’t display a significant difference in cumulative mortality (Figure 3).