The OS of the 34 patients was 57.9% at five years, and the
median survival duration was 77 months. By receiver operating
characteristic curve analysis, the threshold values of the
greatest diameter of the metastatic pulmonary tumor, age
at the time of diagnosis of metastatic disease, and DFI, which
predicted death with the highest sensitivity and specificity
were ≥25-mm, ≥60 years, and ≤26 months, respectively. By
single variable analysis, histology of squamous cell carcinoma
(SCC) (P = 0.005), age ≥60 years (P = 0.003), and DFI
≤26 months (P = 0.001) were associated with a poor prognosis
(Table 3). Furthermore, a ≥25-mm maximum tumor
diameter tended to be associated with a shorter survival than
a