Angiopoietin-2 predicts prognosis in lung cancer
Serum concentrations of angiopoietin-2 (Ang-2) appear to predict the tumour staging and prognosis of patients with lung cancer, according to a new systematic review and meta-analysis.
After the selection criteria were applied, 20 studies, corresponding to 1,911 patients, were eligible for inclusion. Of these, the nine that evaluated the relationship between Ang-2 levels and disease progression showed a positive significant association between serum Ang-2 levels and tumour stage.
Specifically, a significant difference in Ang-2 levels was observed between stage 1 tumours and stages 2 (standardized mean difference [SMD], -0.51; 95 percent CI, -0.75 to -0.27; p<0.001), 3 (SMD, -0.83; -1.44 to -0.21; p=0.009) and 4 (SMD, -1.51; -2.59 to -0.42; p=0.006) tumours.
Ang-2 serum levels were also significantly different between stage 2 tumours and stages 3 (SMD, -0.52; -0.80 to -0.244; p<0.001) and 4 (SMD, -1.21; -1.98 to -0.44; p=0.002) tumours. Stages 3 and 4 tumours also differ in Ang-2 levels (SMD, -0.58; -0.93 to -0.23; p=0.001).
Serum Ang-2 concentrations were also significantly higher in lung cancer patients with lymph node involvement (SMD, 1.06; 0.57 to 1.56; p<0.001).
The role of Ang-2 on disease prognosis was examined in seven studies which included 575 patients. In these, significantly worse prognosis was associated with high serum Ang-2 levels (hazard ratio [HR], 1.64; 1.20 to 2.25; p=0.002).
Subgroup analysis by type of lung cancer showed that elevated Ang-2 levels were a risk factor for poor prognosis in patients with non-small cell lung cancer (HR, 1.44; 1.07 to 1.93; p=0.017) and small cell lung cancer (HR, 2.29; 1.46 to 3.59; p<0.001).