borderline significanceP = 0.051
3.4 Development of a machine learning model for survival risk prognostication In a multivariate Cox proportional hazards model together with MBR and primary tumour sidedness, CRLM surface area was an independent predictor (HR 4.52, 95% CI: 1.43–14.3, P = 0.01, see Table S5 ), whereas CRLM volume showed only borderline significance (HR 3.00, 95% CI: 1.00–9.05, P = 0.051).