“…Nevertheless, not every patient will be a candidate for surgery, and among patients, the benefits of surgery will be different. Studies which performed multivariate analysis to determine which factors were associated with survival in patients with unresectable colorectal cancer, in addition to PTR, identified the following independent prognostic variables: primary tumor differentiation grade [4, 5, 11, 21–23, 25, 28, 29, 48], number of metastatic sites [2, 12, 14, 18, 21, 22, 25, 47, 66], primary tumor location [4, 6, 12, 22, 23, 25, 28, 66], extent of metastatic liver involvement [32, 48, 49, 75, 81, 89, 94], administration of chemotherapy [4, 14, 20, 24, 32, 39, 48, 49, 93], administration of anti‐VEGF therapy [2, 13, 21, 23], CEA levels [5, 12–14, 28, 32], age [4, 6, 18, 22, 25, 28, 29], Eastern Cooperative Oncology Group performance status (ECOG‐PS) [4, 14, …”