PURPOSE: Chemotherapy is established as primary treatment in patients with stage IV colorectal cancer and unresectable metastases. Data from nonrandomized clinical trials have fueled persistent uncertainty if primary tumor resection (PTR) before chemotherapy prolongs survival. We investigated the prognostic value of PTR in patients with newly diagnosed stage IV colon cancer who were not amenable to curative treatment. PATIENTS AND METHODS: Patients enrolled in the multicenter, randomized SYNCHRONOUS and CCRe-IV trials were included in the analysis. Patients with colon cancer with synchronous unresectable metastases were randomly assigned at 100 sites in Austria, Germany, and Spain to undergo PTR or up-front chemotherapy (No PTR group). The chemotherapy regimen was left at discretion of the local team. Patients with tumor-related symptoms, inability to tolerate surgery and/or systemic chemotherapy, and history of another cancer were excluded. The primary end point was overall survival (OS), and the analyses were performed with intention-to-treat. RESULTS: A total of 393 patients were randomly assigned to undergo PTR (n = 187) or no PTR (n = 206) between November 2011 and March 2017. Chemotherapy was not administered to 6.4% in the No PTR group and 24.1% in the PTR group. The median follow-up time was 36.7 months (95% CI, 36.6 to 37.3). The median OS was 16.7 months (95% CI, 13.2 to 19.2) in the PTR group and 18.6 months (95% CI, 16.2 to 22.3) in the No PTR group ( P = .191). Comparable OS between the study groups was further confirmed on multivariate analysis (hazard ratio, 0.944 [95% CI, 0.738 to 1.209], P = .65) and across all subgroups. Patients with serious adverse events were more common in the No PTR group (10.2% v 18.0%; P = .027). CONCLUSION: Among patients with colon cancer and synchronous unresectable metastases, PTR before systemic chemotherapy was not associated with prolonged OS.

Many different options of neoadjuvant treatments for advanced colon cancer are emerging. An accurate preoperative staging is crucial to select the most appropriate treatment option. A retrospective study was carried out on a national series of operated patients with T4 tumors. Considering the anatomo-pathological analysis of the surgical specimen as the gold standard, a diagnostic accuracy study was carried out on the variables T and N staging and the presence of peritoneal metastases (M1c). The parameters calculated were sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios, as well as the overall accuracy. A total of 50 centers participated in the study in which 1950 patients were analyzed. The sensitivity of CT for correct staging of T4 colon tumors was 57%. Regarding N staging, the overall accuracy was 63%, with a sensitivity of 64% and a specificity of 62%; however, the positive and negative likelihood ratios were 1.7 and 0.58, respectively. For the diagnosis of peritoneal metastases, the accuracy was 94.8%, with a sensitivity of 40% and specificity of 98%; in the case of peritoneal metastases, the positive and negative likelihood ratios were 24.4 and 0.61, respectively. The diagnostic accuracy of CT in the setting of advanced colon cancer still has some shortcomings for accurate diagnosis of stage T4, correct classification of lymph nodes, and preoperative detection of peritoneal metastases.