Preoperative oxaliplatin-fluoropyrimidine chemotherapy can be safely administered in patients with operable colon cancer without increasing perioperative morbidity, investigators conclude based on findings of an international randomized controlled trial of neoadjuvant chemotherapy (NAC). “This chemotherapy regimen, when given preoperatively, produces marked histopathologic down-staging, fewer incomplete resections, and better 2-year disease control,” the authors conclude. “Histologic regression after NAC is a strong predictor of lower postoperative recurrence risk so has potential use as a guide for postoperative therapy. Six weeks of NAC should be considered as a treatment option for locally advanced colon cancer.”
Study participants had radiologically staged T3-4, N0-2, M0 colon cancer when they were randomly allocated to 6 weeks oxaliplatin-fluoropyrimidine preoperatively plus 18 weeks postoperatively (NAC group) or 24 weeks postoperatively (control group). Patients with RAS-wildtype tumors could be randomly assigned to receive panitumumab or not during NAC. Based on a primary endpoint of residual disease or recurrence within 2 years, the study shows: “Of 699 patients allocated to NAC, 674 (96%) started and 606 (87%) completed NAC. In total, 686 of 699 (98.1%) NAC patients and 351 of 354 (99.2%) control patients underwent surgery. Thirty patients (4.3%) allocated to NAC developed obstructive symptoms requiring expedited surgery, but there were fewer serious postoperative complications with NAC than with control. NAC produced marked T and N downstaging and histologic tumor regression (all P < .001). Resection was more often histopathologically complete: 94% (648/686) versus 89% (311/351), P < .001. Fewer NAC than control patients had residual or recurrent disease within 2 years: 16.9% (118/699) versus 21.5% (76/354), rate ratio = 0.72 (95% CI, 0.54 to 0.98), P = .037. Tumor regression correlated strongly with freedom from recurrence. Panitumumab did not enhance the benefit from NAC. Little benefit from NAC was seen in mismatch repair–deficient tumors.”