Safety and efficacy of first-line chemotherapy in unresected metastatic colorectal cancer

Background: Primary tumor resection in patients with metastatic colorectal cancer is considered highly controversial. Historical data suggest a low risk of primary tumor-related complications in patients treated with first-line 5-fluorouracil (5-FU) chemotherapy. However, there are very limited data on the safety and efficacy of first-line combination chemotherapy in this unresected-primary population, especially in the setting of rectal cancer. Patients and Methods: We performed a single-institution retrospective study to evaluate the primary tumor-related complication rate and outcome of patients with unresected metastatic colorectal cancer treated with first-line chemotherapy. Estimation of the overall and progression-free survival distributions were done using the Kaplan-Meier method. Results: Thirty-eight patients were identified: 26 had primary colon cancers and 12 had primary rectal cancers. Thirty-one patients were treated with first-line FOLFOX (oxaliplatin/leucovorin/5-FU) with or without bevacizumab. In patients with colon tumors, only 2 (7%) required surgery, both for obstruction. In patients with rectal tumors, 3 (25%) developed progressive obstructive symptoms, and 2 developed worsening pain. Four of these patients were adequately palliated with chemoradiation; only I patient required a diverting colostomy. The median progression-free survival was 7 months, and overall survival was 17.3 months. Twenty-two patients died because of disease progression, only 3 of whom developed obstructive symptoms at the primary tumor site before death. Conclusion: First-line chemotherapy is feasible and safe in patients with unresected colon and nonirradiated rectal cancer. The rate of bowel obstruction requiring surgical intervention in this population was < 10%. These results support an approach that defers surgery in non-obstructed, noncurable patients in favor of systemic chemotherapy as initial treatment.