Background: The management of asymptomatic primary tumor in patients with unresectable metastatic colorectal cancer remains inconsistent.
Objective: This study aimed to determine the rate of symptom-directed surgery after systemic chemotherapy and to estimate the impact of initial primary tumor resection on survival in patients with unresectable metastatic colorectal cancer and an asymptomatic primary tumor.
Design: This was a single-institution, retrospective observational study.
Settings: The study was conducted in a tertiary referral hospital.
Patients: Between 2005 and 2011, 191 consecutive patients with newly diagnosed stage IV colorectal cancer were identified. Of the 191, we analyzed 94 patients with unresectable, asymptomatic colorectal cancer.
Main outcome measures: We measured symptom-directed surgery and overall survival.
Results: Forty-seven patients with an intact primary tumor received systemic chemotherapy (upfront chemotherapy group), 41 underwent primary tumor resection (upfront primary tumor resection group), and 6 underwent diversion enterostomy as first-line therapy. After excluding the 6 patients undergoing diversion enterostomy before systemic chemotherapy, this left 88 patients for final analysis. Twelve upfront chemotherapy patients required symptom-directed late surgery. Overall, 1-year and 2-year rates of symptom-directed surgery were 19.1% and 26.1%. In patients with nontraversable lesions by colonoscope at diagnosis, 64.3% required late intervention within 1 year. Competing risk regression analysis revealed that only colonoscopic traversability at diagnosis was significantly associated with symptom-directed late surgery (subhazard ratio, 7.9; p = 0.004). Median overall survival time was comparable between the 2 groups at 23.9 months for the upfront primary tumor resection group and 22.6 months for the upfront chemotherapy group (HR, 0.84; 95% CI: 0.51-1.39).
Limitations: This study was limited by its retrospective nature and small sample size.
Conclusions: Approximately 75% of upfront chemotherapy patients with unresectable, asymptomatic stage IV colorectal cancer can be spared initial resection of the primary tumor. Colonoscopic findings of nontraversable lesions at diagnosis may predict the need for late surgical intervention.