Primary Tumor-Related Complications and Salvage Outcomes in Patients with Metastatic Rectal Cancer and an Untreated Primary Tumor

BACKGROUND: For rectal cancer with unresectable metastases, current practice favors omitting interventions directed at the primary tumor in asymptomatic patients. OBJECTIVE: This study aimed to determine the proportion of patients with primary tumor-related complications, characterize salvage outcomes, and measure survival in patients with metastatic rectal cancer who did not undergo upfront intervention for their primary tumor. DESIGN: This is a retrospective analysis. SETTING: This study was conducted at a comprehensive cancer center. PATIENTS: Patients who presented between January 1, 2008, and December 31, 2015, with synchronous stage IV rectal cancer, an unresected primary tumor, and no prior primary tumor-directed intervention were selected. MAIN OUTCOME MEASURES: The main outcome measured was the rate of primary tumor-related complications in the cohort that did not receive any primary tumor-directed intervention. The Kaplan-Meier method and Cox regression analysis were used to determine whether complications are associated with survival. RESULTS: The cohort comprised 358 patients with a median age of 56 years (22-92). Median follow-up was 26 months (range, 1-93 months). Among the 168 patients (46.9%) who eventually underwent elective resection of the primary tumor, the surgery was performed with curative intent in 66 patients (18.4%) and preemptive intent in 102 patients (28.5%). Of the 190 patients who did not undergo an upfront or elective intervention for the primary tumor, 68 (35.8%) experienced complications. Nonsurgical intervention for complications was attempted in 34 patients with an overall success rate of 61.8% (21/34). Surgical intervention was performed in 47 patients (including 13 patients for whom nonsurgical intervention failed): diversion in 26 patients and resection in 21 patients. Of those 47 patients, 42 (89.4%) ended up with a colostomy or ileostomy. LIMITATIONS: This study was conducted at a single center. CONCLUSION: A significant proportion of patients with metastatic rectal cancer and untreated primary tumor experience primary tumor-related complications. These patients should be followed closely, and preemptive intervention (resection, diversion, or radiation) should be considered if the primary tumor progresses despite systemic therapy.