Effect of treatment sequence on survival in stage IV rectal cancer with synchronous and potentially resectable liver metastases

Background and Objectives: The optimal treatment sequence in stage IV rectal cancer (RC) with synchronous liver metastases (SLM) remains undefined. Here, we compared outcomes between patients treated with the bowel-first approach (BFA) or the liver-first approach (LFA). Methods: Consecutive patients diagnosed with stage IV RC with SLM and who underwent complete resection were included. Both groups were matched using propensity scores. Differences in postoperative outcome, local control, and long-term survival were studied. In addition, a decision analysis (DA) model was built using TreeAge Pro to define the approach that results in the highest treatment completion rate. Results: During a 12-year period, 52 patients were identified, 21 and 31 of whom underwent the BFA and the LFA, respectively. Twenty-eight patients were matched; patients treated with the BFA experienced a longer median OS (50.0 vs 33.0 months; P = .40) and higher 5-year OS (42.9% vs 28.6%). The DA defined the BFA to be superior when the failure threshold (ie, no R0 resection, treatment discontinuation regardless of cause) for colectomy is less than 28.6%. Conclusions: In stage IV rectal cancer with SLM, either the BFA or the LFA result in similar long-term outcomes. Treatment should be tailored according to clinicopathological variables