32: Conditional Survival After Hepatectomy for Colorectal Liver Metastasis: Results from the Colorectal Liver Operative Metastasis International Collaborative
Clinical Fellow Wake Forest Baptist Medical Center Winston-Salem, North Carolina, United States
Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
Participants should be aware of the following financial/non-financial relationships:
Cristian D. Valenzuela, MD: I do not have any relevant financial / non-financial relationships with any proprietary interests.
Introduction: Colorectal liver metastasis (CLM) is a common entity in colorectal cancer, and complete resection of CLM is known to improve long-term survival. However, there is limited knowledge on conditional survival (CS)—how patient outcomes change over time, as post-operative survival milestones are achieved.
Methods: A retrospective CS analysis was performed on the Colorectal Liver Operative Metastasis International Collaborative (COLOMIC) database, of 906 consecutive CLM hepatectomy cases from 2000-2018 at five institutions. CS was calculated with Bayes’ theorem and Kaplan-Meier analysis, and pairwise comparisons used the Log-Rank method. Probability of 5-year overall survival (OS) was calculated at the time of surgery, and CS after 1, 2 and 3 post-operative years. Additional CS analyses were performed stratifying for colon cancer laterality, KRAS mutation status, and presence of extrahepatic disease at time of operation.
Results: The 5-year CS for the population was 40.6%, 45.3%, 52.8% and 65.3% at 0, 1, 2, and 3 post-operative years respectively, with significant improvements in survival (p< 0.005) with patient survival each subsequent year (Fig. A, B). Although right-sided primary colon cancers were at an initial OS disadvantage, CS was not significantly different between lateralities by post-operative year 3 (Fig. C). Patients with KRAS mutations had significantly worse CS at all timepoints (p< 0.001) (Fig. D). Extrahepatic disease was a particularly poor prognostic factor for post-operative OS, and CS at all timepoints (p< 0.001) (Fig. E). Despite worse overall prognosis associated with having KRAS mutations and extrahepatic disease, CS significantly improved as each of these populations reached the 2-year mark, compared to OS at time zero (p< 0.05).
Conclusions: 5-year CS after hepatectomy for CLM improves with each passing year of survival. Although extrahepatic disease and KRAS mutations are poor prognostic factors for OS, they still demonstrate improved CS after 2 years. CS analysis allows for surgeons to provide more accurate and informed prognostic information to patients who are undergoing postoperative surveillance.
Learning Objectives:
Upon completion, participants will be able to describe conditional survival after hepatectomy for colorectal liver metastasis: how patient prognoses change over time as post-operative survival milestones are reached.
Upon completion, participants will be able to identify KRAS mutations and extrahepatic disease as poor conditional survival prognostic factors after hepatectomy for colorectal liver metastasis.
Upon completion, participants will be able to distinguish the difference between overall survival and conditional survival, when stratifying for primary colorectal cancer laterality in operative colorectal liver metastasis.
