Impact of multidisciplinary tumor board (MTB) discussion on the outcome of patients with liver-limited metastasis from colorectal cancer (LMCRC).

Abstract

50 Background: MTB is a valuable tool in complex cases, since they involve different medical fields aiming for a more comprehensive decision-making process. Our aims are to describe MTB decisions in complex LMCRC, to analyze decisions compliance and evaluate outcomes. Methods: This is a retrospective analysis of medical records of patients diagnosed with liver metastasis of colorectal carcinoma (LMCRC) discussed at a single center, weekly-basis MTB from January 2019 to December 2020. Descriptive statistics was used for demographic and treatment characteristics and adhesion to MTB decisions. Survival was estimated by Kaplan-Meier method and log-rank tests. Results: Out of 1033 cases discussed at MTB, 63 met the inclusion criteria. Median age was 56.5 years (range 32 – 81), 61.9% were male, ECOG was 0-1 in 96.8%. Regarding primary tumor sidedness: 81% and 19% were left and right, respectively. Synchronous metastasis was present in 69.8% and wild-type RAS was found in 52.4% and MSI-H in 4.8%. At time of MTB, 68.3% and 4.8% had realized a first or second-line chemotherapy (CT) respectively. No previous therapy was described in 19% and 7.9% had received adjuvant CT. Previous hepatic resections occurred in 20.6%. After MTB, liver resection was recommended for 44.5%. Preoperative CT followed by one or two-stage surgery for 23.8%. Non-surgical treatments were offered for 17.5% and palliative CT for 14.3%. Decisions from the MTB were implemented in 93.6%. Reason for not performing (N = 4) were: one for disease progression, one for bureaucratic restriction and two for other reasons. Median follow-up time was 17.2m. At date of analysis, 31 patients (49.2%) had relapsed or progressed and 8 had died. Restricting for patients who underwent MTB decision (N = 59), mPFS was 14.71m. In resected cases (N = 40), who were discussed at the onset of liver metastasis diagnosis (without CT in the metastatic setting) had mPFS not reached, while who were discussed after first or second-line had mPFS of 9.39m (p 0.002). R0 resections were reached in 92.5%. Evaluating the 30-day postoperative mortality, there was one death. mPFS for palliative CT was 6.83m. Conclusions: In our analysis the adherence to MTB recommendation was high (above 90%) and patients selected for surgery presented a prolonged PFS. Our data suggest that selection of patients for liver metastasis resection in a MTB discussion should occur early in the course of treatment.