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Background: After resection of colorectal cancer liver metastases (CRLM), 2 main histopathological growth patterns can be observed: a desmoplastic and a nondesmoplastic subtype. The desmoplastic subtype has been associated with superior survival. These findings require external validation., Methods: An international multicenter retrospective cohort study was conducted in patients treated surgically for CRLM at 3 tertiary hospitals in the United States and the Netherlands. Determination of histopathological growth patterns was performed on hematoxylin and eosin-stained sections of resected CRLM according to international guidelines. Patients displaying a desmoplastic histopathological phenotype (only desmoplastic growth observed) were compared with patients with a nondesmoplastic phenotype (any nondesmoplastic growth observed). Cutoff analyses on the extent of nondesmoplastic growth were performed. Overall survival (OS) and disease-free survival (DFS) were estimated using Kaplan-Meier and multivariable Cox analysis. All statistical tests were 2-sided., Results: In total 780 patients were eligible. A desmoplastic phenotype was observed in 19.1% and was associated with microsatellite instability (14.6% vs 3.6%, P  = .01). Desmoplastic patients had superior 5-year OS (73.4%, 95% confidence interval [CI] = 64.1% to 84.0% vs 44.2%, 95% CI = 38.9% to 50.2%, P  < .001) and DFS (32.0%, 95% CI = 22.9% to 44.7% vs 14.7%, 95% CI = 11.7% to 18.6%, P  < .001) compared with their nondesmoplastic counterparts. A desmoplastic phenotype was associated with an adjusted hazard ratio for death of 0.36 (95% CI = 0.23 to 0.58) and 0.50 (95% CI = 0.37 to 0.66) for cancer recurrence. Prognosis was independent of KRAS and BRAF status. The cutoff analyses found no prognostic relationship between either OS or DFS and the extent of nondesmoplastic growth observed (all P  > .1)., Conclusions: This external validation study confirms the remarkably good prognosis after surgery for CRLM in patients with a desmoplastic phenotype. The extent of nondesmoplastic growth does not affect prognosis., (© The Author(s) 2021. Published by Oxford University Press.)

Background: This study investigated the effect of the reduced dose of systemic chemotherapy (SYS) on recurrence patterns in patients receiving adjuvant hepatic artery infusion (HAI) chemotherapy after complete colorectal liver metastases (CRLM) resection., Methods: Patients undergoing complete CRLM resection between 2000 and 2007 were selected from a prospectively maintained database and categorized as receiving SYS or HAI + SYS. Those with pre and/or intraoperative extrahepatic disease, documented death, or recurrence within 30 days of CRLM resection were excluded. Competing risk, Fine and Gray's tests were used to compare SYS versus HAI + SYS for time-to-organ recurrence., Results: Of 361 study patients, 153 (42.4%) received SYS and 208 (57.6%) received HAI + SYS. The median follow-up for survivors was 100 (range = 12-185) and 156 months (range = 18-217) for SYS and HAI + SYS, respectively. The 5-year cumulative incidence (CI) of any liver recurrence was greater for those receiving SYS (SYS = 41.9% vs. HAI + SYS = 28.6%, p = .005). The 5-year CI of developing any lung or extrahepatic recurrence for SYS patients was 36.2% and 47.9% compared with 44.5% (p = .242) and 51.7% (p = .551), respectively, in patients receiving HAI + SYS., Conclusion: Despite the reduced dose of SYS, adjuvant HAI + SYS after CRLM resection is not associated with a significantly increased risk of extrahepatic recurrence., (© 2020 Wiley Periodicals LLC.)