BACKGROUND:Patients with surgically resectable BRAF-mutated colorectal liver metastases (CRLM) or limited extrahepatic disease constitute a highly selective subgroup among BRAF-mutated patients, characterized by a more indolent disease biology. This is evident in their suitability for surgical resection. However, initial studies from a decade ago presented a discouraging outlook for these patients, citing early, frequent, multifocal recurrences and a very limited median overall survival (OS) of less than two years. Our objective was to provide an updated, comprehensive, and critically assessed review of the current literature on the prognostic impact of BRAF variants in CRLM, as well as to explore optimal treatment strategies for these patients through a systematic search. METHODS:A systematic literature search of the Medline, Scopus, and CENTRAL databases for studies reporting long-term outcomes of patients with a known BRAF status was performed. RESULTS:A total of 386 unique studies were screened during the study selection process. After applying the exclusion criteria, a total of 18 studies published between 2012 and 2023 were deemed eligible for inclusion. CONCLUSIONS:In contrast to older studies, more recent studies, with larger sample sizes, have revealed that the rate of extrahepatic recurrence is comparable between BRAF-mutated and wild-type patients. Furthermore, they have reported significantly improved survival outcomes, with OS extending up to 52 months. Notably, patients with non-V600E BRAF mutations may even achieve outcomes comparable to those with wild-type BRAF CRLM. Additionally, a few recent studies have compared surgery and systemic therapies, indicating that surgery is associated with improved survival rates, even for patients with the V600E mutation. This challenges the previous belief that BRAF mutations are absolute contraindications to surgical treatment. Surgical denial for technically resectable patients may now be reserved for specific clinical scenarios, such as the presence of a BRAF V600E mutation and concurrent extrahepatic disease.

BACKGROUND:The prognostic implication of mutant KRAS (mKRAS) among patients with primary disease in the rectum remains unknown.METHODS:From 2000 to 2018, patients undergoing hepatectomy for colorectal liver metastases at 10 collaborating international institutions with documented KRAS status were surveyed.RESULTS:A total of 834 (65.8%) patients with primary colon cancer and 434 (34.2%) patients with primary rectal cancer were included. In patients with primary colon cancer, mKRAS served as a reliable prognostic biomarker of poor overall survival (OS) (hazard ratio [HR]: 1.58, 95% CI 1.28-1.95) in the multivariable analysis. Although a trend towards significance was noted, mKRAS was not found to be an independent predictor of OS in patients with primary rectal tumors (HR 1.34, 95% CI 0.98-1.80). For colon cancer, the specific codon impacted in mKRAS appears to reflect underlying disease biology and oncologic outcomes, with codon 13 being associated with particularly poor OS in patients with left-sided tumors (codon 12, HR 1.56, 95% CI 1.22-1.99; codon 13, HR 2.10 95% CI 1.43-3.08;). Stratifying the rectal patient population by codon mutation did not confer prognostic significance following hepatectomy.CONCLUSIONS:While the left-sided colonic disease is frequently grouped with rectal disease, our analysis suggests that there exist fundamental biologic differences that drive disparate outcomes. Although there was a trend toward significance of KRAS mutations for patients with primary rectal cancers, it failed to achieve statistical significance.

Two novel clinical risk scores (CRS) that incorporate KRAS mutation status were developed: modified CRS (mCRS) and GAME score. However, they have not been tested in large national and international cohorts. The aim of this study was to validate the prognostic discrimination utility and determine the clinical usefulness of the two novel CRS.

Despite the long‐standing consensus on the importance of tumor size, tumor number and carcinoembryonic antigen (CEA) levels as predictors of long‐term outcomes among patients with colorectal liver metastases (CRLM), optimal prognostic cut‐offs for these variables have not been established.

BACKGROUND/AIM:Several studies have found elevated soluble CD40 Ligand (sCD40L) in the serum of patients with malignancies as well as those with inflammatory bowel disease (IBD). Our goal was to determine the possible causal role of sCD40L in colitis-associated colorectal cancer (CAC) by using the well-established azoxymethane/dextran sulfate sodium (AOM/DSS) protocol.MATERIALS AND METHODS:Twelve wild type (WT) and twelve TLR4 knock out (KO) female C57BL6 mice were divided into 4 experimental groups. Six WT and six TLR4 KO mice were treated with a single intraperitoneal dose (10 mg/kg of body weight) of AOM followed by three 7-day cycles of oral 2.5% DSS. The other two groups included 6 WT and 6 TLR4 KO mice that received only water and served as the control groups. The mice were sacrificed after 84 days.RESULTS:All mice in the AOM/DSS WT group developed CAC while all mice from the AOM/DSS TLR4 KO group were protected from CAC. We measured the serum and pathologic tissue levels of sCD40L with quantitative sandwich enzyme-linked immunoassay (ELISA) and found that serum sCD40L was significantly higher in wild-type mice that developed CAC compared to their healthy counterparts (wild-type and TLR-4 KO controls). In comparison, serum sCD40L levels were comparable between TLR-4 KO mice, which are protected from developing CAC, and their healthy counterparts (wild-type and TLR-4 KO controls). Of note, tissue levels of sCD40L were not affected by the development of CAC.CONCLUSION:Our findings point to the presence of an axis between TLR-4 and sCD40L, which may lead to decreased immunosurveillance and the subsequent development of colitis-associated cancer.

Pancreatic ductal adenocarcinoma (PDAC) represents one of the most aggressive malignancies, and the majority of patients with PDAC present with metastatic disease, mainly in the liver, at the time of diagnosis. Surgical resection is the only treatment that can offer prolonged survival and possible cure. However, the indications for surgery for patients with PDAC metastases remain extremely limited to highly selected patients with localized disease, and metastatic disease is generally regarded as a contraindication to surgery. Recently, however, the advent of more effective chemotherapy has changed the treatment strategy for metastatic PDAC. In fact, cases in which resection of synchronous or metachronous PDAC liver metastases lead to prolonged survival in highly selected patients have been reported. In this review, we provide current data regarding survival outcomes after surgery, and discuss the role of surgical resection and selection criteria for patients with PDAC liver metastases in the modern era.

BACKGROUND:Although the prognostic relevance of KRAS status in metastatic colorectal cancer (CRC) depends on tumor laterality, this relationship is largely unknown in non-metastatic CRC. METHODS:Patients who underwent resection for non-metastatic CRC between 2000 and 2018 were identified from institutional databases at six academic tertiary centers in Europe and Japan. The prognostic relevance of KRAS status in patients with right-sided (RS), left-sided (LS), and rectal cancers was assessed. RESULTS:Of the 1093 eligible patients, 378 had right-sided tumors and 715 had left-sided tumors. Among patients with RS tumors, the 5-year overall (OS) and recurrence-free survival (RFS) for patients with KRASmut versus wild-type tumors was not shown to differ significantly (82.2% vs. 83.2% and 72.1% vs. 76.7%, respectively, all p > .05). Among those with LS tumors, KRAS mutation was associated with shorter 5-year OS and RFS on both the univariable (OS: 79.4% vs. 86.1%, p = .004; RFS: 68.8% vs. 77.3%, p = .005) and multivariable analysis (OS: HR: 1.52, p = .019; RFS: HR: 1.32, p = .05). CONCLUSIONS:KRAS mutation status was independently prognostic among patients with LS tumors, but this association failed to reach statistical significance in RS and rectal tumors. These findings confirm reports in metastatic CRC and underline the possible biologic importance of tumor location.

OBJECTIVE:To examine the prognostic impact of tumor laterality in colon cancer liver metastases (CLM) after stratifying by Kirsten rat sarcoma 2 viral oncogene homolog (KRAS) mutational status.BACKGROUND:Although some studies have demonstrated that patients with CLM from a right sided (RS) primary cancer fare worse, others have found equivocal outcomes of patients with CLM with RS versus left-sided (LS) primary tumors. Importantly, recent evidence from unresectable metastatic CRC suggests that tumor laterality impacts prognosis only in those with wild-type tumors.METHODS:Patients with rectal or transverse colon tumors and those with unknown KRAS mutational status were excluded from analysis. The prognostic impact of RS versus LS primary CRC was determined after stratifying by KRAS mutational status.RESULTS:277 patients had a RS (38.6%) and 441 (61.4%) had a LS tumor. Approximately one-third of tumors (28.1%) harbored KRAS mutations. In the entire cohort, RS was associated with worse 5-year overall survival (OS) compared with LS (39.4% vs 50.8%, P = 0.03) and remained significantly associated with worse OS in the multivariable analysis (hazard ratio 1.45, P = 0.04). In wild-type patients, a worse 5-year OS associated with a RS tumor was evident in univariable analysis (43.7% vs 55.5%, P = 0.02) and persisted in multivariable analysis (hazard ratio 1.49, P = 0.01). In contrast, among patients with KRAS mutated tumors, tumor laterality had no impact on 5-year OS, even in the univariable analysis (32.8% vs 34.0%, P = 0.38).CONCLUSIONS:This study demonstrated, for the first time, that the prognostic impact of primary tumor side differs according to KRAS mutational status. RS tumors were associated with worse survival only in patients with wild-type tumors.

BACKGROUND:While previously believed to be mutually exclusive, concomitant mutation of Kirsten rat sarcoma viral oncogene homolog (KRAS)- and V-raf murine sarcoma b-viral oncogene homolog B1 (BRAF)-mutated colorectal carcinoma (CRC), has been described in rare instances and been associated with advanced-stage disease. The present case series is the first to report on the implications of concurrent KRAS/BRAF mutations among surgically treated patients, and the largest set of patients with surgically treated colorectal liver metastasis (CRLM) and data on KRAS/BRAF mutational status thus far described.CASE SERIES:We present cases from an international, multi-institutional cohort of patients that underwent hepatic resection for CRLM between 2000-2015 at seven tertiary centers. The incidence of KRAS/BRAF mutation in patients with CRLM was 0.5% (4/820). Of these cases, patient 1 (T2N1 primary, G13D/V600E), patient 2 (T3N1 primary, G12V/V600E) and patient 3 (T4N2 primary, G13D/D594N) succumbed to their disease within 485, 236 and 79 days respectively, post-hepatic resection. Patient 4 (T4 primary, G12S/G469S) was alive 416 days after hepatic resection.CONCLUSION:The present case series suggests that the incidence of concomitant KRAS/BRAF mutations in surgical cohorts may be higher than previously hypothesized, and associated with more variable survival outcomes than expected.

Objective: To examine the impact of surgical margin width on survival following R0 hepatic resection for colorectal metastases (CRLM). Summary of Background Data:Although negative resection margin is considered of paramount importance for the prognosis of patients with colorectal liver metastases, optimal resection margin width remains controversial. Methods: Eligible studies examining the association between margin status after R0 hepatic resection for CRLM and survival, including overall survival (OS) and disease-free survival (DFS) were sought using the Medline, Cochrane, and EMBASE databases. Random-effects models were used for the calculation of pooled relative risks (RRs) with their 95% confidence intervals (95% CIs). Results: Thirty-four studies were deemed eligible for inclusion representing a cohort of 11,147 hepatic resections. Wider resection margin (>1 vs <1cm) was significantly associated with improved OS at 3 years (pooled RR = 0.86, 95% CI: 0.79-0.95), 5 years (pooled RR = 0.91, 95% CI: 0.85-0.97), and 10 years (pooled RR = 0.94, 95% CI: 0.88-1.00). Similarly, DFS was positively associated with >1cm resection margin at 3, 5, and 10 years. Interestingly, >1mm (vs <1mm) resection margin was significantly associated with improved OS at all-time points. Meta-regression analyses did not reveal any significant modifying role of the study features under investigation, such as the administration of neoadjuvant/adjuvant therapy. Conclusions: Importantly, our findings suggest that while a >1mm margin is associated with better prognosis than a submillimeter margin, achieving a margin >1cm may result in even better oncologic outcomes and should be considered if possible.

Background/Aim: Radiofrequency ablation (RFA) is thought to result in inferior prognosis than hepatic resection among patients with colorectal liver metastasis (CRLM). However, resection plus RFA may be an option for patients with a large number of tumors (≥4 liver lesions) and borderline resectability. Materials and Methods: A total of 717 patients with CRLM who underwent hepatic resection +/− RFA at two tertiary institutions between 09/01/2000-12/01/2015 were eligible for inclusion in this study. Results: Among patients with <4 lesions (n=568), OS in the resection + RFA group (n=48) was significantly worse than in the resection alone group (n=520) (5-year OS: 34.4 % versus 58.9%, p=0.007). Conversely, in patients with ≥4 lesions, OS in the resection + RFA (n=68) and resection alone(n=81) groups were not significantly different (5-year OS: 31.9% versus 34.1%, p=0.48). In patients with <4 lesions, carcinoembryonic antigen (CEA) ≥30 ng/ml, extrahepatic metastasis, preoperative chemotherapy and resection + RFA were independently associated with poor prognosis. Interestingly, in patients with ≥4 lesions, positive primary lymph nodes, KRAS mutation, CEA ≥30 ng/ml and extrahepatic metastasis were independent predictors of poor prognosis; however, the combination of hepatic resection with RFA was not associated with worse survival (p=0.93). Conclusion: Although surgeons should always strive for R0 resection when feasible, combined resection and RFA may be a viable alternative for CRLM patients with a large number of tumors.

Georgios A. Margonis, MD, PhD, Theodoros N. Sergentanis, MD, PhD,y Ioannis Ntanasis-Stathopoulos, MD,y Nikolaos Andreatos, MD, Ioannis-Georgios Tzanninis, MD,y Kazunari Sasaki, MD, Theodora Psaltopoulou, MD, PhD,y Jaeyun Wang, BA, Stefan Buettner, MD, Apostolos E. Papalois, PhD, KGSJ, AMACS,z Jin He, MD, PhD, Christopher L. Wolfgang, MD, PhD, Timothy M. Pawlik, MD, MPH, PhD,§ and Matthew J. Weiss, MD

PURPOSETumor location (right-sided vs. left-sided) is known to exert a significant influence on the prognosis of primary colorectal cancer (CRC). Given the genetic continuity between primary and metastatic lesions, we aimed to summarize the existing literature on the prognostic implications of primary tumor site as well as to examine the response to chemotherapy by primary tumor location in patients with metastatic CRC (mCRC).METHODSA structured review of the literature was performed between 6/1/2016-7/1/2016 using the Pubmed database. Original research articles published between 1/1/2000- 07/01/2016 were considered eligible. The primary endpoints were overall survival (OS)/ progression free survival (PFS) and response to systemic treatment in patients with mCRC.RESULTSEleven studies were included. Tumor site was a strong independent predictor of worse OS/PFS in 9 studies, with right-sided tumors having worse prognosis in all cases. Furthermore, 6 studies demonstrated an inferior response to systemic treatment or worse prognosis following the administration of specific regimens among patients with right-sided cancers. As such, there is significant evidence that right-sided lesions are associated with poor outcomes and resistance to systemic treatment.CONCLUSIONConsequently, primary tumor location should be a consideration, when the administration of systemic therapy is contemplated in mCRC.

Background. Although the prognostic role of surgical margin status after resection of colorectal liver metastasis (CRLM) has been previously examined, controversy still surrounds the importance of surgical margin status in patients with multiple tumors.Methods. Patients who underwent curative-intent surgery for CRLM from 2000 to 2015 and who presented with multiple tumors were identified. Patients with R1 resection status determined by the closest resection margin of the non-largest tumor were classified as R1-Type 1; patients with R1 status determined by the resection margin of the largest tumor were defined as R1-Type 2. Data regarding surgical margin status, size of tumors, and overall survival (OS) were collected and assessed.Results. A total of 251 patients met inclusion criteria; 156 patients (62.2%) had a negative margin (R0), 50 had an R1-type 1 (19.9%), and 45 had an R1-type 2 (17.9%) margin. Median and 5-year OS in the entire cohort was 56.4 months and 48.0%, respectively. When all R1 (Type 1 + Type 2) patients were compared with R0 patients, an R1 was not associated with worse prognosis (P = 0.05). In contrast, when R1-type 2 patients were compared with R0 patients, an R1 was strongly associated with worse OS (P = 0.009). On multivariate analysis, although the prognostic impact of all R1 was not associated with OS (hazard ratio [HR] 1.56; P = 0.08), R1-Type 2 margin status independently predicted a poor outcome (HR 1.93; P = 0.03).Conclusions. The impact of margin status varied according to the size of the tumor assessed. While R1 margin status defined according to the non-largest tumor was not associated with OS, R1 margin status relative to the largest index lesion was associated with prognosis.

BACKGROUND:Recently, a tumor-burden "metro ticket" score (TBS) based on final pathology was proposed to predict outcome following resection of colorectal liver metastasis (CRLM). We sought to validate the TBS prognostic tool using preoperative radiologic cross-sectional imaging. METHODS:Imaging TBS was defined on a Cartesian plane that incorporated both maximum tumor size (x-axis) and lesion number (y-axis) assessed by pre-operative imaging. The discriminatory power (area under the curve [AUC]) and goodness-of-fit (Harrel's C statistic and Somer's D statistics) of the imaging TBS model was assessed. RESULTS:Imaging and pathologic TBS correlated strongly (r = 0.76, P < 0.01). Among patients treated with neoadjuvant therapy, the correlation was strongest among patients with progressive disease/stable disease (PD/SD) (r = 0.81). Discriminatory power of the imaging-based versus pathology-based TBS models were comparable (AUC 0.64 vs. 0.67, respectively P > 0.05). An incremental worsening of long-term survival was noted as the imaging TBS increased (5-year OS: Zone1, Zone2, and Zone3-61.3%, 46.7%, and 38.5%, respectively; P = 0.03). The imaging-based TBS model outperformed the "classic" pathology-based Fong score (Harrel's C-index: imaging TBS-0.56 vs. Fong score-0.53; Somers'D-index: imaging TBS-012 vs. Fong score-0.06). CONCLUSIONS:Imaging-based TBS was superior to traditional tumor size and number and was comparable to pathology-based TBS. Imaging-based TBS may have the potential to facilitate improved preoperative risk stratification of patients with CRLM.