Impact of Primary Tumor Site on Bevacizumab Efficacy in Metastatic Colorectal Cancer

Signaling pathways in colorectal cancer implications for the target therapies

Colorectal carcinoma (CRC) stands as a pressing global health issue, marked by the unbridled proliferation of immature cells influenced by multifaceted internal and external factors. Numerous studies have explored the intricate mechanisms of tumorigenesis in CRC, with a primary emphasis on signaling pathways, particularly those associated with growth factors and chemokines. However, the sheer diversity of molecular targets introduces complexity into the selection of targeted therapies, posing a significant challenge in achieving treatment precision. The quest for an effective CRC treatment is further complicated by the absence of pathological insights into the mutations or alterations occurring in tumor cells. This study reveals the transfer of signaling from the cell membrane to the nucleus, unveiling recent advancements in this crucial cellular process. By shedding light on this novel dimension, the research enhances our understanding of the molecular intricacies underlying CRC, providing a potential avenue for breakthroughs in targeted therapeutic strategies. In addition, the study comprehensively outlines the potential immune responses incited by the aberrant activation of signaling pathways, with a specific focus on immune cells, cytokines, and their collective impact on the dynamic landscape of drug development. This research not only contributes significantly to advancing CRC treatment and molecular medicine but also lays the groundwork for future breakthroughs and clinical trials, fostering optimism for improved outcomes and refined approaches in combating colorectal carcinoma.

Impact of bevacizumab on clinical outcomes and its comparison with standard chemotherapy in metastatic colorectal cancer patients: a systematic review and meta-analysis

Background

Advances in targeted therapies have expanded the treatment options for colorectal cancer (CRC), allowing for more tailored and effective approaches to managing the disease. In targeted therapy, Bevacizumab is a commonly prescribed anti-VEGF monoclonal antibody that has a direct anti-vascular impact in cancer patients. Vascular Endothelial Growth Factors (VEGFs), especially VEGF-A, are significant agents in promoting tumour angiogenesis.

Objective

To assess the impact of adding Bevacizumab to chemotherapy on progression-free survival (PFS) and overall survival (OS) in patients with metastatic colorectal cancer.

Methodology

Comprehensive searches have been performed on electronic databases such as PubMed, and Google Scholar using the following terms: colorectal cancer, adenocarcinoma, Bevacizumab, chemotherapy, and monoclonal antibody.

Results

In the meta-analysis, 16 out of the 24 included studies were analysed. In the final analysis, incorporating Bevacizumab with chеmothеrapy demonstrated favourable outcomes for OS with a hazard ratio (HR = 0.689,95%CI: 0.51-0.83, I² = 39%, p <0.01) and for PFS with a hazard ratio (HR = 0.77 95% CI: 0.60-0.96, I² = 54%, p < 0.01). The subgroup analysis of PFS, categorised by study dеsign (prospеctivе vs rеtrospеctivе), reveals that the Hazard Ratio (HR = 0.82, 95% CI: 0.62-0.97, I² = 21%, p < 0.01) and for OS with a hazard ratio (HR = 0.73, 95% CI: 0.52-0.86, I² = 17%, p < 0.01).

Conclusion

Our findings indicate that combining Bevacizumab with chemotherapy enhances clinical outcomes and results in a significant increase in PFS and OS in patients with metastatic colorectal cancer. Positive outcomes are demonstrated by a substantial 23% increase in PFS and 31% increase in OS in patients with metastatic colorectal cancer who undergo Bevacizumab in conjunction with chemotherapy.

Dichotomous colorectal cancer behaviour

Colorectal cancer (CRC) is the third most common malignant tumor and one of the deadliest cancers. At molecular level, CRC is a heterogeneous disease that could be divided in four Consensus Molecular Subtypes. Given the differences in the disease due to its anatomical location (proximal and distal colon), another classification should be considered. Here, we review the current knowledge on CRC dichotomic´s behaviour based on two different entities; right and left-sided tumors, their impact on clinical trial data, microbiota spatial composition and the interaction with the nervous system. We discuss recent advances in understanding how the spatial tumor heterogeneity influences the tumor growth, progression, and responses to current therapies.

Primary site and treatment impact in unresectable metastatic colorectal cancer

INTRODUCTION

Colorectal cancer is a heterogenous disease, with various clinical and molecular subtypes related to the primary site (left versus right colon) of the original tumour. Primary colon tumour side is both a prognostic and predictive marker in metastatic colorectal cancer.

AREAS COVERED

There is an increasing body of evidence for how primary site may impact treatment decisions in metastatic colorectal cancer. We reviewed the evidence for its prognostic and predictive value.

EXPERT OPINION

Primary site is a prognostic marker in metastatic colorectal cancer, with right colon tumours being associated with more aggressive disease behaviour and poorer outcomes. Primary site also appears to predict for outcomes to various treatments, in particular anti-EGFR antibodies. As our understanding and testing of the molecular and biological differences within colorectal cancer increases beyond primary site, this should be integrated into the current treatment algorithm to ensure an individualised patient-centred approach to care.

Comparative Analysis of First-Line FOLFOX Treatment With and Without Anti-VEGF Therapy in Metastatic Colorectal Carcinoma: A Real-World Data Study

BACKGROUND

FOLFOX (leucovorin calcium [folinic acid], fluorouracil, and oxaliplatin) combined with or without anti-VEGF therapy represents one of the primary first-line treatment options for metastatic colorectal carcinoma (mCRC). However, there is limited comparative data on the impact of anti-VEGF therapy on treatment effectiveness, survival outcomes, and tumor location.

METHODS

This retrospective, comparative study utilized data from the AIM Cancer Care Quality Program and commercially insured patients treated at medical oncology clinics in the US. We analyzed 1652 mCRC patients who received FOLFOX, of which 1015 (61.4%) were also treated with anti-VEGF therapy (VEGF cohort).

RESULTS

Patients in the VEGF cohort exhibited a higher frequency of lung (33% vs 23%; P < .001) and liver metastases (74% vs 62%; P < .001), underwent fewer liver surgeries prior to treatment (1.2% vs 3.6%; P = .002), and had a higher proportion of right-sided tumors (27% vs 18%; P = .001). Adjusted analysis revealed no significant difference in overall survival (OS) between patients treated with and without anti-VEGF (median survival: 25.4 vs 26.0 months; P = .4). FOLFOX-only treated patients experienced higher rates of post-treatment hospitalizations (22% vs 15%; P < .001). Notably, left-sided tumors treated with anti-VEGF showed a trend toward decreased OS (median survival: 26.8 vs 33 months; P = .09).

CONCLUSION

Our real-world data analysis suggests that the addition of anti-VEGF to FOLFOX offers limited and short-lived benefits in the context of mCRC and may provide differential survival benefit based on tumor sidedness.

Nomograms predicting cancer-specific survival for stage IV colorectal cancer with synchronous lung metastases

This study aimed to establish a nomogram for the prediction of cancer-specific survival (CSS) of CRC patients with synchronous LM. The final prognostic nomogram based on prognostic factors was evaluated by concordance index (C-index), time-dependent receiver operating characteristic curves, and calibration curves. In the training and validation groups, the C-index for the nomogram was 0.648 and 0.638, and the AUC was 0.793 and 0.785, respectively. The high quality of the calibration curves in the nomogram models for CSS at 1-, 3-, and 5-year was observed. The nomogram model provided a conventional and useful tool to evaluate the 1-, 3-, and 5-year CSS of CRC patients with synchronous LM.

Evaluating the value of tumor length times width in colorectal adenocarcinoma with different tumor locations

The T classification, which reflects the vertical growth pattern of the tumor, is one of the most important prognostic factors in colorectal cancer. We aimed to investigate the prognostic value of tumor length and width in patients with colorectal cancer (CRC). A total of 259 patients with stage I-III CRC who underwent curative resection were reevaluated according to tumor location. One-way ANOVA analysis was conducted to investigate the relationship between the tumor length times width (TLTW) and clinical parameters. Univariate and multivariate analyses were conducted to analyze the potential prognostic factors affecting overall survival (OS) of patients with stage I-III CRC. In the entire cohort, the TLTW was analyzed as a continuous variable. The results suggested that TLTW (P = .003) and tumor location (P = .04) could be independent prognostic factors for patients with CRC. In addition, TLTW had an intimate relationship with tumor location (P < 0.001) and differentiation (P = .003). The mean TLTW of the right colon was significantly larger than mean TLTW of the left colon and rectal cancers. However, the mean TLTW of the left colon cancer was similar to that of the rectal cancer TLTW (P > 0.05, not shown). Subgroup analysis of TLTW according to tumor location suggested that TLTW was an independent prognostic factor for patients with right colon cancer (RCC) (P = .007) rather than left colon cancer (LCC) (P = .49) or rectal cancer (P = .16). Kaplan-Meier (K-M) analysis based on tumor location suggested that the survival rate of RCC patients had a distinctly higher trend rate than LCC patients and RECC patients in the long-term rather than in the short-term. TLTW is closely associated with tumor location in CRC. In addition, TLTW may be an independent prognostic factor for patients with RCC.

Platelet to lymphocyte ratio is associated with tumor localization and outcomes in metastatic colorectal cancer

The aim of this study was to investigate the predictive and prognostic value of PLR, and the relationship between PLR and tumor localization.A total of 229 patients with de-novo metastatic CRC were retrospectively analyzed. The cutoff value for PLR was defined by the receiver operating characteristic (ROC) curve analysis and threshold value of 196.5 as best cut-off value was found.The higher rate of BRAF mutation was significantly detected for patients with PLRhigh (> 196.5) compared to those with PLRlow (≤196.5) (P = .001). PLR was significantly higher in tumors located on the right colon (P = .012). PLR, tumor localization, the presence of surgery for primary tumor, the presence of curative surgery, the presence of metastasectomy for progression-free survival (PFS) and PLR, gender, BRAF mutation, tumor localization, the presence of surgery for primary tumor, the presence of metastasectomy for overall survival (OS) were found to be prognostic factors by univariate analysis. Multivariate analysis showed that PLR, the presence of curative surgery and the presence of metastasectomy for both PFS and OS were found to be independent prognostic factors. Moreover, a logistic regression analysis indicated that PLR and tumor localization were found to be an independent factors for predicting response to systemic treatment (P < .001 and P = .023 respectively).Our results showed that pretreatment PLR was readily feasible and simple biomarker predicting response to treatment and survival, in addition it was significantly associated with tumor localization.

Treatment sequencing of metastatic colorectal cancer based on primary tumor location

Colorectal cancer is a heterogeneous disease with various clinical, molecular, and embryological differences related to the origin of the tumor from the right or left colon. Recent studies have demonstrated that tumor sidedness has both a prognostic and predictive value in metastatic colorectal cancer . Patients whose primary tumor originates from the left side of the colon and whose tumor's genome encodes wild-type RAS and BRAF should be offered cetuximab or panitumumab in the first-line treatment of metastatic disease or in subsequent lines. For tumors originating from the right side of the colon, anti-angiogenic treatment, particularly bevacizumab, is an option for this poor prognostic group until better options become available. Specifically, an aggressive initial approach with FOLFOXIRI plus bevacizumab is a treatment option in right-sided tumors under investigation. This report reviews the available data for the treatment of metastatic colorectal cancer according to the location of the primary tumor and proposes the optimal treatment sequencing strategy incorporating the site of origin of the tumor and molecular information into the decision-making process.

Systemic Chemotherapy is a Promising Treatment Option for Patients with Colonic Stents: A Review

Approximately 10% of patients with colorectal cancer (CRC) develop malignant large bowel obstruction (MLBO) at diagnosis. Furthermore, for 35% of patients with MLBO, curative primary tumor resection is unfeasible because of locally advanced disease and comorbidities. The practice of placing a self-expandable metallic stent (SEMS) has dramatically increased as an effective palliative treatment. Recent advances in systemic chemotherapy for metastatic CRC have significantly contributed to prolonging patients' prognosis and expanding the indications. However, the safety and efficacy of systemic chemotherapy in patients with SEMS have not been established. This review outlines the current status of this relatively new therapeutic strategy and future perspectives. Some reports on this topic have demonstrated that 1) systemic chemotherapy and the addition of molecular targeted agents contribute to prolonged survival in patients with SEMS; 2) delayed SEMS-related complications are a major concern, and this requires strict patient monitoring; however, primary tumor control by chemotherapy might result in decreased complications, especially regarding re-obstruction; and 3) using bevacizumab could be a risk factor for SEMS-related perforation, which may be lethal. Although this relatively new approach for unresectable stage IV obstructive CRC requires a well-planned clinical trial, this therapy could be promising for patients who are unideal candidates for emergency surgery and require immediate systemic chemotherapy.

Clinical impact of primary tumour location, early tumour shrinkage, and depth of response in the treatment of metastatic colorectal cancer with first-line chemotherapy plus cetuximab or bevacizumab

The primary tumour location is an important prognostic factor for previously untreated metastatic colorectal cancer (mCRC). However, the predictive efficacies of primary tumour location, early tumour shrinkage (ETS), and depth of response (DpR) on mCRC treatment has not been fully evaluated. This study aimed to investigate the predictive efficacies of these traits in mCRC patients treated with first-line 5-fluorouracil-based chemotherapy plus biologic agents, namely, cetuximab and bevacizumab. This was a retrospective analysis of the medical records of 110 patients with pathology-documented unresectable mCRC. Patients with left-sided mCRC receiving any first-line regimen showed better overall survival (OS) than those with right-sided mCRC [33.3 vs 16.3 months; hazard ratio (HR) 0.44; 95% confidence interval (CI) 0.27–0.74; p < 0.001]. In patients with left-sided tumours, treatment with chemotherapy plus cetuximab yielded longer OS than chemotherapy plus bevacizumab (50.6 vs 27.8 months, HR 0.55; 95% CI 0.32–0.97; p = 0.0378). mCRC patients with ETS and high DpR showed better OS than those lacking ETS and with low DpR (33.5 vs 19.6 months, HR 0.50, 95% CI 0.32–0.79, p = 0.023 and 38.3 vs 19.0 months, HR 0.43, 95% CI 0.28–0.68, p < 0.001, respectively). Moreover, ETS and/or high DpR achieved in patients with right-sided mCRC receiving chemotherapy plus cetuximab were associated with significantly better OS than in those lacking ETS and with low DpR (34.3 vs 10.4 months, HR 0.19, 95% CI 0.04–0.94, p = 0.025 and 34.3 vs 10.4 months, HR 0.19, 95% CI 0.04–0.94, p = 0.0257, respectively). Taken together, our study demonstrates that primary tumour location is not only a well-known prognostic factor but also a relevant predictive factor in patients with mCRC receiving chemotherapy plus cetuximab. Additionally, both ETS and DpR could predict treatment outcomes and also potentially guide cetuximab treatment even in right-sided mCRCs.

Simulating Progression-Free and Overall Survival for First-Line Doublet Chemotherapy With or Without Bevacizumab in Metastatic Colorectal Cancer Patients Based on Real-World Registry Data

BACKGROUND

Simulation models utilizing real-world data have potential to optimize treatment sequencing strategies for specific patient subpopulations, including when conducting clinical trials is not feasible. We aimed to develop a simulation model to estimate progression-free survival (PFS) and overall survival for first-line doublet chemotherapy with or without bevacizumab for specific subgroups of metastatic colorectal cancer (mCRC) patients based on registry data.

METHODS

Data from 867 patients were used to develop two survival models and one logistic regression model that populated a discrete event simulation (DES). Discrimination and calibration were used for internal validation of these models separately and predicted and observed medians and Kaplan-Meier plots were compared for the integrated DES. Bootstrapping was performed to correct for optimism in the internal validation and to generate correlated sets of model parameters for use in a probabilistic analysis to reflect parameter uncertainty.

RESULTS

The survival models showed good calibration based on the regression slopes and modified Hosmer-Lemeshow statistics at 1 and 2 years, but not for short-term predictions at 0.5 years. Modified C-statistics indicated acceptable discrimination. The simulation estimated that median first-line PFS (95% confidence interval) of 219 (25%) patients could be improved from 175 days (156-199) to 269 days (246-294) if treatment would be targeted based on the highest expected PFS.

CONCLUSIONS

Extensive internal validation showed that DES accurately estimated the outcomes of treatment combination strategies for specific subpopulations, with outcomes suggesting treatment could be optimized. Although results based on real-world data are informative, they cannot replace randomized trials.

Primary Tumor Location and Outcomes After Cytoreductive Surgery and Intraperitoneal Chemotherapy for Peritoneal Metastases of Colorectal Origin

BACKGROUND

The aim of this study is to evaluate outcomes in patients with peritoneal metastasis of colorectal cancer (pmCRC) who underwent cytoreductive surgery and intraperitoneal chemotherapy (CRS/IPC) in relation to the location of the primary tumor. Regional therapy, including cytoreductive surgery and intraperitoneal chemotherapy, has been associated with improved survival in patients with pmCRC. Location of the primary tumor has been shown to be prognostic in patients with metastasis.

PATIENTS AND METHODS

A retrospective review was performed for all patients who underwent complete cytoreduction and intraperitoneal chemotherapy from 2010 to 2017, examining patient and tumor characteristics, overall and recurrence-free survival, recurrence patterns, and tumor mutational profiles.

RESULTS

Ninety-three patients were included in the study: 49 (53%) with a right-sided and 44 (47%) with a left-sided primary tumor. Patients with a right-sided tumor had significantly shorter recurrence-free survival (median, 6.3 months; 95% CI, 4.7-8.1 months vs 12.3 months; 95% CI, 3.6-21.7 months; P = 0.02) and overall survival (median, 36.6 months; 95% CI, 26.4-46.9 months vs 83.3 months; 95% CI 44.2-122.4 months; P = 0.03). BRAF and KRAS mutations were more frequent in right-sided tumors, and APC and TP53 mutations were more frequent in left-sided tumors, which were more chromosomally instable. BRAF mutations were associated with early recurrence.

CONCLUSIONS

Tumor sidedness is a predictor of oncological outcomes after CRS/IPC. Tumor sidedness and molecular characteristics should be considered when counseling patients regarding expected outcomes and when selecting or stratifying pmCRC patients for clinical trials of regional therapy.

A Qualitative Transcriptional Signature for Predicting Prognosis and Response to Bevacizumab in Metastatic Colorectal Cancer

Bevacizumab is the molecular-targeted agent used for the antiangiogenic therapy of metastatic colorectal cancer. But some patients are resistant to bevacizumab, it needs an effective biomarker to predict the prognosis and responses of metastatic colorectal cancer (mCRC) to bevacizumab therapy. In this work, we developed a qualitative transcriptional signature to individually predict the response of bevacizumab in patients with mCRC. First, using mCRC samples treated with bevacizumab, we detected differentially expressed genes between response and nonresponse groups. Then, the gene pairs, consisting of at least one differentially expressed gene, with stable relative expression orderings in the response samples but reversal stable relative expression orderings in the nonresponse samples were identified, denoted as pairs-bevacizumab. Similarly, we screened the gene pairs significantly associated with primary tumor locations, donated as pairs-LR. Among the overlapped gene pairs between the pairs-bevacizumab and pairs-LR, we adopted a feature selection process to extract gene pairs that reached the highest F-score for predicting bevacizumab response status in mCRC as the final gene pair signature (GPS), denoted as 64-GPS. In two independent datasets, the predicted response group showed significantly better overall survival than the nonresponse group (P = 6.00e-4 in GSE72970; P = 0.04 in TCGA). Genomic analyses showed that the predicted response group was characterized by frequent copy number alternations, whereas the nonresponse group was characterized by hypermutation. In conclusion, 64-GPS was an objective and robust predictive signature for patients with mCRC treated with bevacizumab, which could effectively assist in the decision of clinical therapy.

Incidence and prognosis of pulmonary metastasis in colorectal cancer: a population-based study

PURPOSE

It is unclear how primary tumor location affects the pulmonary metastasis in colorectal cancer patients with different primary tumor locations. We aim to explore the relationship between primary tumor location and the incidence and prognosis of colorectal cancer patients with pulmonary metastasis at diagnosis.

METHODS

From Surveillance, Epidemiology, and End Results (SEER) database, 9920 out of 192,969 CRC patients were identified with pulmonary metastasis at diagnosis between 2010 and 2015. Patients were classified into three subsets according to primary tumor location. The incidence of pulmonary metastasis and median survival were calculated. Multivariable logistic and Cox regression were performed to identify the risk factors of pulmonary metastasis and prognosis.

RESULTS

The incidence of pulmonary metastasis was 5.14% in the entire colorectal cancer cohort and 25.66% in metastatic colorectal cancer patients. The median survival of those patients was 10 months. Rectal cancer patients exhibited the highest incidence of pulmonary metastasis, while they had the longest median survival (15 months). The right-sided colon cancer patients had the lowest incidence of pulmonary metastasis, but the shortest median survival (8 months). 61 to 80 years old, over 80, black, two or three extrapulmonary metastatic sites and CEA-positive had a negative influence both on the incidence and prognosis.

CONCLUSIONS

The importance of primary tumor location in affecting the incidence of pulmonary metastasis and prognosis of colorectal cancer patients was highlighted in this study. Primary tumor location should be considered in clinical interference and personalized treatment for colorectal cancer patients with pulmonary metastasis.

Prognostic Heterogeneity of MRE11 Based on the Location of Primary Colorectal Cancer Is Caused by Activation of Different Immune Signals

Background: MRE11 plays an important role in DNA damage response for the maintenance of genome stability, and is becoming a prognostic marker for cancers, including colorectal cancer (CRC). However, the correlations of MRE11 to prognosis and tumor-infiltrating inflammatory cells (TIICs) in different locations of CRC remains unclear.

Methods: Among Swedish and TCGA-COREAD patients, we investigated the association of MRE11 expression, tumor-infiltrating inflammatory cells (TIICs) and microsatellite status with survival in right-sided colon cancer (RSCC) and left-sided colon and rectal cancer (LSCRC). The signaling of MRE11-related was further analyzed using weighted gene co-expression network analysis and ClueGO.

Results: High MRE11 expression alone or combination of high MRE11 expression with high TIICs was related to favorable prognosis in LSCRC. Moreover, high MRE11 expression was associated with favorable prognosis in LSCRC with microsatellite stability. The relationships above were adjusted for tumor stage, differentiation, and/or TIICs. However, no such evidence was observed in RSCC. Several signaling pathways involving MRE11 were found to be associated with cell cycle and DNA repair in RSCC and LSCRC, whereas, the activation of the immune response and necrotic cell death were specifically correlated with LSCRC.

Conclusions: High MRE11 expression is an independent prognostic marker in LSCRC and enhanced prognostic potency of combining high MRE11 with high TIICs in LSCRC, mainly due to differential immune signaling activated by MRE11 in RSCC and LSCRC, respectively.

Association of Primary Tumor Site With Mortality in Patients Receiving Bevacizumab and Cetuximab for Metastatic Colorectal Cancer

Importance

Biologic therapy (BT) (eg, bevacizumab or cetuximab) is increasingly used to treat metastatic colorectal cancer (mCRC). Recent investigations have suggested that right- or left-sided primary tumor origin affects survival and response to BT.

Objective

To evaluate the association of tumor origin with mortality in a diverse population-based data set of patients receiving systemic chemotherapy (SC) and bevacizumab or cetuximab for mCRC.

Design, Setting, and Participants

This population-based nonconcurrent cohort study of statewide California Cancer Registry data included all patients aged 40 to 85 years diagnosed with mCRC and treated with SC only or SC plus bevacizumab or cetuximab from January 1, 2004, through December 31, 2014. Patients were stratified by tumor origin in the left vs right sides.

Interventions

Treatment with SC or SC plus bevacizumab or cetuximab.

Main Outcomes and Measures

Mortality hazards by tumor origin (right vs left sides) were assessed for patients receiving SC alone or SC plus bevacizumab or cetuximab. Subgroup analysis for patients with wild-type KRAS tumors was also performed.

Results

A total of 11 905 patients with mCRC (6713 men [56.4%] and 5192 women [43.6%]; mean [SD] age, 60.0 [10.9] years) were eligible for the study. Among these, 4632 patients received SC and BT. Compared with SC alone, SC plus bevacizumab reduced mortality among patients with right- and left-sided mCRC, whereas SC plus cetuximab reduced mortality only among patients with left-sided tumors and was associated with significantly higher mortality for right-sided tumors (hazard ratio [HR], 1.31; 95% CI, 1.14-1.51; P < .001). Among patients treated with SC plus BT, right-sided tumor origin was associated with higher mortality among patients receiving bevacizumab (HR, 1.31; 95% CI, 1.25-1.36; P < .001) and cetuximab (HR, 1.88; 95% CI, 1.68-2.12; P < .001) BT, compared with left-sided tumor origin. In patients with wild-type KRAS tumors (n = 668), cetuximab was associated with reduced mortality among only patients with left-sided mCRC compared with bevacizumab (HR, 0.75; 95% CI, 0.63-0.90; P = .002), whereas patients with right-sided mCRC had more than double the mortality compared with those with left-sided mCRC (HR, 2.44; 95% CI, 1.83-3.25, P < .001).

Conclusions and Relevance

Primary tumor site is associated with response to BT in mCRC. Right-sided primary tumor location is associated with higher mortality regardless of BT type. In patients with wild-type KRAS tumors, treatment with cetuximab benefited only those with left-sided mCRC and was associated with significantly poorer survival among those with right-sided mCRC. Our results underscore the importance of stratification by tumor site for current treatment guidelines and future clinical trials.

Does Primary Tumor Side Matter in Patients with Metastatic Colon Cancer Treated with Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy?

BACKGROUND

Primary tumor location has been shown to be prognostic of overall survival (OS) in patients with both locally advanced and metastatic colorectal cancer. The impact of sidedness on prognosis has not been evaluated in the setting of peritoneal-only metastases treated with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC).

METHODS

A retrospective review of prospectively maintained databases of patients with peritoneal surface malignancy undergoing CRS/HIPEC from three high-volume centers was performed.

RESULTS

A total of 115 patients with metastatic colon cancer to the peritoneum who underwent CRS/HIPEC with mitomycin C were identified. Fifty-one patients (45%) had left-sided primary tumors, and 64 (55%) had right-sided primary tumors. Patients with right-sided tumors were more likely to be older (median age 56 vs. 49 years, p = 0.007) and to have signet ring cell histology (17% vs. 4%, p = 0.026). Patients with right-sided tumors had median disease-free survival (DFS) and OS of 14 months (95% confidence interval [CI] 10.5-17.5) and 36 months (95% CI 27.4-44.6), respectively, versus 16 months (95% CI 11.0-21.0) and 69 months (95% CI 24.3-113.7) for those patients with left-sided tumors. On multivariate analysis, primary tumor side was an independent predictor of both DFS and OS.

CONCLUSIONS

In this study, there was a dramatic, clinically significant difference in OS between patients with right- and left-sided tumors, and primary tumor side was an independent predictor of DFS and OS. Primary tumor side should be considered in patient selection for CRS with or without HIPEC.

Right versus left sided metastatic colorectal cancer: Teasing out clinicopathologic drivers of disparity in survival

BACKGROUND

Metastatic colorectal cancer (mCRC) patients with a right-sided primary (RC) have an inferior survival to mCRC arising from a left-sided primary (LC). Previous analyses have suggested multiple factors contribute.

METHODS

The Treatment of Recurrent and Advanced Colorectal Cancer (TRACC) Registry prospectively captured data on consecutive mCRC patients. RC were defined as tumors proximal to the splenic flexure; LC were those at and distal to the splenic flexure and included rectal cancers. Patient, tumor, treatment, and survival data were analyzed stratified by side.

RESULTS

Of 2306 patients enrolled from July 2009-March 2018, 747 (32%) had an RC. Patients with RC were older, more likely to be female and have a Charlson score ≥3. RC were more frequently BRAF mutated, deficient in mismatch repair, associated with peritoneal metastases, and less likely to receive chemotherapy. Progression-free survival on first-line systemic therapy was inferior for RC patients (8.1 vs. 10.8 months, hazard ratio [HR] for progression in RC 1.38, P < 0.001). Median overall survival for all RC patients was inferior (19.6 vs. 27.5 months, HR for death in RC 1.44, P < 0.001), and inferior within the treated (21 vs. 29.5 months, HR 1.52, P < 0.001) and untreated subgroups (5.9 vs. 10.3 months, HR 1.38, P = 0.009). Primary side remained a significant factor for overall survival in multivariate analysis.

CONCLUSION

Our data from a real-world population confirms the poorer prognosis associated with RC. Primary tumor location remains significantly associated with overall survival even when adjusting for multiple factors, indicating the existence of further side-based differences that are as yet undefined.

Right or Left Primary Site of Colorectal Cancer: Outcomes From the Molecular Analysis of the AGITG MAX Trial

BACKGROUND

For metastatic colorectal cancer, previous reports have described differences in biology and outcome, including response to biologic agents, based on whether the primary tumor is right- or left-sided. We explored the molecular markers from the AGITG MAX trial.

PATIENTS AND METHODS

The AGITG MAX trial was a randomized study comparing capecitabine versus capecitabine + bevacizumab versus capecitabine + bevacizumab + mitomycin C as first-line therapy in advanced colorectal cancer. Patients were classified as having right-sided (caecum to transverse colon) or left-sided (descending colon to rectum) disease according to anatomic location. Baseline characteristics and previously described molecular profiles were compared by side of primary tumor. Survival outcomes were analyzed by the Kaplan-Meier approach and proportional hazards regression modeling.

RESULTS

Among the 471 patients, the location of primary tumor was known in 440 patients (93%). Molecular profile was known in 298 patients (63%). Twenty-eight percent had right-sided primary tumors. Major differences between right and left are as follows: female 49% versus 33% (P < .01), BRAF mutant 16% versus 3.5% (P ≤ .001), and phosphatase and tensin homolog (PTEN) loss 27.6% versus 53% (P = .01). There were no differences in RAS mutation, PIK3CA mutation, or high versus low expression of assessed angiogenic markers. Right-sided primary lesion predicted a poor outcome for median overall survival: right-sided disease 13.2 months versus left-sided disease 20 months (P = .001; hazard ratio [HR] = 0.67; 95% confidence interval [CI], 0.53-0.85), but not for progression-free survival (HR 0.96; 95% CI, 0.78-1.20). The relative treatment effect did not differ significantly according to location of primary tumor: right primary tumor HR (bevacizumab containing arm vs. capecitabine monotherapy arm) was 0.82 (95% CI, 0.54-1.22), and left primary HR (bevacizumab containing arm vs. capecitabine monotherapy arm) was 0.51 (95% CI, 0.4-0.63) (interaction P = .10).

CONCLUSION

There are more negative prognostic factors in patients with right-sided primary tumors, in particular high BRAF mutations, and these patients have inferior overall survival compared to those with a left-sided primary tumor. There was no suggestion that side of primary site had any impact on bevacizumab effect on progression-free survival.

Biomarker analysis beyond angiogenesis: RAS/RAF mutation status, tumour sidedness, and second-line ramucirumab efficacy in patients with metastatic colorectal carcinoma from RAISE-a global phase III study

Background

: Second-line treatment with ramucirumab+FOLFIRI improved overall survival (OS) versus placebo+FOLFIRI for patients with metastatic colorectal carcinoma (CRC) [hazard ratio (HR)=0.84, 95% CI 0.73-0.98, P = 0.022]. Post hoc analyses of RAISE patient data examined the association of RAS/RAF mutation status and the anatomical location of the primary CRC tumour (left versus right) with efficacy parameters.

Patients and methods

Patient tumour tissue was classified as BRAF mutant, KRAS/NRAS (RAS) mutant, or RAS/BRAF wild-type. Left-CRC was defined as the splenic flexure, descending and sigmoid colon, and rectum; right-CRC included transverse, ascending colon, and cecum.

Results

RAS/RAF mutation status was available for 85% of patients (912/1072) and primary tumour location was known for 94.4% of patients (1012/1072). A favourable and comparable ramucirumab treatment effect was observed for patients with RAS mutations (OS HR = 0.86, 95% CI 0.71-1.04) and patients with RAS/BRAF wild-type tumours (OS HR = 0.86, 95% CI 0.64-1.14). Among the 41 patients with BRAF-mutated tumours, the ramucirumab benefit was more notable (OS HR = 0.54, 95% CI 0.25-1.13), although, as with the other genetic sub-group analyses, differences were not statistically significant. Progression-free survival (PFS) data followed the same trend. Treatment-by-mutation status interaction tests (OS P = 0.523, PFS P = 0.655) indicated that the ramucirumab benefit was not statistically different among the mutation sub-groups, although the small sample size of the BRAF group limited the analysis. Addition of ramucirumab to FOLFIRI improved left-CRC median OS by 2.5 month over placebo (HR = 0.81, 95% CI 0.68-0.97); median OS for ramucirumab-treated patients with right-CRC was 1.1 month over placebo (HR = 0.97, 95% CI 0.75-1.26). The treatment-by-sub-group interaction was not statistically significant for tumour sidedness (P = 0.276).

Conclusions

In the RAISE study, the addition of ramucirumab to FOLFIRI improved patient outcomes, regardless of RAS/RAF mutation status, and tumour sidedness. Ramucirumab treatment provided a numerically substantial benefit in BRAF-mutated tumours, although the P-values were not statistically significant.

ClinicalTrials.gov number

NCT01183780.

Prognostic Value of the Tumor Size in Resectable Colorectal Cancer with Different Primary Locations: A Retrospective Study with the Propensity Score Matching

Objective: To investigate the prognostic value of the tumor size in colorectal cancer (CRC) patients with different primary tumor locations. Patients and methods: We retrospectively recruited 3971 stage I-III CRC patients with curative resection. The propensity score matching technique was conducted to reduce the selection bias, producing a propensity score matched cohort of 1347 pairs of patients based on the tumor size (≤4 cm and >4 cm groups). Kaplan-Meier survival analyses and univariate and multivariate analyses were used to compare the overall survival (OS), cancer-specific survival (CSS) and disease-free survival (DFS) between the two groups. Subgroup analyses which were stratified by primary tumor locations and several other baseline variables were also performed for conformation. Results: In the propensity score matched cohort, the Kaplan-Meier survival curves revealed that patients with a tumor size less than 4 cm had similar OS, CSS and DFS, compared to patients with a tumor size greater than 4 cm. While in multivariate analyses, the smaller tumor size was an independent risk factor for CSS (HR, 1.275; 95% CI, 1.006-1.616; P=0.045). Subgroup analyses based on primary tumor locations further suggested that the smaller tumor size was significantly associated with worse OS (HR, 2.455; 95% CI, 1.297-4.649; P=0.006) and CSS (HR, 2.493; 95% CI, 1.202-5.174; P=0.014) in patients with right-side colon cancers (RCC). Conclusions: Our propensity matching score study indicated that the smaller tumor size was an independent risk factor for CSS in patients with stage I-III CRC, and for OS and CSS in patients with RCC.

Impact of primary tumour location on efficacy of bevacizumab plus chemotherapy in metastatic colorectal cancer

Background

Two first-line (1L) bevacizumab trials showed the prognostic value of primary tumour location in metastatic colorectal cancer (mCRC). In this retrospective subgroup analysis, further analysis of the predictive effect of bevacizumab is presented.

Methods

Patients with sidedness information from two randomised phase III studies of bevacizumab + chemotherapy (CT) vs CT as 1L mCRC treatment were analysed retrospectively.

Results

Sidedness was determined in 1590 (27% right and 73% left) of 2214 patients. Progression-free survival was improved with bevacizumab + CT vs CT in right-sided (HR = 0.75; 95% CI 0.61, 0.93; p = 0.008) and left-sided (HR = 0.76; 95% CI 0.67, 0.86; p < 0.001) mCRC (pooled analysis). Similarly, overall survival was numerically improved with bevacizumab + CT vs CT in right-sided mCRC (HR = 0.82; 95% CI 0.65, 1.03; p = 0.085), and significantly improved in left-sided mCRC (HR = 0.85; 95% CI 0.74, 0.98; p = 0.028).

Conclusions

This analysis indicates that the effect of bevacizumab is independent of tumour location in mCRC.

Real-world use of bevacizumab in metastatic colorectal, metastatic breast, advanced ovarian and cervical cancer: a systematic literature review

AIM

This review aims to assist physicians and payers in assessing the efficacy and safety of bevacizumab in real-world clinical practice by identifying evidence on the comparative effectiveness and safety of bevacizumab in its most frequent indications. Materials & methods: In a systematic review of the published literature, electronic databases (Embase^®, MEDLINE^® and the Cochrane Library) were searched in May 2016 and updated in January 2017; 20 scientific congresses were searched in 2014-2017.

RESULTS

Of 61 included publications, 49, eight, four and 0 concerned metastatic colorectal cancer, metastatic breast cancer, advanced ovarian cancer and cervical cancer, respectively. Fifteen publications (metastatic colorectal cancer) reported on factors predictive of response to therapy.

CONCLUSION

Effectiveness findings from real-world studies broadly supported results from registration studies.

Proximal shift of colorectal cancer with increasing age in different ethnicities

Background

Studies have indicated a variation in colon cancer pathology with increased age. More findings have also suggested differences in genetics, biology, and demography in terms of ethnicity. Large-scale studies closely examining tumor location shift with aging and ethnicity are scarce.

Objective

We compared the tumor location shift with aging and the difference in survival based on tumor location by age group among the African-American, White, and Asian/Pacific Islander patients with colorectal cancer.

Materials and methods

We collected 270,390 cases from the Surveillance, Epidemiology, and End Results database between 2004 and 2014. Ethnicity distribution between younger (age <70 years) and older (age ≥70 years) patients was analyzed using univariate and multivariate logistic regression. The Kaplan–Meier method was used to compare the tumor location survival difference in the African-American, White, and Asian/Pacific Islander patients.

Results

Larger tumors, female sex, M0, advanced N stage, no treatment, moderate to poor differentiation, total number of lymph nodes evaluated >12, and right-sided colon cancer were more common in patients aged ≥70 years. More adverse prognosis was found in younger patients compared to older patients. Tumor location frequency differed based on age; the most pronounced differences were found in White patients. The right-sided colon cancer survival inferiority was present only in White patients.

Conclusion

Our findings support the premise of etiological and carcinogenic differences based on tumor location and between younger and older patients.

Risk Factors and Adequate Management for Complications of Bevacizumab Treatment Requiring Surgical Intervention in Patients With Metastatic Colorectal Cancer

BACKGROUND

Bevacizumab (BV) has been approved for treating colorectal cancer since 2004. Although BV use may lead to adverse effects, few studies have reported incidences requiring surgical intervention. We aimed to identify the risk factors and adequate interventions for complications requiring surgical intervention after BV treatment.

PATIENTS AND METHODS

We retrospectively reviewed the records of patients with metastatic colorectal cancer treated with BV in our institute from January 2009 to December 2016. The baseline patient characteristics were used to evaluate the potential risk factors for complications requiring surgery.

RESULTS

Of the 1008 patients recruited for this study, 60 (5.9%) experienced complications necessitating surgery after BV therapy. Gastrointestinal perforation was the most frequently observed complication, occurring in 36 patients (3.5%), and diverting colostomy was the most commonly performed intervention (22 patients, 36.6%). Multivariate analysis helped identify poor differentiation, signet ring cell carcinoma, stent insertion status, rectal location of the primary tumor, and intact primary tumor status as the risk factors. Survival time remained unchanged regardless of a complication that required surgery.

CONCLUSION

Careful monitoring during BV treatment for metastatic colorectal cancer is essential for patients who have a predisposition to complications that may require surgery. After detection, adequate and timely surgical management is imperative for ensuring patient survival.

Primary Tumor Location in Colorectal Cancer: Comparison of Right- and Left-Sided Colorectal Cancer Characteristics for the Interventional Radiologist

One area which has emerged as an important factor for predicting molecular profile and treatment outcomes in metastatic colorectal cancer (mCRC) is primary tumor location. The importance of molecular characteristics of colorectal cancer has been firmly established in terms of prognosis and treatment algorithms for many years. Recent studies have also suggested that molecular profiles are important in locoregional therapies as well, with some data suggesting changes in treatment algorithms based on tumor location. Therefore, it is important for interventional radiologists to understand the basic molecular characteristics and development pathways of mCRC. Here, these disease characteristics are reviewed and the differences in left- versus right-sided primary tumor location are explored.

Stage-based Variation in the Effect of Primary Tumor Side on All Stages of Colorectal Cancer Recurrence and Survival

BACKGROUND

Multiple studies have defined the prognostic and potential predictive significance of the primary tumor side in metastatic colorectal cancer (CRC). However, the currently available data for early-stage disease are limited and inconsistent.

MATERIALS AND METHODS

We explored the clinicopathologic, treatment, and outcome data from a multisite Australian CRC registry from 2003 to 2016. Tumors at and distal to the splenic flexure were considered a left primary (LP).

RESULTS

For the 6547 patients identified, the median age at diagnosis was 69 years, 55% were men, and most (63%) had a LP. Comparing the outcomes for right primary (RP) versus LP, time-to-recurrence was similar for stage I and III disease, but longer for those with a stage II RP (hazard ratio [HR], 0.68; 95% confidence interval [CI], 0.52-0.90; P < .01). Adjuvant chemotherapy provided a consistent benefit in stage III disease, regardless of the tumor side. Overall survival (OS) was similar for those with stage I and II disease between LP and RP patients; however, those with stage III RP disease had poorer OS (HR, 1.30; 95% CI, 1.04-1.62; P < .05) and cancer-specific survival (HR, 1.55; 95% CI, 1.19-2.03; P < .01). Patients with stage IV RP, whether de novo metastatic (HR, 1.15; 95% CI, 0.95-1.39) or relapsed post-early-stage disease (HR, 1.35; 95% CI, 1.11-1.65; P < .01), had poorer OS.

CONCLUSION

In early-stage CRC, the association of tumor side and effect on the time-to-recurrence and OS varies by stage. In stage III patients with an RP, poorer OS and cancer-specific survival outcomes are, in part, driven by inferior survival after recurrence, and tumor side did not influence adjuvant chemotherapy benefit.

Prognostic and predictive value of primary tumour side in patients with RAS wild-type metastatic colorectal cancer treated with chemotherapy and EGFR directed antibodies in six randomized trials

Background

There is increasing evidence that metastatic colorectal cancer (mCRC) is a genetically heterogeneous disease and that tumours arising from different sides of the colon (left versus right) have different clinical outcomes. Furthermore, previous analyses comparing the activity of different classes of targeted agents in patients with KRAS wild-type (wt) or RAS wt mCRC suggest that primary tumour location (side), might be both prognostic and predictive for clinical outcome.

Methods

This retrospective analysis investigated the prognostic and predictive influence of the localization of the primary tumour in patients with unresectable RAS wt mCRC included in six randomized trials (CRYSTAL, FIRE-3, CALGB 80405, PRIME, PEAK and 20050181), comparing chemotherapy plus EGFR antibody therapy (experimental arm) with chemotherapy or chemotherapy and bevacizumab (control arms). Hazard ratios (HRs) and 95% confidence intervals (CIs) for overall survival (OS) and progression-free survival (PFS) for patients with left-sided versus right-sided tumours, and odds ratios (ORs) for objective response rate (ORR) were estimated by pooling individual study HRs/ORs. The predictive value was evaluated by pooling study interaction between treatment effect and tumour side.

Results

Primary tumour location and RAS mutation status were available for 2159 of the 5760 patients (37.5%) randomized across the 6 trials, 515 right-sided and 1644 left-sided. A significantly worse prognosis was observed for patients with right-sided tumours compared with those with left-sided tumours in both the pooled control and experimental arms for OS [HRs = 2.03 (95% CI: 1.69-2.42) and 1.38 (1.17-1.63), respectively], PFS [HRs = 1.59 (1.34-1.88) and 1.25 (1.06-1.47)], and ORR [ORs = 0.38 (0.28-0.50) and 0.56 (0.43-0.73)]. In terms of a predictive effect, a significant benefit for chemotherapy plus EGFR antibody therapy was observed in patients with left-sided tumours [HRs = 0.75 (0.67-0.84) and 0.78 (0.70-0.87) for OS and PFS, respectively] compared with no significant benefit for those with right-sided tumours [HRs = 1.12 (0.87-1.45) and 1.12 (0.87-1.44) for OS and PFS, respectively; P value for interaction <0.001 and 0.002, respectively]. For ORR, there was a trend (P value for interaction = 0.07) towards a greater benefit for chemotherapy plus EGFR antibody therapy in the patients with left-sided tumours [OR = 2.12 (1.77-2.55)] compared with those with right-sided tumours [OR = 1.47 (0.94-2.29)]. Exclusion of the unique phase II trial or the unique second-line trial had no impact on the results. The predictive effect on PFS may depend of the type of EGFR antibody therapy and on the presence or absence of bevacizumab in the control arm.

Conclusion

This pooled analysis showed a worse prognosis for OS, PFS and ORR for patients with right-sided tumours compared with those with left-sided tumours in patients with RAS wt mCRC and a predictive effect of tumour side, with a greater effect of chemotherapy plus EGFR antibody therapy compared with chemotherapy or chemotherapy and bevacizumab, the effect being greatest in patients with left-sided tumours. These predictive results should be interpreted with caution due to the retrospective nature of the analysis, which was carried out on subpopulations of patients included in these trials, and because none of these studies contemplated a full treatment sequence strategy.

Differences between carcinoma of the cecum and ascending colon: Evidence based on clinical and embryological data

Developing rapidly from the cecal diverticulum in a 5-week-old embryo, the cecum, which is developed from the caudal limb of the midgut loop, is different from the ascending colon. The aim of this study was to analyze the different clinicopathological and biological characteristics of patients with carcinoma of the cecum and ascending colon. We accessed data for 59,035 patients with adenocarcinomas of the cecum and ascending colon from the Surveillance, Epidemiology and End Results database to explore the potential associations between the clinicopathological characteristics and overall survival. Furthermore, we analyzed the differences in gene expression between the two segments in the Gene Expression Omnibus database. The results were validated in The Cancer Genome Atlas database, as well as with another independent dataset from the First Affiliated Hospital of Xi'an Jiaotong University. The results of this study revealed the potential prognostic differences between adenocarcinoma of the cecum and ascending colon, which may be caused by the differential expression levels of the SLCO1B3 gene. When including the expression levels of SLCO1B3 in intraoperatively examined lymph nodes, 8 factors were found able to predict the prognosis of patients with carcinomas of the cecum and ascending colon. As regards the surgical therapeutic strategies, the resection of >15 local lymph nodes is appropriate for improving the prognosis of patients.

Tumor location impact in stage II and III colon cancer: epidemiological and outcome evaluation

Background

We aimed to describe clinico-pathological characteristics and differences between right-sided (RCC) and left-sided colon cancer (LCC) in Tunisian population. We also analyzed outcome to determine whether location is of prognostic significance.

Methods

Clinico-pathological characteristics and Kaplan Meier survival were compared between two groups of LCC [150] and RCC [53] patients with stage II and III adenocarcinoma treated with curative intent between 2003-2014.

Results

RCC patients were significantly more likely to be female, (56.6% vs. 39.3%, P=0.029) and to have undifferentiated tumor (87.1% vs. 8.4%, P=0.014), then LCC. After a median follow up of 49 months, 5-year overall survival (OS) was significantly worse in RCC vs. LCC [42% vs. 78%; hazard ratio (HR) =2.07; 95% CI: 1.05-4.09; P=0.03], no difference in relapse free survival (RFS) was observed. Median time to relapse was significantly shorter in RCC (15 months) vs. LCC (24 months), P=0.005. Tumor location significantly impacted survival in stage III, 5-year OS was 45% in RCC, and 63% in LCC, (HR =2.28; 95% CI: 1.01-5.24; P=0.04), there was no impact of tumor location in stage II, (HR =1.94; 95% CI: 0.54-6.93; P=0.29).

Conclusions

Prognostic impact of tumor location should be considered as a stratification factor in the future clinical trials.

Polo-like kinase 2 promotes chemoresistance and predicts limited survival benefit from adjuvant chemotherapy in colorectal cancer

Colorectal cancer (CRC) is one of the most common malignances worldwide. Chemoresistance remains a major issue in the field of CRC treatment. The present study aimed to investigate the potential role of polo-like kinase 2 (Plk2) in chemoresistance in CRC. The associations between Plk2 and clinicopathological factors, as well as chemotherapeutic benefit were analyzed with a publicly available CRC dataset. The correlation between Plk2 expression and chemosensitivity was further confirmed in CRC cells. Moreover, knockdown and exogenous overexpression experiments of Plk2 were carried out to uncover the potential role of Plk2 in regulating the chemoresistance of CRC cells. We found that the expression of Plk2 was significantly associated with proximally located tumors. In addition, it was found that high expression ofPlk2 was associated with deficient mismatch repair status, B-raf serine/threonine kinase proto-oncogeneand Kirsten rat sarcoma viral oncogene homolog mutations. By contrast, tumor protein 53 mutation was correlated with a low expression level of Plk2. A higher expression level of Plk2 significantly predicted a poorer outcome in patients with CRC. However, the prognostic significance was only observed in patients who received adjuvant chemotherapy. In CRC cells, higher levels of Plk2 were associated with increased resistance to chemotherapeutic agents. Knocking down the expression of Plk2 resulted in elevated cellular apoptosis induced by oxaliplatin. By contrast, exogenous overexpression of Plk2 exerted an anti-apoptotic effect and enhanced the resistance of CRC cells to chemotherapeutic agents. In conclusion, a high expression of Plk2 was associated with chemoresistant traits of CRC through inhibiting apoptosis. These results suggested that Plk2 may serve as a predictive marker for chemoresistance and a novel target in CRC treatment.

Clinical baseline and prognostic difference of platelet lymphocyte ratio (PLR) in right-sided and let-sided colon cancers

Background

Right-sided colon cancer (RCC) and left-sided colon cancer (LCC) differ with respect to their biology and genomic patterns, but inflammatory index variation did not fully investigate. This study aimed to examine the difference of inflammatory indexes and its value between RCC and LCC.

Methods

The differences of common clinicopathologic factors, inflammatory indexes including PLR (Platelet lymphocyte ratio) between LCC and RCC were analyzed in the training cohort with logistic regression model, subsequently, confirmed in validation cohort. Kaplan-Meier analysis was applied for the analysis of the survival difference distinguished by the PLR and the Nonparametric Test was adopted to demonstrate the difference of PLR variation with the standard TNM classification between RCC and LCC.

Results

A total of 1846 CRC patients entered the study, 744 (40.3%) patients were RCC, 1102 (59.7%) were LCC. The patients’ number in both cohorts was 923. It was found that LCC patients in the training cohort significantly to be with higher CEA, adenocarcinoma, early UICC/AJCC stage, p-MMR (mismatch-repair proficient), and lower PLR, and the later four features were confirm in validation cohort. Higher PLR, the unique inflammatory index, was significantly associated with poorer OS in LCC cohort (P = 0.002) and was elevated with the TNM stage in the LCC patients (P < 0.001), however, the two relationships did not sustain in RCC patients.

Conclusion

Expect the classical characteristics, PLR, an inexpensive and easily assessable inflammatory index was found first time to be significant differ between LCC and RCC. Further, elevated PLR associated with poor OS (overall survival) in the LCC and more common in advanced TNM stage.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3862-8) contains supplementary material, which is available to authorized users.

Combination of primary tumor location and mismatch repair status guides adjuvant chemotherapy in stage II colon cancer

Background

Current opinions on the benefits of adjuvant chemotherapy for stage II colon cancer are divided and reformative election of these patients is required. We examined whether the primary tumor location based on mismatch repair status and other risk factors could better inform the current guideline.

Materials and Methods

A total of 673 consecutive patients with stage II colon cancer were included in the analysis. Differences in the common clinicopathological factors between left-sided colon cancer and right-sided colon cancer were analyzed using Fisher's exact analysis. Kaplan-Meier analysis was used to distinguish the survival difference by primary tumor location and/or MMR status.

Results

RCC had a shorter overall survival (P = 0.001) and Disease-free survival (P = 0.050) than LCC but was associated with survival benefit from adjuvant chemotherapy (P = 0.001 and P = 0.011 for OS and DFS, respectively). Mismatch repair-proficient had a shorter OS (P = 0.036) and disease free survival (P = 0.034) than mismatch-repair deficient but chemotherapy improved the OS (P = 0.007). When the primary tumor location and MMR status were combined, the PMMR/RCC was the only subgroup that could benefit from adjuvant chemotherapy (P < 0.001 and P = 0.002 for OS and DFS, respectively). Other tumors such as DMMR/RCC, DMMR/LCC, and PMMR/LCC did not benefit.

Conclusions

The observed survival benefits in PMMR/RCC patients treated with adjuvant chemotherapy will allow better selection of patients for chemotherapy who are in stage II.

KRAS mutation and primary tumor location do not affect efficacy of bevacizumab-containing chemotherapy in stagae IV colorectal cancer patients

This study aims to investigate the efficacy of bevacizumab-combined chemotherapy (BCC) in Chinese stage IV colorectal cancer (CRC), and analyze the relationship between clinicopathological features with survival. Patients with stage IV CRC treated with BCC were analyzed retrospectively. 217 metastatic CRC (mCRC) patients were collected, out of which79 were right-sided CRCs and 138 were left-sided ones. Patients with Eastern Cooperative Oncology Group (ECOG) performance status ≤2, single agent chemotherapy, poor/mucous/signet ring cell component, second-and further-line of bevacizumab administration, multiple metastasis sites had comparatively worse survival. Among 141 patients with known KRAS status, 55 patients harbored KRAS mutation and 86 had wild type KRAS. The ORR and DCR were 41.9% and 78.9%, respectively, in patients with wild type KRAS, while ORR and DCR was 38.7% and 77.9%, respectively, in patients with KRAS mutation. The median PFS of patients with wild type and mutant KRAS were 8.38, and9.59 months, respectively; whereas the OS was 23.00 and 21.26 months, respectively for mCRC patients with wild-type and mutant KRAS. Cumulatively, our study indicated that BCC was effective and beneficial for Chinese stage IV CRC patients. KRAS mutation status and tumor location were not a prognostic factor for survival.

Understanding the role of primary tumour localisation in colorectal cancer treatment and outcomes

Metastatic colorectal carcinoma (mCRC) is a heterogeneous disease with differing outcomes and clinical responses and poor prognosis. CRCs can be characterised by their primary tumour location within the colon. The left-sided colon, derived from the hindgut, includes the distal third of the transverse colon, splenic flexure, descending colon, sigmoid colon and rectum. The right-sided colon, derived from the midgut, includes the proximal two-thirds of the transverse colon, ascending colon and caecum. Sometimes, the rectum is described separately, despite originating from the hindgut, and in many clinical series, the left-sided colon includes only tumours within and distal to the splenic flexure. Differences in the microbiome, clinical characteristics and chromosomal and molecular characteristics have been reported between the right and left side of the colon, regardless of how this is defined. There is now strong evidence from clinical studies in patients with mCRC for the prognostic effect of primary tumour location. The impact of primary colonic tumour location on response to treatment is now under investigation in a large number of clinical studies in patients with mCRC. In this review, we summarise the microbiome, clinical, chromosomal and molecular differences associated with the primary location of CRC. We present an overview of the proven prognostic impact of primary tumour location for patients with mCRC and discuss emerging data for the predictive impact of primary tumour location on clinical outcome.

What roles do colon stem cells and gap junctions play in the left and right location of origin of colorectal cancers?

This "Commentary" examines an important clinical observation that right-sided colorectal cancers appear less treatable than the left-sided cancers. The concepts of (a) the "initiation/promotion/progression" process, (b) the stem cell hypothesis, (c) the role gap junctional intercellular communication, (d) cancer cells lacking GJIC either because of the non-expression of connexin genes or of non-functional gap junction proteins, and (e) the role of the microbiome in promoting initiated colon stem cells to divide symmetrically or asymmetrically are examined to find an explanation. It has been speculated that "embryonic-like" lesions in the ascending colon are initiated stem cells, promoted via symmetrical cell division, while the polyp-type lesions in the descending colon are initiated stem cells stimulated to divide asymmetrically. To test this hypothesis, experiments could be designed to examine if right-sided lesions might express Oct4A and ABCG2 genes but not any connexin genes, whereas the left-sided lesions might express a connexin gene, but not Oct4A or the ABCG2 genes. Treatment of the right sided lesions might include transcriptional regulators, whereas the left-sided lesions would need to restore the posttranslational status of the connexin proteins.

Primary tumor site and anti-EGFR monoclonal antibody benefit in metastatic colorectal cancer: a meta-analysis

AIM

This meta-analysis aimed to document the impact of primary tumor site on anti-EGFR monoclonal antibody (mAb) benefit in metastatic colorectal cancer.

MATERIALS & METHODS

Tumors with metastatic left-sided colorectal cancer (LCC) were compared with tumors with metastatic right-sided colon cancer (RCC) with respect to anti-EGFR mAb objective response rate (ORR), overall survival (OS) and progression-free survival (PFS) benefit.

RESULTS

Comparing LCC with RCC, LCC was found to have significantly superior anti-EGFR mAb ORR (p < 0.00001), OS (p < 0.00001) and PFS (p < 0.00001) benefit. Additionally, anti-EGFR mAb therapy significantly improved both OS and PFS for LCC compared with no anti-EGFR mAb therapy, but not for RCC. The test of interaction was also apparent for OS (p = 0.0002) and PFS (p = 0.0002).

CONCLUSION

This meta-analysis demonstrated that LCC had markedly superior anti-EGFR mAb treatment benefit compared with RCC.

Characteristics of Differently Located Colorectal Cancers Support Proximal and Distal Classification: A Population-Based Study of 57,847 Patients

Background

It has been suggested that colorectal cancer be regarded as several subgroups defined according to tumor location rather than as a single entity. The current study aimed to identify the most useful method for grouping colorectal cancer by tumor location according to both baseline and survival characteristics.

Methods

Cases of pathologically confirmed colorectal adenocarcinoma diagnosed from 2000 to 2012 were identified from the Surveillance, Epidemiology, and End Results database and categorized into three groups: right colon cancer (RCC), left colon cancer (LCC), and rectal cancer (ReC). Adjusted hazard ratios for known predictors of disease-specific survival (DSS) in colorectal cancer were obtained using a Cox proportional hazards regression model.

Results

The study included 57847 patients: 43.5% with RCC, 37.7% with LCC, and 18.8% with ReC. Compared with LCC and ReC, RCC was more likely to affect old patients and women, and to be at advanced stage, poorly differentiated or un-differentiated, and mucinous. Patients with LCC or ReC had better DSS than those with RCC in subgroups including stage III or IV disease, age ≤70 years and non-mucinous adenocarcinoma. Conversely, patients with LCC or ReC had worse DSS than those with RCC in subgroups including age ˃70 years and mucinous adenocarcinoma.

Conclusions

RCC differed from both LCC and ReC in several clinicopathologic characteristics and in DSS. It seems reasonable to group colorectal cancer into right-sided (i.e., proximal) and left-sided (i.e., distal) ones.