Different treatment strategies and molecular features between right-sided and left-sided colon cancers

Impact of prior malignancies on outcome of colorectal cancer; revisiting clinical trial eligibility criteria

Background

Most clinical trials on colorectal cancer (CRC) exclude cases who have history of a prior malignancy. However, no prior research studied this history’s actual impact on the survival of CRC. In the paper, we study the effects of having a malignancy preceding CRC diagnosis on its survival outcomes.

Methods

CRC patients diagnosed during 1973–2008 were reviewed using the SEER 18 database. We calculated overall survival and cancer-specific survival of subsequent CRC, and more specifically stage IV CRC, using Kaplan-Meier test and adjusted Cox models.

Results

A total 550,325 CRC patients were reviewed, of whom 31,663 had history of a prior malignancy. The most commonly reported sites of a prior malignancy were: prostate, breast, urinary bladder, lung, and endometrium. Patients with history of a prior non-leukemic malignancy or history of a prior leukemia were found to have worse overall survival (HR = 1.165 95%CI = 1.148–1.183, P < 0.001) and (HR = 1.825 95%CI = 1.691–1.970, P < 0.001), respectively. However, CRC patients with history of a prior non-leukemic malignancy showed an improved colorectal cancer-specific survival (HR = .930 95%CI = .909–.952, P < 0.001). Analysis of stage IV CRC patients showed that patients with history of any non-leukemic malignancy did not have a significant change in overall survival. Whereas, patients with a prior leukemia showed a worse overall survival (HR = 1.535, 95%CI = 1.303–1.809, P < 0.001). When analyzed separately, right CRC and left CRC showed similar survival patterns.

Conclusion

A prior malignancy before CRC -in general- can be associated with worse clinical survival outcomes. These worse outcomes are not observed in stage IV CRC. Considering these results when including/excluding stage IV CRC patients with prior malignancies in clinical trials may play help improve their generalizability.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-6074-6) contains supplementary material, which is available to authorized users.

Analysis of clinicopathological features and prognosis of 1315 cases in colorectal cancer located at different anatomical subsites

PURPOSE

Compare and analyze the clinicopathological features and prognosis of 1315 patients with colorectal cancer located at different anatomical subsites.

METHODS

A retrospective study was conducted to analyze the clinicopathological features and prognosis from 1315 patients with colorectal cancer who underwent surgery in the department of gastrointestinal surgery at the Second Affiliated Hospital of Dalian Medical University from January 2013 to January 2019. Among them, 287 patients were divided into the right-sided colon cancer (RCC) group; 329 patients were included into the left-sided colon cancer (LCC) group and the remaining 699 patients were assigned to the rectal cancer (RC) group. Clinicopathological features such as gender, age, pathological differentiation, neurovascular invasion, TNM stage, related tumor markers, maximum tumor diameter (MTD), median survival time and overall survival rate were extracted and analyzed.

RESULTS

Patients in the RCC group had the oldest age of onset, highest positive rate of serum CA199 and greatest number of poorly differentiated adenocarcinomas among the three groups and significant statistical differences were found. The RC group had the highest positive rate of vascular invasion (42.9%) and the greatest number of patients in stage I and IV (19% and 3.9%, respectively). Besides, the number of patients with stage T1-T2 adenocarcinoma in RC group was also the highest among the three groups. There were no significant differences in gender, perineural invasion as well as serum levels of CEA, CA724 and CA242. The median survival time of RCC, LCC and RC were 72, 70 and 73 months, respectively, with significant inter-group differences (P = 0.049).

CONCLUSION

The age of onset of right-sided colon cancer is the oldest on average and poorly differentiated tumors accounted for the highest proportion. Besides, average maximum tumor diameter is the largest in right-sided colon cancer. In terms of median survival time, LCC is worse than RCC and RC. Colorectal cancer at different anatomical subsites has different epidemiological, clinicopathological features and prognosis. Fully understanding the clinicopathological features of colorectal cancer at different anatomical subsites is of certain guiding significance for the clinical diagnosis and treatment of colorectal cancer, and is conducive to individualized treatment and accurate treatment.

T Regulatory CD4+CD25+FoxP3+ Lymphocytes in the Peripheral Blood of Left-Sided Colorectal Cancer Patients

Background and objectives: T regulatory lymphocytes (Treg) are one of the subsets of T-lymphocytes involved in the interaction of neoplastic tumors and the host immune system, and they may impair the immune reaction against cancer. It has been shown that Treg are increased in the peripheral blood of patients with various cancers. In colorectal cancer, the prognostic role of Treg remains controversial. Colorectal cancer is a heterogenous disease, with many variations stemming from its primary tumor location. The aim of this study is to analyse the relationship between the amount of Treg in the peripheral blood of patients with left-sided colorectal cancer in various stages of disease and long-term survival. Materials and Methods: A prospective analysis of 94 patients with left-sided colorectal cancer and a group of 21 healthy volunteers was carried out. Treg levels in peripheral blood were analysed using flow cytometry. Results: There was a statistically significant difference between the amount of Treg in the Ist and IInd TNM stages (p = 0.047). The number of Treg in the entire study group was significantly lower than in the control group (p = 0.008) and between patients in stages II and III and the control group (p = 0.003 and p = 0.018). The group of pT3+pT4 patients also had significantly lower Treg counts in their peripheral blood than the control group (p = 0.005). In the entire study group, the level of Treg cells in the peripheral blood had no influence on survival. The analysis of the TNM stage subgroups also showed no difference in survival between patients with “low” and “high” Treg counts. Conclusion: The absolute number of Treg in the peripheral blood of patients with left-sided colorectal cancer was significantly decreased in comparison to healthy controls, especially for patients with stage II+III disease. Treg presence in the peripheral blood had no impact on survival.

The impact of resection margin on overall survival for patients with colon cancer liver metastasis varied according to the primary cancer location

INTRODUCTION

Investigation into right and left-sided primary colon liver metastasis (CLM) has revealed differences in the tumor biology and prognosis. This indicates that preoperative and operative factors may affect outcomes of right-sided primary CLM differently than left. This retrospective analysis investigated the effects of resection margin stratified by left and right-sided primary CLM on overall survival (OS) for patients undergoing hepatectomy.

METHODS

A total of 732 patients undergoing hepatic resection for CLM at the Cleveland Clinic and Johns Hopkins were identified between 2002 and 2016. Clinically significant variables were analyzed using Cox proportional hazard regression. The cohort was then divided into patients with right and left-sided CLM and analyzed separately using Kaplan Meier analysis and Cox proportional hazard regression.

RESULTS

Cox proportional hazard regression showed that left-sided CLM with an R0 margin was a statistically significant predictor of OS even after controlling for other important factors (HR = 0.629, P = 0.024) but right-sided CLM with R0 margin was not (HR = 0.788, P = 0.245). Kaplan-Meier analysis demonstrated that patients with a left-sided CLM and R0 margin had the best prognosis (P = 0.037).

CONCLUSION

Surgical margin is an important prognostic factor for left-sided primary CLM but tumor biology may override surgical technique for right-sided CLM.

Primary tumour location affects survival after resection of colorectal liver metastases: A two-institutional cohort study with international validation, systematic meta-analysis and a clinical risk score

BACKGROUND

Colorectal cancer (CRC) represents a major cause for cancer death and every third patient develops liver metastases (CRLM). Several factors including number and size of metastases and primary tumour lymph-node status have been linked to survival. The primary tumour location along the colo-rectum continuum (sidedness) was analysed in first-line chemotherapy trials, where right-sided CRCs showed decreased survival. This association has not yet been clearly established in patients undergoing resection for CRLM.

METHODS

Clinicopathological differences in CRLM resections according to sidedness in two Austrian centres (2003-2016) are described and survival is compared through Kaplan-Meier and multivariable analysis. A risk-score is presented with time-dependent receiver operating curve analysis and international validation in two major hepatobiliary centres. Furthermore, a systematic meta-analysis of studies on primary tumour location and survival after CRLM resection was performed.

RESULTS

259 patients underwent hepatectomy. Right-sided CRC patients (n = 59) more often had positive primary tumour lymph-nodes (76.3%/61.3%;p = 0.043) and RAS-mutations (60%/34.9%;p = 0.036). The median overall and disease-free survival was 33.5 and 9.1 months in right-sided versus 55.5 (p = 0.051) and 12.1 months (p = 0.078) in left-sided patients. In multivariable analysis nodal-status (HR 1.52), right-sidedness (HR 1.53), extrahepatic disease (HR 1.71) and bilobar hepatic involvement (HR 1.41) were significantly associated with overall survival. Sidedness was not independently associated with disease-free survival (HR 1.33; p = 0.099). A clinical risk score including right-sidedness, nodal-positivity and extrahepatic involvement significantly predicted overall (p = 0.005) and disease-free survival (p = 0.027), which was confirmed by international validation in 527 patients (p = 0.001 and p = 0.011). Meta-analysis including 10 studies (n = 4312) showed a significant association of right-sidedness with overall survival after resection (HR 1.55;p<0.001). There was no significant association with disease-free survival (HR 1.22;p = 0.077), except when rectal-cancers were excluded (HR 1.39;p = 0.006).

CONCLUSIONS

Patients with liver metastases from right-sided CRC experience worse survival after hepatic resection. Sidedness is a simple yet effective factor to predict outcome.

Sidedness of Colorectal Cancer Impacts Risk of Second Primary Gastrointestinal Malignancy

INTRODUCTION

A history of colorectal cancer (CRC) increases the risk of subsequent gastrointestinal (GI) cancer. Cancers of the right colon, left colon, and rectum differ according to molecular profiles, responses to treatment, and outcomes.

OBJECTIVE

The purpose of this study was to determine if CRC location is associated with differential risk for secondary primary GI malignancy.

METHODS

A retrospective cohort of adults with CRC was compiled using the Surveillance, Epidemiology, and End Results database (1973-2015). Standardized incidence ratios (SIRs) for second primary GI malignancies were compared based on location of the index CRC (right colon, left colon, or rectum).

RESULTS

The cohort included 281,413 adults with CRC (30.3% right, 35.3% left, 34.3% rectum). With a median 4.9-year follow-up, 12,064 (4.3%) patients developed a second primary GI malignancy (64% CRC, 36% non-CRC). Those with CRC at any location had higher than expected incidences of small intestine, bile duct, and other CRCs, and lower incidences of liver and gallbladder cancer. The SIR for small intestinal cancer was higher after right colon cancer than after left colon or rectal cancer. The esophageal cancer SIR was higher after left colon cancer. Pancreas cancer was higher than expected for right colon cancer, but lower for left colon and rectal cancer.

CONCLUSION

The location of CRC leads to differences in the incidence and location of second primary GI malignancies and may be related to similarities in the associated carcinogenesis and molecular pathways or response to treatment. CRC location not only impacts treatment response and outcomes, but should also be considered during subsequent surveillance.

A Statistical Analysis of Risk Groups in Colorectal Cancer Patients

Colorectal cancer (CRC) is considered a major global health concern due to an increasing number of new cases and cancer-related deaths each year, strong link to dietary habits prevalent in middle and high-income countries and limited therapeutic options especially in locally-advanced and metastatic settings. To counter this growing problem, the scientific community has strived to underpin the major molecular mechanisms behind the aggressive phenotype displayed by CRC and also develop new agents to selectively target and inhibit these core drivers. This evolution has allowed the separation of patients according to different risk groups in concordance with epidemiological parameters alongside novel biomarkers such as gene alterations, protein overexpression and aberrant signaling pathways. In this study we included 20 patients who underwent colonoscopy and were later received histopathologic confirmation of CRC. The statistical anamnestic data obtained from the patients (age, gender, home distribution, signs and symptoms) was corroborated with the results obtained from the histopathologic and immunohistochemical analysis of the samples obtained via colonoscopy. The average age was 63.8 years, the male: female ratio was 2.33 and the origin of 2/3 of the patients was urban and the most encountered symptoms were transit disorders (75%). In terms of colonoscopy results, the majority of tumors were found on the rectum (85%), 90% of tumors were adenocarcinomas, having a vegetant aspect in 60% of the cases and a moderate degree of differentiation in 50% of situations.

Long-term outcomes after surgical resection in patients with stage IV colorectal cancer: a retrospective study of 129 patients at a single institution

Background and purpose

Approximately 20% of all patients with colorectal cancer (CRC) are diagnosed at more advanced stages with synchronous distant metastasis, and the prognosis in these patients is usually poor. The aim of this study was to determine the factors that can identify subgroup(s) of patients with stage IV CRC who could benefit from curative (R0) resection of both primary and metastatic lesions.

Patients and methods

A total of 126 patients with stage IV CRC who underwent surgical resection of primary tumor were retrospectively analyzed. Among these patients, 26 cases of R0 resection were further examined subsequently. Information on various clinicopathological factors of the patients were obtained from hospital records. Overall survival was estimated using the Kaplan-Meier method, and log-rank tests were used to compare survival distribution. All the factors with P < 0.05 in univariate analysis were analyzed in the Cox proportional hazards model.

Results

CEA negativity, left-sided tumor, R0 resection, differentiated histology, and nodal staging less than N1 were independent factors that predicted better prognosis in all the 126 patients with stage IV CRC. Tumor depth of T3 or less was significantly correlated with better survival in patients who had undergone R0 resection.

Conclusion

Our findings demonstrate that it is possible to select patients in whom surgical resection would yield better prognosis, from a variety of patient subgroups with stage IV CRC.

Clinicopathological and molecular differences in colorectal cancer according to location

PURPOSE

The incidence, pathogenesis, molecular pathways, and outcomes of colorectal cancer vary depending on the location of the tumor. This study aimed to compare the difference in tumor characteristics and the outcome between right-sided colon cancer and left-sided colorectal cancer (LCRC).

MATERIALS AND METHODS

A total of 1503 patients with colorectal cancer who underwent surgery at the Taipei Veterans General Hospital between 2000 and 2010 were enrolled in this study. Right-sided colon cancer was defined as cancers in the cecum, ascending colon, and transverse colon, while LCRC was defined as cancers in the splenic flexure colon, descending colon, sigmoid colon, and rectum. The endpoint was overall survival. The mutations were detected via polymerase chain reaction and MASS array. The prognostic value was determined using the log-rank test and the Cox regression analysis.

RESULTS

A total of 407 and 1096 cases were classified as right-sided colon cancer and LCRC, respectively. Compared to patients with LCRC, those with right-sided colon cancer had more mucinous type cancer (7.4% vs. 3.5%), poorly differentiated tumor (11.5% vs. 3.6%), and advanced tumor-node-metastasis stage. The risk for peritoneal tumor seeding was higher in the right-sided colon cancer group (12.8% vs. 5.7%). Overall survival was better in LCRC than in right-sided colon cancer ( P=0.036).

CONCLUSIONS

In our study, right-sided colon cancer had a more advanced tumor stage, a higher risk of peritoneal metastasis, and a poorer outcome than LCRC. Moreover, right-sided colon cancer had more gene mutations in BRAF, KRAS, SMAD4, TGF-β, PIK3CA, PTEN, AKT1, and high microsatellite instability.

Does the Different Locations of Colon Cancer Affect the Oncologic Outcome? A Propensity-Score Matched Analysis

PURPOSE

We evaluate the prognostic value of primary tumor location for oncologic outcomes in patients with colon cancer (CC).

METHODS

CC patients treated with curative surgery between 2009 and 2012 were classified into 2 groups: right-sided colon cancer (RCC) and left-sided colon cancer (LCC). Recurrence-free survival (RFS) and overall survival (OS) were examined based on tumor stage. Propensity scores were created using eight variables (age, sex, T stage, N stage, histologic grade, presence of lymphovascular invasion/perineural invasion, and microsatellite instability status).

RESULTS

Overall, 2,329 patients were identified. The 5-year RFSs for RCC and LCC patients were 89.7% and 88.4% (P = 0.328), respectively, and their 5-year OSs were 90.9% and 93.4% (P = 0.062). Multivariate survival analyses were carried out by using the Cox regression proportional hazard model. In the unadjusted analysis, a marginal increase in overall mortality was seen in RCC patients (hazard ratio [HR], 1.297; 95% confidence interval [CI], 0.987-1.704, P = 0.062); however, after multivariable adjustment, similar OSs were observed in those patients (HR, 1.219; 95% CI, 0.91-1.633; P = 0.183). After propensity-score matching with a total of 1,560 patients, no significant difference was identified (P = 0.183). A slightly worse OS was seen for stage III RCC patients (HR, 1.561; 95% CI, 0.967-2.522; P = 0.068) than for stage III LCC patients. The 5-year OSs for patients with stage III RCC and stage III LCC were 85.5% and 90.5%, respectively (P = 0.133).

CONCLUSION

Although the results are inconclusive, tumor location tended to be associated with OS in CC patients with lymph node metastasis, but it was not related to oncologic outcome.

Impact of primary tumor location as a predictive factor in patients suffering from colorectal cancer treated with cytotoxic anticancer agents based on the collagen gel droplet-embedded drug sensitivity test

In recent studies, better clinical outcomes for patients with left-sided colon cancer (CC) compared with right-sided CC have been reported; however, in such investigations, the chemotherapy regimens included molecular-targeting agents. To the best of our knowledge, the impact of primary tumor location as a predictive factor in patients suffering from CC treated with cytotoxic anticancer agents alone has not been investigated. The aim of the present study was to determine the impact of the primary tumor location as a predictive factor of patients undergoing the following cytotoxic anticancer agent regimens: Leucovorin and fluorouracil + oxaliplatin (FOLFOX) or Leucovorin and fluorouracil + irinotecan (FOLFIRI), using the collagen gel droplet-embedded drug sensitivity test (CD-DST). Between March 2008 and April 2017, tumor specimens were obtained from 133 patients suffering from colorectal cancer (CRC) who had not received preoperative chemotherapy. CD-DST was performed and the growth inhibition rate (IR) was determined in FOLFOX and FOLFIRI regimens. The associations between tumor location and IR values for each condition were evaluated. In the present study, the prognosis of patients receiving palliative chemotherapy as well as treatment with molecularly-targeted agents was also investigated. There were no significant differences in the IRs (%) of the two regimens using CD-DST for right-sided tumors compared with left-sided tumors, including or excluding the rectum. The median survival times of patients with right CC and left CC who had received palliative chemotherapy and treatment with molecularly-targeted agents were 960 and 1,348 days, respectively. Primary tumor location did not represent a predictive factor for the efficacy of treatment with cytotoxic anticancer agent regimens using CD-DST. However, patients suffering from left-sided CC were revealed to exhibit better clinical outcomes compared with patients suffering from right-sided CC when molecularly-targeted agent regimens were administered. Therefore, the results of the present study suggested that molecularly-targeted agents rather than cytotoxic anticancer agents may result in improved clinical outcomes for patients with CRC suffering from left-sided tumors.

CD44v6 engages in colorectal cancer progression

CD44 is a transmembrane glycoprotein. When the CD44 gene is expressed, its pre-messenger RNA (mRNA) can be alternatively spliced into mature mRNAs that encode several CD44 isoforms. The mRNA assembles with ten standard exons, and the sixth variant exon encodes CD44v6, which engages in a variety of biological processes, including cell growth, apoptosis, migration, and angiogenesis. Mechanistically, CD44v6 interacts with hyaluronic acid (HA) or osteopontin, or it acts as a coreceptor for various cytokines, such as epidermal growth factor, vascular endothelial growth factor, hepatocyte growth factor, and C-X-C motif chemokine 12. In this context, the receptor tyrosine kinase or G protein-coupled receptor-associated signaling pathways, including mitogen-activated protein kinase/extracellular-signal-regulated kinase and phosphoinositide-3-kinase/Akt, are activated. Using these actions, homeostasis or regeneration can be facilitated among normal tissues. However, overexpression of the mature mRNA encoding CD44v6 can induce cancer progression. For example, CD44v6 assists colorectal cancer stem cells in colonization, invasion, and metastasis. Overexpression of CD44v6 predicts poor prognosis in patients with colorectal cancer, as patients with a large number of CD44v6-positive cells in their tumors are generally diagnosed at late stages. Thus, the clinical significance of CD44v6 in colorectal cancer deserves consideration. Preclinical results have indicated satisfactory efficacies of anti-CD44 therapy among several cancers, including prostate cancer, pancreatic cancer, and gastric cancer. Moreover, clinical trials aiming to evaluate the pharmacokinetics, pharmacodynamics, efficacy, and toxicity of a commercialized anti-CD44 monoclonal antibody developed by Roche (RO5429083) have been conducted among patients with CD44-expressing malignant tumors, and a clinical trial focusing on the dose escalation of this antibody is ongoing. Thus, we are hopeful that anti-CD44 therapy will be applied in the treatment of colorectal cancer in the future.

Differences Regarding the Molecular Features and Gut Microbiota Between Right and Left Colon Cancer

For many years, developmental and physiological differences have been known to exist between anatomic segments of the colorectum. Because of different outcomes, prognoses, and clinical responses to chemotherapy, the distinction between right colon cancer (RCC) and left colon cancer (LCC) has gained attention. Furthermore, variations in the molecular features and gut microbiota between right and LCCs have recently been a hot research topic. CpG island methylator phenotype-high, microsatellite instability-high colorectal cancers are more likely to occur on the right side whereas tumors with chromosomal instability have been detected in approximately 75% of LCC patients and 30% of RCC patients. The mutation rates of oncogenes and tumor suppressor genes also differ between RCC and LCC patients. Biofilm is more abundant in RCC patients than LLC patients, as are Prevotella, Selenomonas, and Peptostreptococcus. Conversely, Fusobacterium, Escherichia/Shigella, and Leptotrichia are more abundant in LCC patients compared to RCC patients. Distinctive characteristics are apparent in terms of molecular features and gut microbiota between right and LCC. However, how or to what extent these differences influence diverging oncologic outcomes remains unclear. Further clinical and translational studies are needed to elucidate the causative relationship between primary tumor location and prognosis.

Female Sex and Right-Sided Tumor Location Are Poor Prognostic Factors for Patients With Stage III Colon Cancer After a Curative Resection

Purpose

Stage-IIIC colon cancer is an advanced disease; however, its oncologic outcomes and prognostic factors remain unclear. In this study, we aimed to determine the predictors of disease-free survival (DFS) in patients with stage-IIIC colon cancer.

Methods

From a multicenter database, we retrospectively enrolled 611 patients (355 men and 256 women) who had undergone a potentially curative resection for a stage-IIIC colon adenocarcinoma between 2003 and 2011. The primary end-point was the 5-year DFS.

Results

The median age was 62 years; 213 and 398 patients had right-sided colon cancer (RCC) and left-sided colon cancer (LCC), respectively. The 5-year DFS in all patients was 52.0%; median follow-up time was 35 months (range, 1–134 months). A multivariate Cox regression revealed that female sex (hazard ratio [HR], 1.50; 95% confidence interval [CI], 1.19–1.90; P < 0.01), right-sided tumor location (HR, 1.65; 95% CI, 1.29–2.11; P < 0.01), lymphatic invasion (HR, 1.52; 95% CI, 1.08–2.15; P < 0.01) and a high (≥0.4) metastatic lymph node ratio (HR, 3.72; 95% CI, 2.63–5.24; P < 0.01) were independent predictors of worse 5-year DFS. Female patients with RCC were 1.79 fold more likely to experience recurrence than male patients with LCC.

Conclusion

Female sex and right-sided tumor location are associated with higher tumor recurrence rates in patients with stage-IIIC colon cancers. Aggressive treatment and close surveillance should be planned for patients in these groups.

Metabolomics and 16S rRNA sequencing of human colorectal cancers and adjacent mucosa

Colorectal cancer (CRC) is ranked the third most common cancer in human worldwide. However, the exact mechanisms of CRC are not well established. Furthermore, there may be differences between mechanisms of CRC in the Asian and in the Western populations. In the present study, we utilized a liquid chromatography-mass spectrometry (LC-MS) metabolomic approach supported by the 16S rRNA next-generation sequencing to investigate the functional and taxonomical differences between paired tumor and unaffected (normal) surgical biopsy tissues from 17 Malaysian patients. Metabolomic differences associated with steroid biosynthesis, terpenoid biosynthesis and bile metabolism could be attributed to microbiome differences between normal and tumor sites. The relative abundances of Anaerotruncus, Intestinimonas and Oscillibacter displayed significant relationships with both steroid biosynthesis and terpenoid and triterpenoid biosynthesis pathways. Metabolites involved in serotonergic synapse/ tryptophan metabolism (Serotonin and 5-Hydroxy-3-indoleacetic acid [5-HIAA]) were only detected in normal tissue samples. On the other hand, S-Adenosyl-L-homocysteine (SAH), a metabolite involves in methionine metabolism and methylation, was frequently increased in tumor relative to normal tissues. In conclusion, this study suggests that local microbiome dysbiosis may contribute to functional changes at the cancer sites. Results from the current study also contributed to the list of metabolites that are found to differ between normal and tumor sites in CRC and supported our quest for understanding the mechanisms of carcinogenesis.

Impact of primary tumor location as a predictive factor in patients suffering from colorectal cancer treated with cytotoxic anticancer agents based on the collagen gel droplet-embedded drug sensitivity test

In recent studies, better clinical outcomes for patients with left-sided colon cancer (CC) compared with right-sided CC have been reported; however, in such investigations, the chemotherapy regimens included molecular-targeting agents. To the best of our knowledge, the impact of primary tumor location as a predictive factor in patients suffering from CC treated with cytotoxic anticancer agents alone has not been investigated. The aim of the present study was to determine the impact of the primary tumor location as a predictive factor of patients undergoing the following cytotoxic anticancer agent regimens: Leucovorin and fluorouracil + oxaliplatin (FOLFOX) or Leucovorin and fluorouracil + irinotecan (FOLFIRI), using the collagen gel droplet-embedded drug sensitivity test (CD-DST). Between March 2008 and April 2017, tumor specimens were obtained from 133 patients suffering from colorectal cancer (CRC) who had not received preoperative chemotherapy. CD-DST was performed and the growth inhibition rate (IR) was determined in FOLFOX and FOLFIRI regimens. The associations between tumor location and IR values for each condition were evaluated. In the present study, the prognosis of patients receiving palliative chemotherapy as well as treatment with molecularly-targeted agents was also investigated. There were no significant differences in the IRs (%) of the two regimens using CD-DST for right-sided tumors compared with left-sided tumors, including or excluding the rectum. The median survival times of patients with right CC and left CC who had received palliative chemotherapy and treatment with molecularly-targeted agents were 960 and 1,348 days, respectively. Primary tumor location did not represent a predictive factor for the efficacy of treatment with cytotoxic anticancer agent regimens using CD-DST. However, patients suffering from left-sided CC were revealed to exhibit better clinical outcomes compared with patients suffering from right-sided CC when molecularly-targeted agent regimens were administered. Therefore, the results of the present study suggested that molecularly-targeted agents rather than cytotoxic anticancer agents may result in improved clinical outcomes for patients with CRC suffering from left-sided tumors.

Colorectal Cancer: Why Does Side Matter?

Colorectal cancer (CRC) is a heterogeneous disease, and the search for clinical and molecular prognostic and predictive factors is thus necessary to better tailor each individual patient's management. Primary tumor location (PTL) seems to act as a master prognostic factor pooling different clinical, pathological, and molecular poor prognostic factors. In fact, right-sided (RS) CRC patients are more frequently female and elderly with microsatellite unstable, BRAF mutated, CpG island methylator phenotype (CIMP)-high, poorly differentiated tumors, compared to left-sided (LS) CRC patients. PTL does not seem to clearly influence disease-free survival (DFS) in localised colon cancer even though the opposite prognostic value of RS tumors on DFS depending on RAS/BRAF mutational status has been recently suggested in these patients. In metastatic CRC (mCRC), the poor prognosis associated with RS tumors is confirmed in the most recent publications in the era of double and triple chemotherapeutic regimens and targeted agents. Concerning the predictive value of PTL, in patients with RAS wild-type mCRC in the first-line setting, anti-epidermal growth factor receptor (EGFR) therapy combined with chemotherapy appears to be more effective than bevacizumab in LS CRC, while patients with RS CRC benefit less from anti-EGFR therapy, and intensive chemotherapy plus bevacizumab may be more appropriate but EGFR antibodies remain an option if objective response is needed. Due to the limitation of the current data (unplanned and retrospective analyses), these conclusions must be interpreted with caution. Clinical trials in RS CRC may be of interest to clarify what is the best treatment strategy in these patients.

Differences in overall survival and mutation prevalence between right- and left-sided colorectal adenocarcinoma

Background

Prior reports have demonstrated inferior outcomes for patients with right-sided colorectal cancer (CRC) compared to patients with left-sided disease, as well as differences in treatment response based on disease sidedness. Differences in prognosis remain even among patients with metastatic disease, indicating that anatomy or stage at diagnosis alone cannot explain all of these findings. While genetic differences between right- and left-sided CRC have long been described, the genetic and molecular drivers underlying differences in prognosis and treatment response remain incompletely understood.

Methods

We compared mutation prevalence between right- (cecum to splenic flexure) and left-sided (descending colon to rectum) CRC among 38 genes in a retrospective review of next-generation sequencing data of CRC samples obtained in routine clinical practice at a single academic medical center.

Results

Among 288 cases (167 left-sided, 103 right-sided, 18 synchronous or without clear primary), patients with left-sided primaries had a longer overall survival from pathologic diagnosis (median 1,823 days vs. 1,006 days for right-sided cases, P=0.004). Among the assessed genes, BRAF and CTNNB1 mutations were more prevalent in right-sided CRC. BRAF was mutated in 15.5% of right-sided CRC (95% CI: 8.5-22.5%) compared to 4.8% (95% CI: 1.6-8.0%) (P=0.003). CTNNB1 was mutated in 3.9% of right-sided CRC (95% CI: 0.2-7.6%) compared to no instances of CTNNB1 mutations in left-sided disease (P=0.01).

Conclusions

This difference in mutation prevalence may implicate these genetic pathways in the mechanisms underlying the discrepant outcomes and treatment responses between right- and left-sided CRC described in this and prior studies.

High Oct4 predicted worse prognosis of right-sided colon cancer patients

Aim: This present study was aimed to compare the role of Oct4 in left-sided colon cancer (LCC) with right-sided colon cancer (RCC). Patients & methods: One hundred and fifty one pathology specimens, 68 frozen-thawed tumors and cell lines were used to evaluate the role of Oct4 in LCC and RCC through immunohistochemistry, western blot and real-time quantitative PCR. Results: In LCC, positive expression of Oct4 was positively related to differentiation and Dukes stage (p < 0.01). Only in RCC, Oct4 expression was also positively related to lymphatic invasion and survival rates of ‘negative group’ were significantly higher. Conclusion: In summary, Oct4 was related to tumor differentiation and later Dukes stage in colon cancer, and was correlated with invasion of lymphatic only in RCC. In addition, Oct4 was a potential prognostic indicator in RCC.

Characteristics and Survival of Korean Patients With Colorectal Cancer Based on Data From the Korea Central Cancer Registry Data

Purpose

The incidence of colorectal cancer (CRC) in Korea has increased remarkably during the past few decades. The present study investigated the characteristics and survival of patients with CRC in Korea as a function of time, tumor distribution, stage, sex, and age.

Methods

We retrieved clinical data on 326,712 CRC patients diagnosed between 1996 and 2015 from the Korea Central Cancer Registry. The incidence and the 5-year relative survival rates were compared across time period, tumor distribution, stage, sex, and age group.

Results

The percentage of patients with colon cancer increased from 49.5% in 1996–2000 to 66.4% in 2011–2015 while the percentage of patients with rectal cancer decreased from 50.5% to 33.6%. The 5-year relative survival rates for all CRCs improved from 58.7% in 1996–2000 to 75.0% in 2011–2015. For 1996–2000, survival rates were highest for patients with left-sided colon cancers, followed by those with right-sided, transverse, rectal, rectosigmoid cancers. For 2011–2015, the survival rates for patients with left-sided cancers were highest, followed by those with rectosigmoid, rectal, transverse, and right-sided colon cancers. Patients with local and regional, but not distant, SEER (Surveillance, Epidemiology, and End Results) stage tumors experienced significantly increased survival rates for 2006–2010 and 2011–2015. The proportion of CRC patients by age decreased in the order ≥70, 60–69, 50–59, 40–49, ≤39 years whereas survival rates decreased in the order 50–59, 60–69, 40–49, ≤39, ≥70 years.

Conclusion

Korean CRC has some distinct characteristics and survival patterns in terms of tumor distribution, stage, sex, and age. With time, survival outcomes have improved for both local and regional, but not distant, stage tumors.

Do Patients with Second Primary Colorectal Cancer Hold the Similar Prognosis and Therapeutic Benefits as Those with Initial Primary Colorectal Cancer?

Aim

The objective is to compare the differences on prognosis and the therapeutic benefits between initial and second primary colorectal cancer (pCRC).

Methods

A dataset containing 377,271 initial pCRC cases and 18,617 second pCRC cases from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) 1988-2015 was evaluated. Survival comparisons were made using the log-rank test. Cox proportional hazards models were used to assess the survival benefits.

Results

The cancer-specific survival rate of patients with initial pCRC was significantly higher than that of patients with second pCRC (5-years survival rate: 64.85% vs. 60.22%, P<0.001). The Chi-square of stratified log rank for age at diagnosis was lower than that for primary site, pTNM stage, sex, race, histology, and grade (Chi-square=86.73). There were almost no differences on therapeutic benefits between patients with initial and second pCRC except that treatments with chemotherapy were significantly associated with longer survival rate compared with treatments without chemotherapy among stage III surgical initial and second primary left-sided colon cancers patients (HR=0.764 vs. 0.581; P for interaction =0.008).

Conclusion

Patients with second pCRC have worse prognosis than those with initial pCRC primarily because of older age in the former group. The results evidenced that the therapeutic benefits on the prognosis for colorectal cancer were generally similar between patients with initial and second pCRC.

Difference between right and left colorectal cancer

Colorectal cancer (CRC) is one of the most common malignant tumors around the world. The incidence of CRC has increasing, but the prognosis is quite different. In recent years, the impact of tumor site on the treatment and prognosis of CRC has attracted widespread attention, and the research for differences between tumors provides a theoretical basis for precise treatment. This review aims to summarize the difference between right and left CRC.

KRAS Testing, Tumor Location, and Survival in Patients With Stage IV Colorectal Cancer: SEER 2010-2013

Purpose:KRAS mutations and tumor location have been associated with response to targeted therapy among patients with stage IV colorectal cancer (CRC) in various trials. This study performed the first population-based examination of associations between KRAS mutations, tumor location, and survival, and assessed factors associated with documented KRAS testing. Methods: Patients with stage IV adenocarcinoma of the colon/rectum diagnosed from 2010 to 2013 were extracted from SEER data. Analyses of patient characteristics, KRAS testing, and tumor location were conducted using logistic regression. Cox proportional hazards models assessed relationships between KRAS mutations, tumor location, and risk of all-cause death. Results: Of 22,542 patients, 30% received KRAS testing, and 44% of these had mutations. Those tested tended to be younger, married, and metropolitan area residents, and have private insurance or Medicare. Rates of KRAS testing also varied by registry (range, 20%-46%). Patients with right-sided colon cancer (vs left-sided) tended to be older, female, and black; have mucinous, KRAS-mutant tumors; and have a greater risk of death (hazard ratio [HR], 1.27; 95% CI, 1.22-1.32). KRAS mutations were not associated with greater risk of death in the overall population; however, they were associated with greater risk of death among patients with left-sided colon cancer (HR, 1.19; 95% CI, 1.05-1.33). Conclusions: This large population-based study showed that among patients initially diagnosed with stage IV CRC, right-sided colon cancer was associated with greater risk of death compared with left-sided cancer, and KRAS mutations were only associated with risk of death in left-sided colon cancer. An unexpected finding was that among patients with stage IV disease, right-sided cancer was more commonly seen in black patients versus whites. Future studies should further explore these associations and determine the role of biology versus treatment differences. In addition, use of KRAS testing is increasing, but there is wide geographic variation wherein disparities related to insurance coverage and rurality may warrant further study.

Right- and left-sided stage III colon cancers present different prognostic outcomes of oxaliplatin-based adjuvant chemotherapy after curative resection

Background

Growing evidence has suggested that right-sided colon cancer (RCC) and left-sided colon cancer (LCC) should be considered as different tumor entities. However, stage III colon cancer is currently treated as the same entity with uniform therapy. This study was aimed at investigating the prognostic influence of tumor location in patients with stage III colon cancer receiving adjuvant chemotherapy after curative resection.

Patients and methods

We retrospectively analyzed 274 eligible patients with stage III colon cancer undergoing curative tumor resection followed by adjuvant chemotherapy with oxaliplatin and capecitabine between December 2007 and December 2013. Disease-free survival (DFS) and overall survival (OS) were analyzed using Kaplan–Meier and log-rank tests, and prognostic factors were identified by Cox regression methods.

Results

Patients with RCC exhibited lower hemoglobin levels (23.6% vs. 9.8%; P = 0.002), larger tumor size (60.6% vs. 40.9%; P = 0.001), and a higher proportion of 12 or more resected lymph nodes (86.4% vs. 64.6%; P < 0.001) than patients with LCC. Grade 1 neurotoxicity was more common in patients with RCC than in those with LCC (53.6% vs. 40.9%; P = 0.037). RCC was significantly associated with a shorter 3-year OS than LCC, whereas a difference was noted only for stage IIIC and not stage IIIA or stage IIIB colon cancer. Multivariate analyses revealed that RCC was independently associated with a worse 3-year OS (hazard ratio: 2.213; 95% CI: 1.063–4.606; P = 0.002). In addition, an increase in 3-year OS and DFS after 6–8 cycles of adjuvant chemotherapy was only observed in patients with RCC and not in those with LCC.

Conclusion

This study indicated that RCC has a worse prognostic outcome for stage III colon cancer, and a full course of adjuvant chemotherapy should be suggested for patients with RCC.

Disparities in survival for right-sided vs. left-sided colon cancers in young patients: a study based on the Surveillance, Epidemiology, and End Results database (1990-2014)

Purpose

To investigate whether young patients exhibit different characteristics and survival according to tumor location and stage using data from the Surveillance, Epidemiology, and End Results (SEER) database.

Patients and methods

Young patients (20–49 years old) with stage I–III colon cancers were identified from the SEER program from 1990 to 2014. Kaplan–Meier survival analysis and Cox proportional hazards regression were used to analyze the data. Subset analyses were also done among different age and stage subgroups.

Results

Of 8197 patients, 3709 (45.2%) had right-sided colon cancers (RCCs). Patients with RCCs were more likely to be male, to be younger, and to have more poorly differentiated and more advanced tumors. The Kaplan–Meier survival curves and univariate survival models revealed that left-sided colon cancers (LCCs) had lower mortality for all stages combined and stage III, but higher mortality for stage II, compared with right-sided tumors. However, multivariate Cox regression models showed no significant survival differences by location for all patients (adjusted hazard ratio [HR], 0.95; 95% confidence interval [CI], 0.86–1.05; P=0.34) or for stage I (adjusted HR, 1.47; 95% CI, 0.82–2.63; P=0.20). Stage II left-sided cancers had higher mortality (adjusted HR, 1.24; 95% CI, 1.00–1.54; P=0.048), whereas stage III left-sided cancers had lower mortality (adjusted HR, 0.86; 95% CI, 0.77–0.97; P=0.01). For 20- to 39-year-old patients, a significant difference was only found in stage II disease, with a higher mortality for left-sided tumors (adjusted HR, 1.82; 95% CI, 1.12–2.97; P=0.02). However, for 40- to 49-year-old patients, a significant difference was only found in stage III disease, with a lower mortality for left-sided tumors (adjusted HR, 0.83; 95% CI, 0.72–0.95; P=0.008).

Conclusion

In patients younger than 50 years, there were no significant differences in mortality between RCCs and LCCs for all stages combined after adjusting for multiple clinicopathological features. However, RCCs had lower mortality in stage II (especially in 20- to 39-year-old patients) and higher mortality in stage III (especially in 40- to 49-year-old patients).

Serum MMP-8 and TIMP-1 predict prognosis in colorectal cancer

BACKGROUND

Almost all of the extracellular matrix (ECM) components can be degraded by the endoproteinases matrix metalloproteinases (MMPs). Important regulators of MMPs, and thereby of the extracellular environment, are tissue inhibitors of metalloproteinases (TIMPs), and especially TIMP-1. Early tumor development, as well as distant metastasis, may be results of an MMP/TIMP ratio imbalance altering the ECM. MMPs are elevated in several inflammatory conditions. Our aim is to investigate the prognostic role of MMP-8, - 9, and TIMP-1 in colorectal cancer (CRC) and their relationship to inflammation.

METHODS

We included 337 colorectal cancer patients and 47 controls undergoing surgery at Helsinki University Hospital in Finland, 1998-2011. Serum levels of MMP-8 and plasma levels of C-reactive protein (CRP) were determined with a time-resolved immunofluorometric assay (IFMA), and MMP-9 and TIMP-1 with commercial enzyme-linked immunosorbent assay (ELISA) kits. Association and correlation analyses were performed with the Mann-Whitney U, Kruskal-Wallis, and Spearman rank correlation tests. Survival curves were constructed according to the Kaplan-Meier method and compared with the log-rank test.

RESULTS

Among patients with advanced disease, serum levels of MMP-8 and TIMP-1 were elevated. CRC patients with high MMP-8 (HR (hazard ratio) 1.72, 95% confidence interval (CI) 1.17-2.52, P = 0.005) and those with high TIMP-1 (HR 1.80, 95% CI 1.23-2.64, P = 0.002) had worse prognoses. MMP-9 level failed to serve as a prognostic factor. In multivariable survival analysis, Dukes stage, and low MMP-9/TIMP-1 molar ratio (HR 0.46, 95% CI 0.33-0.98, P = 0.042) were independently predicted prognosis. A weak correlation between CRP and MMP-8 (r_S = 0.229, P < 0.001), and TIMP-1 (r_S = 0.280, P < 0.001) was noted. Among patients showing no systemic inflammatory response, MMP-8 (HR 1.66, 95% CI 1.10-2.53, P = 0.017) and TIMP-1 (HR 1.59, 95% CI 1.05-2.42, P = 0.029) were prognostic factors.

CONCLUSIONS

MMP-8 and TIMP-1 in serum, but not MMP-9, identified CRC patients with bad prognosis. Among patients showing no systemic inflammatory response, MMP-8 and TIMP-1 may associate with poor prognosis.

Survivin antagonizes chemotherapy-induced cell death of colorectal cancer cells

Irinotecan (CPT-11) and oxaliplatin (L-OHP) are among the most frequently used drugs against colorectal tumors. Therefore, it is important to define the molecular mechanisms that these agents modulate in colon cancer cells. Here we demonstrate that CPT-11 stalls such cells in the G₂/M phase of the cell cycle, induces an accumulation of the tumor suppressor p53, the replicative stress/DNA damage marker γH2AX, phosphorylation of the checkpoint kinases ATM and ATR, and an ATR-dependent accumulation of the pro-survival molecule survivin. L-OHP reduces the number of cells in S-phase, stalls cell cycle progression, transiently triggers an accumulation of low levels of γH2AX and phosphorylated checkpoint kinases, and L-OHP suppresses survivin expression at the mRNA and protein levels. Compared to CPT-11, L-OHP is a stronger inducer of caspases and p53-dependent apoptosis. Overexpression and RNAi against survivin reveal that this factor critically antagonizes caspase-dependent apoptosis in cells treated with CPT-11 and L-OHP. We additionally show that L-OHP suppresses survivin through p53 and its downstream target p21, which stalls cell cycle progression as a cyclin-dependent kinase inhibitor (CDKi). These data shed new light on the regulation of survivin by two clinically significant drugs and its biological and predictive relevance in drug-exposed cancer cells.

Colorectal cancer survival at an oncologic center in Colombia. A historic cohort study

INTRODUCTION AND AIMS

In Colombia, cancer of the colon is the third most frequent cancer in relation to incidence and mortality. Five-year survival depends on stage at diagnosis, albeit that rate is not known for the country. The aim of the present study was to characterize the overall survival and disease-free survival rates in an adult population with colorectal cancer treated at an oncology center in Medellín, Colombia.

MATERIALS AND METHODS

A retrospective cohort study was conducted. The case records of patients with a histologic diagnosis of colorectal cancer, seen within the time frame of 2011 and 2015, were reviewed. The overall survival and disease-free survival curves were calculated using the Kaplan-Meier method.

RESULTS

A total of 824 (54.9%) patients with cancer of the colon and 676 (45.1%) with cancer of the rectum were treated. Mean patient age was 63.3 years, female sex predominated (56.3%), and 98.1% of the tumors were adenocarcinomas. The majority of the lesions were stage iii (31.9% in the colon and 35.5% in the rectum) at the time of diagnosis. Surgery was the most frequent treatment in the colon (85.2%) and radiotherapy was the most frequent in the rectum (75.4%). Overall survival at the median follow-up (27.3 months) was 66.7% for cancer of the colon and 63.9% for cancer of the rectum. Disease-free survival at the median follow-up (18.6 months in colon and 14.9 in rectum) was 72.5 and 68.9%, respectively.

CONCLUSIONS

The clinical characteristics and treatment of patients were similar to those found in other studies. Two-year survival was higher than in other Colombian reports and 5-year survival was lower than that observed in developed countries.

Individualized predictive signatures for 5-fluorouracil-based chemotherapy in right- and left-sided colon cancer

5‐Fluorouracil (5‐FU)‐based adjuvant chemotherapy (ACT) is widely used for the treatment of colon cancer. Colon cancers with different primary tumor locations are clinically and molecularly distinct, implied through their response to 5‐FU‐based ACT. In this work, using 69 and 133 samples of patients with stage II‐III right‐sided and left‐sided colon cancer (RCC and LCC) treated with post‐surgery 5‐FU‐based ACT, we preselected gene pairs whose relative expression orderings were significantly correlated with the disease‐free survival of patients by univariate Cox proportional hazards model. Then, from the identified prognostic‐related gene pairs, a forward‐stepwise selection algorithm was formulated to search for an optimal subset of gene pairs that resulted in the highest concordance index, referred to as the gene pair signature (GPS). We identified prognostic signatures, 3‐GPS and 5‐GPS, for predicting response to 5‐FU‐based ACT of patients with RCC and LCC, respectively, which were validated in independent datasets of GSE14333 and GSE72970. With the aid of the signatures, the transcriptional and genomic characteristics between the predicted responders and non‐responders were explored. Notably, both in RCC and LCC, the predicted responders to 5‐FU‐based ACT were characterized by hypermutation, whereas the predicted non‐responders were characterized by frequent copy number alternations. Finally, in comparison with the established relative expression ordering‐based signature, which was developed without considering the differences between RCC and LCC, the newly proposed signatures had a better predictive performance. In conclusion, 3‐GPS or 5‐GPS can robustly predict response to 5‐FU‐based ACT for patients with RCC or LCC, respectively, in an individual level.

The impact of microsatellite instability status and sidedness of the primary tumor on the effect of bevacizumab-containing chemotherapy in patients with metastatic colorectal cancer

Purpose: We aimed to evaluate the effect of bevacizumab in metastatic CRC (colorectal cancer) regarding to microsatellite instability (MSI) and the sidedness of the primary tumor.

Materials and Methods: A total of 140 CRC patients were retrospectively analyzed, who received bevacizumab-containing chemotherapy between April 2008 and January 2013. MSI status and Kirsten RSAS (KRAS) mutational status were available in all 140 patients, but BRAF (the gene for the B-type Raf kinase) mutational status was only available in 74 patients (52.9%).

Results: MSI-high (MSI-H) was detected in 4.3% of analyzed patients. Characteristics of patients, with the exception of BRAF mutational status, were generally similar between those with right- (RC) and left-sided colon cancer (LC). Right-sided tumors were significantly associated with a BRAF mutation (p=0.025). In addition, patient characteristics with a microsatellite stable (MSS) tumor were not different from those with an MSI-H tumor. For all 140 patients, the most commonly used regimen with bevacizumab was capecitabine plus oxaliplain (XELOX), irrespective of treatment line, followed by 5-fluorouracil, leucovorin, and irinotecan (FOLFIRI), 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX), intravenous 5-fluorouracil (5-FU) and capecitabine plus irinotecan (XELIRI). There was no significant difference between the MSI-H and MSS groups in treatment efficacy, including response rate (RR) and disease control rate (DCR). There was also no difference in RR and DCR according to the sidedness of the primary tumor. No significant difference in progression-free survival (PFS) was observed between MSI-H and MSS groups (5.93 months vs. 7.37 months; p=0.801) or between LC and RC groups (7.37 months vs. 5.83 months; p=0.801).

Conclusions: The effect of bevacizumab was not different between LC and RC and between MSS and the MSI-H tumors.

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.

D-dimer predicts postoperative recurrence and prognosis in patients with liver metastasis of colorectal cancer

BACKGROUND

Colorectal cancer is common, and its incidence is increasing throughout the world. The liver is a major metastatic site, and colorectal liver metastasis (CRLM) has a poor prognosis. Although liver resection is the most effective therapy for CRLM, postoperative recurrence is common. Thus, prognostic markers for CRLM are greatly needed. D-dimer, a fibrin cleavage product, has been shown to be related to colorectal tumor progression, and is also associated with malignant progression and recurrence in various cancers. Therefore, we evaluated the value of D-dimer in predicting the prognosis in CRLM.

METHODS

We retrospectively evaluated 90 cases of resected CRLM to determine the correlation between D-dimer and patient survival. The cut-off value for D-dimer levels was determined using receiver operating characteristic curve analysis.

RESULTS

Significant differences occurred in the recurrence group with higher D-dimer levels (P = 0.00736*), while the optimal cut-off value was 0.6 µg/mL. High D-dimer levels (≥ 0.6 µg/mL) were associated with poor recurrence-free survival (RFS; P = 0.0000841*) and cancer-specific survival (CSS; P = 0.00615*). In the multivariate analysis, D-dimer correlated with CRLM prognosis and independently predicted RFS (P = 0.0179*).

CONCLUSION

High D-dimer levels were associated with poor RFS and CSS. D-dimer was an independent prognostic factor of RFS. Therefore, D-dimer may help predict recurrence and prognosis in patients with CRLM.

Difference between right-sided and left-sided colorectal cancers: from embryology to molecular subtype

INTRODUCTION

Colorectal cancer is one of the most common malignancies in the world, and it exhibits differences in incidence, pathogenesis, molecular pathways, and outcome depending on the location of the tumor. Differences in the microbiome, clinical characteristics, and chromosomal and molecular characteristics have been reported between the right and left side of the colon. Areas covered: This review focuses on the latest developments in epidemiological and chromosomal and molecular studies, which have enhanced our understanding on the underlying genetic and immunological differences between the right-sided colon and the left-sided colorectum in metastatic colorectal cancer. Expert commentary: The numerous findings regarding differences between right- and left-sided colon cancers should have an impact on colorectal cancer screening and therapy. The location of the colorectal cancer should be considered before group stratification into genetic, clinical, and especially chemotherapy trials. A more tailored approach to colon cancer treatment would be highly desirable if future trials further support the hypothesis of two distinct tumor entities.

Whether regional lymph nodes evaluation should be equally required for both right and left colon cancer

Despite the adequacy of nodal evaluation was gradually improved for colon cancer, the disparity in nodal examination for right colon cancer (RCC) and left colon cancer (LCC) still begs the question of whether 12 nodes is an appropriate threshold for both RCC and LCC. From Surveillance, Epidemiology, and End-Results (SEER) database, we identified 53897 RCC patients and 11822 LCC patients. Compared with LCC patients, RCC patients examined more lymph nodes (18.7 vs 16.3), and more likely to examine ≥12 nodes (P<0.001), whereas RCC patients showed lower rates of node positivity (P<0.001). To balance the nodal disparity between RCC and LCC, we revised the 12-node measure based on different tumor locations. With the X-tile, we determined 15 as the optimal node number for RCC and 11 for LCC. To validate the availability of this revised nodal evaluation, the 5-year cancer specific survival (CSS) was calculated according to the optimal node number in RCC and LCC patients, Cox's regression model were used to further assess the prognostic value of this revised nodal evaluation. The results showed that 5-year CSSs were significantly improved for RCC patients with ≥15 lymph nodes, and also for LCC patients with ≥11 lymph nodes (P<0.001). This revised nodal evaluation could also improve the rate of nodal positivity and long-term survival in both RCC and LCC patients compared with 12-node measure. Therefore, the lymph node examination should be discriminately evaluated for RCC and LCC, instead of using 12-node measure to colon cancer as a whole.

Colorectal cancer liver metastases - a population-based study on incidence, management and survival

BACKGROUND

Colorectal cancer (CRC) is a leading cause of cancer-associated deaths with liver metastases developing in 25-30% of those affected. Previous data suggest a survival difference between right- and left-sided liver metastatic CRC, even though left-sided cancer has a higher incidence of liver metastases. The aim of the study was to describe the liver metastatic patterns and survival as a function of the characteristics of the primary tumour and different combinations of metastatic disease.

METHODS

A retrospective population-based study was performed on a cohort of patients diagnosed with CRC in the region of Stockholm, Sweden during 2008. Patients were identified through the Swedish National Quality Registry for Colorectal Cancer Treatment (SCRCR) and additional information on intra- and extra-hepatic metastatic pattern and treatment were retrieved from electronic patient records. Patients were followed for 5 years or until death. Factors influencing overall survival (OS) were investigated by means of Cox regression. OS was compared using Kaplan-Meier estimations and the log-rank test.

RESULTS

Liver metastases were diagnosed in 272/1026 (26.5%) patients within five years of diagnosis of the primary. Liver and lung metastases were more often diagnosed in left-sided colon cancer compared to right-sided cancer (28.4% versus 22.1%, p = 0.029 and 19.7% versus 13.2%, p = 0.010, respectively) but the extent of liver metastases were more extensive for right-sided cancer as compared to left-sided (p = 0.001). Liver metastatic left-sided cancer, including rectal cancer, was associated with a 44% decreased mortality risk compared to right-sided cancer (HR = 0.56, 95% CI: 0.39-0.79) with a 5-year OS of 16.6% versus 4.3% (p < 0.001). In liver metastatic CRC, the presence of lung metastases did not significantly influence OS as assessed by multivariate analysis (HR = 1.11, 95% CI: 0.80-1.53).

CONCLUSION

The worse survival in liver metastatic right-sided colon cancer could possibly be explained by the higher number of metastases, as well as more extensive segmental involvement compared with left-sided colon and rectal cancer, even though the latter had a higher incidence of liver metastases. Detailed population-based data on the metastatic pattern of CRC and survival could assist in more structured and individualized guidelines for follow-up of patients with CRC.

The effect of the primary tumor location on the survival of colorectal cancer patients after radical surgery

Background and Objectives: Colorectal cancer is one of the most common cancers and the leading cause of cancer-related death worldwide. The impact of the primary tumor location on the prognosis of patients with colorectal cancer has long been a concern, but studies have led to conflicting conclusions. Methods: In total, 465 colorectal cancer patients who received radical surgery were reviewed in this study. Enrolled patients were divided into two groups according to the tumor location. Disease-free survival (DFS) and overall survival (OS) were analyzed via the Kaplan-Meier method. A Cox regression model was employed to evaluate the independent prognostic factors for DFS and OS. Results: The right colorectal cancer (RCC) and left colorectal cancer (LCC) groups comprised 202 and 140 patients, respectively. Univariate and multivariate analyses revealed that the tumor location and TNM stage were independent predictors of DFS and OS. Subgroup analyses by stage demonstrated that there were significant differences in DFS and OS between patients with stage II and III RCC and LCC, but not for those with stage I colorectal cancer. Conclusions: Patients with stage II and III LCC had better survival than those with RCC. However, this improvement in DFS and OS was not observed in patients with stage I colorectal cancer.

Is the Location of the Tumor Another Prognostic Factor for Patients With Colon Cancer?

Purpose

In this study, we investigated both the characteristics of right colon cancer (RTCC) in comparison with those of left colon cancer (LTCC) and the impact of the location of the colon cancer on the prognosis.

Methods

We retrospectively analyzed the cases of 974 patients with nonmetastatic colon cancer who had undergone surgery with a curative intent from January 2001 to December 2011. RTCC was defined as a tumor located proximal to the splenic flexure. The characteristics of RTCC cancer were investigated by using descriptive analyses, and their impacts on the prognosis were assessed by using a Cox multivariate regression.

Results

Compared to LTCC, RTCC showed a female-dominant feature, and an undifferentiated pathology was more frequently observed. The number of lymph nodes retrieved from patients with RTCC was significantly higher than that retrieved from patients with LTCC. During 75 months of follow-up, peritoneal recurrence was more common in patients with RTCC than it was in patients with LTCC, and among the patients with stage III colon cancer, the disease-free and the overall survival rates were significantly worse in patients with RTCC. After adjustments with the other prognostic factors associated with colon cancer had been made, a tumor located at the right colon was found to be independently associated with poor prognosis.

Conclusion

RTCC showed unique clinicopathologic features and was associated with a poorer prognosis.

Primary tumor location predicts poor clinical outcome with cetuximab in RAS wild-type metastatic colorectal cancer

Background

In metastatic colorectal cancer, the location of the primary tumor has been suggested to have biological significance. In this study, we investigated whether primary tumor location affects cetuximab efficacy in patients with RAS wild-type metastatic colorectal cancer.

Methods

Genotyping by the SequenomMassARRAY technology platform (OncoMap) targeting KRAS, NRAS, PIK3CA, and BRAF was performed in tumors from 307 patients who had been given cetuximab as salvage treatment. Tumors with mutated RAS (KRAS or NRAS; n = 127) and those with multiple primary location (n = 10) were excluded. Right colon cancer was defined as a tumor located in the proximal part to splenic flexure.

Results

A total of 170 patients were included in the study (right versus left, 23 and 147, respectively). Patients with right colon cancer showed more mutated BRAF (39.1% vs. 5.4%), mutated PIK3CA (13% vs. 1.4%), poorly differentiated tumor (17.4% vs. 3.4%), and peritoneal involvement (26.1% vs. 8.8%) than those with left colon and rectal cancer. Right colon cancer showed poorer progression-free survival (2.0 vs.5.0 months, P = 0.002) and overall survival (4.1 months and 13.0 months, P < 0.001) than the left colon and rectal cancer. By multivariable analysis, BRAF mutation, right colon primary, poorly differentiated histology, and peritoneal involvement were associated with risk of death.

Conclusions

In RAS wild-type colon cancer treated with cetuximab as salvage treatment, right colon primary was associated with poorer survival outcomes than left colon and rectal cancer.

The predictive value of primary tumor location in patients with metastatic colorectal cancer: A systematic review

Colorectal cancer (CRC) is one of the most frequently diagnosed cancers worldwide. It has been reported that left- and right-sided CRC harbor varying disease characteristics, which leads to a difference in prognosis and response to therapy. Recently, there have been retrospective studies about tumor location in metastatic CRC (mCRC) and its potential to predict the effect of anti-vascular endothelial growth factor and anti-epidermal growth factor receptor (anti-EGFR) therapies. In this review, we provide a comprehensive overview of the latest trials studying the predictive value of primary tumor location in mCRC and discuss biomarkers that might be associated with the differences in treatment response. Although data need to be interpreted with caution due to the absence of randomized trials stratified based on tumor location, patients with left-sided CRC seem to benefit more from anti-EGFR therapy than patients with right-sided CRC. Further clinical trials, stratified for tumor location, are warranted.

Comprehensive genomic sequencing detects important genetic differences between right-sided and left-sided colorectal cancer

OBJECTIVES

Anti-epidermal growth factor receptor (EGFR) therapy has been found to be more effective against left-sided colorectal cancer (LCRC) than right-sided colorectal cancer (RCRC). We hypothesized that RCRC is more likely to harbor genetic alterations associated with resistance to anti-EGFR therapy and tested this using comprehensive genomic sequencing.

MATERIALS AND METHODS

A total of 201 patients with either primary RCRC or LCRC were analyzed. We investigated tumors for genetic alterations using a 415-gene panel, which included alterations associated with resistance to anti-EGFR therapy: TK receptors (ERBB2, MET, EGFR, FGFR1, and PDGFRA), RAS pathway (KRAS, NRAS, HRAS, BRAF, and MAPK2K1), and PI3K pathway (PTEN and PIK3CA). Patients whose tumors had no alterations in these 12 genes, theoretically considered to respond to anti-EGFR therapy, were defined as "all wild-type", while remaining patients were defined as "mutant-type".

RESULTS

Fifty-six patients (28%) and 145 patients (72%) had RCRC and LCRC, respectively. Regarding genetic alterations associated with anti-EGFR therapy, only 6 of 56 patients (11%) with RCRC were "all wild-type" compared with 41 of 145 patients (28%) with LCRC (P = 0.009). Among the 49 patients who received anti-EGFR therapy, RCRC showed significantly worse progression-free survival (PFS) than LCRC (P = 0.022), and "mutant-type" RCRC showed significantly worse PFS compared with "all wild-type" LCRC (P = 0.004).

CONCLUSIONS

RCRC is more likely to harbor genetic alterations associated with resistance to anti-EGFR therapy compared with LCRC. Furthermore, our data shows primary tumor sidedness is a surrogate for the non-random distribution of genetic alterations in CRC.

TRAP1 protein signature predicts outcome in human metastatic colorectal carcinoma

TRAP1 is a HSP90 molecular chaperone upregulated in colorectal carcinomas and involved in control of intracellular signaling, cell cycle, apoptosis and drug resistance, stemness and bioenergetics through co-traslational regulation of a network of client proteins. Thus, the clinical significance of TRAP1 protein network was analyzed in human colorectal cancers. TRAP1 and/or its client proteins were quantified, by immunoblot analysis, in 60 surgical specimens of colorectal carcinomas at different stages and, by immunohistochemistry, in 9 colorectal adenomatous polyps, 11 in situ carcinomas and 55 metastatic colorectal tumors. TRAP1 is upregulated at the transition between low- and high-grade adenomas, in in situ carcinomas and in about 60% of human colorectal carcinomas, being downregulated only in a small cohort of tumors. The analysis of TCGA database showed that a subgroup of colorectal tumors is characterized by gain/loss of TRAP1 copy number, this correlating with its mRNA and protein expression. Interestingly, TRAP1 is co-expressed with the majority of its client proteins and hierarchical cluster analysis showed that the upregulation of TRAP1 and associated 6-protein signature (i.e., IF2α, eF1A, TBP7, MAD2, CDK1 and βCatenin) identifies a cohort of metastatic colorectal carcinomas with a significantly shorter overall survival (HR 5.4; 95% C.I. 1.1-26.6; p=0.037). Consistently, the prognostic relevance of TRAP1 was confirmed in a cohort of 55 metastatic colorectal tumors. Finally, TRAP1 positive expression and its prognostic value are more evident in left colon cancers. These data suggest that TRAP1 protein network may provide a prognostic signature in human metastatic colorectal carcinomas.

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.

Comparison of oncological outcomes of right-sided colon cancer versus left-sided colon cancer after curative resection: Which side is better outcome?

PROPOSE

There are embryological origins, anatomical, histological, genetic, and immunological differences between right-sided colon cancer (RCC) and left-sided colon cancer (LCC). Many studies have sought to determine the survival and prognosis according to tumor location. This study aimed to analyze outcomes between RCC and LCC.

MATERIAL AND METHOD

Between January 2000 and December 2012, data on 414 patients who underwent curative resection for RCC and LCC were retrieved from a retrospective database. Propensity score matching (1:1) was performed and RCC was identified in 207 and LCC in 207 patients.

RESULTS

On average, RCC exhibited a more advanced N stage, increased tumor size, more frequently poorly differentiated tumors, more harvested lymph nodes, and more positivity of lymphovascular invasion than LCC. With a median follow-up of 66.7 months, the 5-year overall survival (OS) rates for RCC and LCC were 82.1% and 88.7%, respectively, (P < .05). The 5-year disease-free survival (DFS) rates were 81.4% (RCC) and 88.3% (LCC; P < .05). In stage III cancers, the DFS rates were 61.1% (RCC) and 81.9% (LCC; P < .05), while the OS rates were 65.6% (RCC) and 78.6% (LCC; P = .056).

CONCLUSION

On the basis of present data, LCC exhibited better survival outcomes than RCC after curative resection. Especially in stage III, LCC showed better oncologic outcomes. Proper specialized treatment related to the location of colon cancer is needed.