Colon cancer in Iceland--a nationwide comparative study on various pathology parameters with respect to right and left tumor location and patients age

Impact of Sidedness of Colon Cancer on Epidemiological, Clinical Presentation, Surgical, Pathological, and Oncologic Outcomes

Aim: The purpose of the study was to identify potential differences between patients with right colon cancer and left colon cancer in epidemiological, clinical presentation, pathological, and surgical results in addition to the impact of the sidedness on disease-free survival (DFS) and overall survival (OS). Method: Patients with a diagnosis of colon cancer stages I-IV between 2010 and 2020 were identified from a prospective database in a tertiary single center. Right and left-sided cancer were compared regarding epidemiological, clinical presentation, pathological, and surgical results. Survival analysis was conducted using the Kaplan-Meier method and adjusted hazard ratios for mortality (OS) and disease-free survival (DFS) were obtained using Cox proportional hazards regression. Results: The right colon group included 82 (31%) patients and the left colon group 182 (69%). After adjusted analysis, RCC presented less bleeding (RP: 0.31; CI: 0.18-0.56; p: 0.0001) and change in bowel habits (RP: 0.60; CI: 0.41-0.87; p: 0.0069). A laparotomy approach was more performed in LCC (RP: 0.64; CI: 0.47-0.86; p: 0.0029). Regarding pathological results, RCC had more poorly differentiated tumors (RP: 0.81; CI: 0.70-0.94; p: 0.05). In the adjusted analysis, there was no difference in survival for right-sided compared to left-sided colon cancer: the hazard ratios were 1.36 (CI 95%: 0.61-3.01; p: 0.4490) for OS and 2.04 (CI: 0.91-4.59; p: 0.0814) for DFS. Conclusions: In this population-based cohort, we found no impact of colon cancer sidedness on OS and DFS. RCC presented less differentiated tumors and LCC presented more bleeding and change in bowel habits.

Comprehensive analysis of alternative splicing signatures in pancreatic head cancer

The correlation between dysregulation of splicing and cancers has been increasingly recognised and confirmed. The identification of valuable alternative splicing (AS) in pancreatic head cancer (PHC) has a great significance. AS profiles in PHC were generated using the data from The Cancer Genome Atlas and TCGASpliceSeq. Then, the NMF clustering method was performed to identify overall survival-associated AS (OS-AS) subtypes in PHC patients. Subsequently, we used least absolute shrinkage and selection operator Cox regression analysis to construct an AS-related risk model. The splicing regulatory network was uncovered by Cytoscape 3.7. A total of 1694 OS-AS events were obtained. The PHC patients were divided into clusters 1 and 2. Cluster 1 had poorer prognosis and lower infiltration of immune cells. Subsequently, a prognostic signature was established that showed good performance in predicting OS and progression-free survival. The risk score of this signature was associated with the unique tumour immunity. Moreover, a nomogram incorporating the risk score and clinicopathological parameters was established. Finally, a splicing factor-AS regulatory network was developed. A comprehensive analysis of the AS events in PHC associated with prognosis and tumour immunity may help provide reliable information to guide individual treatment strategies.

The impact of tumor location on long-term survival outcomes in patients with right-sided colon cancer

BACKGROUND

The oncologic outcomes of right-sided cancers are generally grouped in studies. We hypothesized that tumor location (cecal vs. ascending vs. hepatic flexure) may influence cancer-specific outcomes.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was queried for patients over 18 with non-metastatic, invasive (American Joint Committee on Cancer stage I-III) right-sided adenocarcinoma of the colon from 1988 to 2014 who underwent partial colectomy. Patients were categorized into groups: (1) cecum (2) ascending colon (3) hepatic flexure. Demographic, clinical and pathologic factors were compared between groups. Disease-specific and overall survival were described using the Kaplan-Meier method and compared using the log-rank test. Multivariate Cox regression analysis determined the independent association of primary tumor location.

RESULTS

We identified 167,450 patients. Mean age was 72.2 ± 12.3 years and 54.9% were female. Of these, 81,611, 66,857, and 18,982 had cecal, ascending colon, and hepatic flexure cancers, respectively. Cecal cancers were associated with a lower number of examined nodes but a higher likelihood of nodal positivity. Cecal cancer patients were significantly older, had larger tumors, and higher tumor stage. On univariate analysis, cecal cancers were associated with poorer disease-specific and overall survival (all p values < 0.001). On multivariate analysis controlling for sex, age, tumor size, number of examined nodes and stage, hepatic flexure cancers were associated with worse disease-specific (HR 1.05) and overall survival (HR 1.03).

CONCLUSION

Hepatic flexure cancers are associated with worse survival compared to more proximal colon cancers. The cause is likely multifactorial, including biological and technical factors. More aggressive surgical and multimodal therapy may be considered for hepatic flexure colon cancers.

Colorectal cancer and the blood loss paradox

BACKGROUND

Faecal occult blood (FOB) positivity and iron deficiency anaemia (IDA) are common manifestations of colorectal cancer (CRC) and both potentially facilitate diagnosis at an earlier, more treatable stage. It has been assumed that both are the consequence of low-grade blood loss from the tumour bed.

METHOD

A retrospective analysis of 1121 cases of CRC diagnosed at a single centre between 2010 and 2016, comparing cases presenting via FOB-based Bowel Cancer Screening Programme (BCSP) and IDA pathways for a series of variables including age, sex, tumour location and prevalence of anaemia.

RESULTS

The BCSP and IDA pathways each accounted for about 15% of the total case load. There were significant differences between the BCSP and IDA sub-groups in median age (68 vs 78 years: p<0.001), median haemoglobin (138 vs 89 g/L: p<0.001) and proportion of lesions in right colon (31.1% vs 82.5%: p<0.001). The major disparity in the prevalence of anaemia (overall 20.0% vs 98.2%: p<0.001) persisted when controlled for tumour location.

CONCLUSION

Paradoxically, CRC screening through the detection of FOB positivity and IDA identifies distinctly different sub-populations of cases. The theoretical implication is that an additional mechanism may be required to explain the development of IDA in CRC. The practical implication is that detection of IDA may have a complementary role to the BCSP in population screening for CRC.

Bone-Specific Metastasis Pattern of Advanced-Stage Lung Adenocarcinoma According to the Localization of the Primary Tumor

Background: Patients with advanced-stage lung adenocarcinoma (LADC) often develop distant metastases in the skeletal system. Yet, the bone-specific metastasis pattern is still controversial. We, therefore, aimed to examine how the primary tumor location affects bone specificity and survival in LADC patients diagnosed with skeletal metastases. Methods: In total, 209 bone-metastatic Caucasian LADC patients from two thoracic centers were included in this study. Focusing on the specific location of primary tumors and bone metastatic sites, clinicopathological variables were included in a common database and analyzed retrospectively. Skeletal metastases were diagnosed according to the contemporary diagnostic guidelines and confirmed by bone scintigraphy. Besides region- and side-specific localization, primary tumors were also classified as central or peripheral tumors based on their bronchoscopic visibility. Results: The most common sites for metastasis were the spine (n = 103) and the ribs (n = 60), followed by the pelvis (n = 36) and the femur (n = 22). Importantly, femoral (p = 0.022) and rib (p = 0.012) metastases were more frequently associated with peripheral tumors, whereas centrally located LADCs were associated with humeral metastases (p = 0.018). Moreover, we deduced that left-sided tumors give rise to skull metastases more often than right-sided primary tumors (p = 0.018). Of note, however, the localization of the primary tumor did not significantly influence the type of affected bones. Multivariate Cox regression analysis adjusted for clinical parameters demonstrated that central localization of the primary tumor was an independent negative prognostic factor for overall survival (OS). Additionally, as expected, both chemotherapy and bisphosphonate therapy conferred a significant benefit for OS. Conclusion: The present study demonstrates unique bone-specific metastasis patterns concerning primary tumor location. Peripherally located LADCs are associated with rib and femoral metastases and improved survival outcomes. Our findings might contribute to the development of individualized follow-up strategies in bone-metastatic LADC patients and warrant further clinical investigations on a larger sample size.

Evidence for improved prognosis of colorectal cancer diagnosed following the detection of iron deficiency anaemia

Iron deficiency anaemia (IDA) is common in colorectal cancer (CRC), especially, in right-sided CRC which is known to have an overall worse prognosis. The associations between diagnostic pathway (Bowel Cancer Screening Programme (BCSP), IDA, symptomatic) and tumour side/stage was assessed using logistic regression models in 1138 CRC cases presenting during 2010-2016 at a single secondary-care centre in the UK. In the IDA sub-group, the relationship between CRC stage and the event of having a blood count prior to CRC diagnosis was examined using Bayesian parametric survival model. IDA was found as the only significant predictor of right-sided CRC (OR 10.61, 95% CI 7.02-16.52). Early-stage CRC was associated with both the IDA (OR 1.65, 95% CI 1.18-2.29) and BCSP pathway (OR 2.42, 95% CI 1.75-3.37). At any age, the risk of detecting CRC at late-stage was higher in those without a previous blood count check (hazard ratio 1.53, 95% credibility interval 1.08-2.14). The findings of this retrospective observational study suggest a benefit from diagnosing CRC through the detection of IDA, and warrant further research into the prognosis benefit of systematic approach to blood count monitoring of the at-risk population.

A clinico-pathological and molecular analysis reveals differences between solitary (early and late-onset) and synchronous rectal cancer

Rectal cancer (RC) appears to behave differently compared with colon cancer. We aimed to analyze existence of different subtypes of RC depending on distinct features (age of onset and the presence of synchronous primary malignant neoplasms). We compared the clinicopathological, familial and molecular features of three different populations diagnosed with RC (early-onset RC [EORC], late-onset RC, and synchronous RC [SRC]). Eighty-five RCs were identified and were evaluated according to their microsatellite instability, CpG Island Methylator Phenotype (CIMP) and chromosomal instability, as assessed by Next Generation Sequencing and microarray-based comparative genomic hybridization approaches. The results were subjected to cluster analysis. SRCs displayed the most specific characteristics including a trend for the development of multiple malignant neoplasms, a greater proportion of CIMP-High tumors (75%) and more frequent genomic alterations. These findings were confirmed by a clustering analysis that stratified RCs according to their genomic alterations. We also found that EORCs exhibited their own features including an important familial cancer component and a remarkable rate of mutations in TP53 (53%). Together, heterogeneity in RC characteristics by age of disease-onset and SRC warrants further study to optimize tailored prevention, detection and intervention strategies-particularly among young adults.

Early-onset colorectal cancer: more than one side to the story

Aim: To determine the impact of tumor sidedness on all-cause mortality for early- (age 18–49 years) and older-onset (age ≥50 years) colorectal cancer (CRC). Materials & methods: We conducted a retrospective study of 650,382 patients diagnosed with CRC between 2000 and 2016. We examined the associations of age, tumor sidedness (right colon, left colon and rectum) and all-cause mortality. Results: For early-onset CRC (n = 66,186), mortality was highest in the youngest age group (18–29 years), driven by left-sided colon cancers (vs 50–59 years, hazard ratio: 1.18; 95% CI: 1.03–1.34). 5-year risk of death among 18–29-year-olds with left-sided colon cancer (0.42, 95% CI: 0.38, 0.46) was higher than all other age groups. Conclusion: Left-sided colon cancers are enriched in younger adults and may be disproportionately fatal.

Difference in survival between right- versus left-sided colorectal neuroendocrine neoplasms

Neuroendocrine neoplasms (NENs) are a heterogeneous group of tumors that arise from neuroendocrine cells, and in some cases are capable of producing agents that may cause characteristic hormonal syndromes (Cives and Strosberg, 2018). Such tumors were previously thought to be rare, but the rate of detection of NENs, especially from the gastrointestinal tract, is increasing with the widespread use of colonoscopy, cross-sectional imaging, and biomarkers (Gu et al., 2019). A study based on the Surveillance, Epidemiology, and End Results (SEER) database showed that the age-adjusted incidence of NENs increased 6.4-fold from 1973 (1.09 per 100 000) to 2012 (6.98 per 100 000) (Dasari et al., 2017), while there was a progressive increase in the incidence of colorectal NENs (Starzyńska et al., 2017).

IS THERE A DIFFERENCE BETWEEN RIGHT- VERSUS LEFT-SIDED COLON CANCERS? DOES SIDE MAKE ANY DIFFERENCE IN LONG-TERM FOLLOW-UP?

BACKGROUND

Since 1990 it was proposed that distal and proximal location of colon cancer might follow different biological, epidemiology, pathology and prognosis, probably due to embryologic different development of the two segments of the colon, which may represent two separate disease entities. These differences might have consequences for the treatment of patients with colorectal cancer.

AIM

To compare the characteristics between patients with right and left colon cancer, with severity and tumor characteristic that influence in the survival of these patients.

METHOD

Were evaluated the outcomes of surgical treatment of patients with colon cancer with data collected retrospectively from prospectively collected database.

RESULTS

The tumor's side did not influence survival time of patients with colon cancer (p=0.112) in the regression model. Only the diseases stage leads to influence on survival time; patients with right colon cancer have more advanced staging (III or IV) and present a risk of death greater in 3.23 times.

CONCLUSION

This analysis provides evidence that the prognosis of localized left-sided colon cancer is better compared to right-sided colon cancer. Also, the patients with right colon cancer have more advanced stage, mucinous tumor and are older.

Clinical and Molecular Comparative Study of Colorectal Cancer Based on Age-of-onset and Tumor Location: Two Main Criteria for Subclassifying Colorectal Cancer

Our aim was to characterize and validate that the location and age of onset of the tumor are both important criteria to classify colorectal cancer (CRC). We analyzed clinical and molecular characteristics of early-onset CRC (EOCRC) and late-onset CRC (LOCRC), and we compared each tumor location between both ages-of-onset. In right-sided colon tumors, early-onset cases showed extensive Lynch syndrome (LS) features, with a relatively low frequency of chromosomal instability (CIN), but a high CpG island methylation phenotype. Nevertheless, late-onset cases showed predominantly sporadic features and microsatellite instability cases due to BRAF mutations. In left colon cancers, the most reliable clinical features were the tendency to develop polyps as well as multiple primary CRC associated with the late-onset subset. Apart from the higher degree of CIN in left-sided early-onset cancers, differential copy number alterations were also observed. Differences among rectal cancers showed that early-onset rectal cancers were diagnosed at later stages, had less association with polyps, and more than half of them were associated with a familial LS component. Stratifying CRC according to both location and age-of-onset criteria is meaningful, not only because it correlates the resulting categories with certain molecular bases, but with the confirmation across larger studies, new therapeutical algorithms could be defined according to this subclassification.

Colon Cancer Sidedness, Presentation, and Survival at Different Stages

Background

Several prognostic factors have been used to guide therapy for colon cancer (CC). However, the relationship between CC laterality (sidedness) and prognosis remains under investigation.

Objectives

To assess the effect of laterality on CC presentation and survival, using a Surveillance, Epidemiology, and End Results (SEER) population-based cohort.

Methods

A retrospective cohort study using data from the SEER program (2007-2015).

Results

Of the 163,980 patients with CC, 85,779 (52.3%) presented with right-sided CC (RCC) and 78,201 (47.7%) with left-sided CC (LCC). Stage distributions were as follows: stage I, 24.1%; stage II, 27.3%; stage III, 28.2%; and stage IV, 20.4%. In an adjusted modified Poisson regression approach for risk ratio (RR), patients with LCCs were more likely to be male (RR = 1.14; 95% CI 1.12-1.15, p<0.001). As compared to stage I, stage II cancers (RR = 0.88, 95% CI 0.87-0.90, p<0.001) were less likely to be LCC. Stage IV CC was slightly less likely to be left-sided (RR = 0.98, 95% CI 0.98, 0.96-1.00, p = 0.028). The median overall survival (OS) for RCC was 87 months. The median OS for LCC was not established, as more than half of the patients diagnosed with LCC were still living at the time of the analysis. In adjusted Cox proportional Hazard model, individuals with stage I, III, and IV LCCs had superior OS as compared to those with matched-stage RCC (adjusted HR = 0.87; 95% CI 0.85-0.88, p<0.001). However, OS was worse among those with stage II disease who presented with LCC (adjusted Hazard ratio [aHR] = 1.06; 95% CI 1.02-1.11, p = 0.004). CC-specific survival (CSS) was superior for LCC versus RCC for stages III and IV but worse for II.

Conclusions

In this population-cohort study, LCC is associated with superior OS and CSS survival. The overall survival advantage was attributed to stage I, III, and IV disease. Individuals presenting with stage II disease exhibit superior survival if the CC is right-sided.

Primary tumor location in stage III colon cancer has prognostic impact on subsequent liver metastasis

BACKGROUND AND OBJECTIVES

We aim to investigate whether a difference exists between right-sided and left-sided colon cancer at the same disease stage and subsequent liver metastasis and identify whether tumor location can independently influence survival.

METHODS

Right-sided colon cancer was defined as malignancy arising from the cecum to the transverse colon; left-sided colon cancer was defined as malignancy arising from the splenic flexure to the sigmoid colon. Clinicopathological features and survival data were collected for analysis.

RESULTS

Overall, 1442 patients were included for analysis. The median follow-up time was 58.2 months. Patients with left-sided colon cancer had better 5-year overall survival (75.2% vs 61.7%, P = 0.005), 5-year cancer-specific survival (81.6% vs 73.4%, P = 0.001), and 5-year recurrence-free survival (70.9% vs 66.5%, P = 0.033) compared with patients having right-sided colon cancer. After the presentation of subsequent liver metastasis, patients with primary left-sided colon cancer had better 3-year cancer-specific survival ( P < 0.001). In the multivariate analysis, cancer location was an independent prognostic factor for cancer-specific survival (right vs left, HR: 1.276, 95% CI: 1.002-1.625).

CONCLUSIONS

The primary tumor location can serve as a prognostic factor for treatment outcomes either in primary stage III colon cancer or subsequent liver metastasis.

Different Anatomical Subsites of Colon Cancer and Mortality: A Population-Based Study

Background

In terms of incidence and pathogenesis, right-sided colon cancer (RCC) and left-sided colon cancer (LCC) exhibit several differences. However, whether existing differences could reflect the different survival outcomes remains unclear. Therefore, we aimed to ascertain the role of location in the prognosis.

Methods

We identified colon cancer cases from the Surveillance, Epidemiology, and End Results database between 1973 and 2012. Differences among subsites of colon cancer regarding clinical features and metastatic patterns were compared. The Kaplan-Meier curves were conducted to compare overall and disease-specific survival in relation to cancer location. The effect of tumour location on overall and cancer-specific survival was analysed by Cox proportional hazards model.

Results

A total of 377,849 patients from SEER database were included in the current study, with 180,889 (47.9%) RCC and 196,960 (52.1%) LCC. LCC was more likely to metastasize to the liver and lung. Kaplan-Meier curves demonstrated that LCC patients had better overall and cancer-specific survival outcomes. Among Cox multivariate analyses, LCC was associated with a slightly reduced risk of overall survival (HR, 0.92; 95% CI, 0.92-0.93) and cancer-specific survival (HR, 0.92; 95% CI, 0.91-0.93), even after adjusted for other variables. However, the relationship between location and prognosis was varied by subgroups defined by age, year at diagnosis, stage, and therapies.

Conclusions

We demonstrated that LCC was associated with better prognosis, especially for patients with distant metastasis. Future trails should seek to identify the underlying mechanism.

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.

Additional lymphadenectomy might not improve survival of patients with resectable metastatic colorectal adenocarcinoma of T4 stage, proximal location, poor/undifferentiation, or N3/N4 stages: a large population-based study

This study was performed to evaluate the prognostic effect of lymphadenectomy on outcomes in patients with resectable metastatic colorectal adenocarcinoma (mCRC). We selected patients with mCRC from 2004 to 2013 from Surveillance, Epidemiology, and End Results Program (SEER) database. Kaplan-Meier analysis, univariate Cox regression and multivariate Cox regression analysis were performed to assess the clinical value of lymphadenectomy on overall survival (OS) and cause-specific survival (CSS) of patients with resectable mCRC. A total 24178 eligible patients were included, 23056 (95.36%) of which received lymphadenectomy. Results showed that lymphadenectomy was an independent protective factor for survival of patients with mCRC overall [OS (HR: 0.86, 95%CI: 0.79-0.93, P=0.002) and CSS (HR: 0.85, 95%CI: 0.78-0.93, P<0.001)]. Further analysis showed that lymphadenectomy improved survival of patients with T1 stage [OS (HR: 0.51, 95%CI: 0.39-0.66, P<0.001); CSS (HR: 0.48, 95%CI: 0.36-0.65, P<0.001)], distal [OS (HR: 0.65, 95%CI: 0.56-0.75, P<0.001); CSS (HR: 0.65, 95%CI: 0.65-0.75, P<0.001)], rectal [OS (HR: 0.60, 95%CI: 0.52-0.70, P<0.001); CSS (HR: 0.59, 95%CI: 0.51-0.69, P<0.001)] , well/moderately differentiated [OS (HR: 0.62, 95%CI: 0.56-0.70, P<0.001); CSS (HR: 0.62, 95%CI: 0.55-0.69, P<0.001)], N1 stage [OS (HR: 0.76, 95%CI: 0.67-0.85, P<0.001); CSS (HR: 0.74, 95%CI: 0.65-0.84, P<0.001)] and N2 stage [OS (HR: 0.63, 95%CI: 0.54-0.74, P<0.001; CSS (HR: 0.65, 95%CI: 0.55-0.77, P<0.001)) mCRC. While lymphadenectomy might not improve survival of patients with T4 stage, proximal, poor or undifferentiated, N3 and N4 stage mCRC. In general, Additional lymphadenectomy was suggested for patients with mCRC overall. However, lymphadenectomy might not improve survival of patients with mCRC of higher malignancy tendency, such as T4 stage, proximal location, poor or undifferentiation, N3 and N4 stages.

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.

The Confluence of Sex Hormones and Aging on Immunity

The immune systems of post-pubescent males and females differ significantly with profound consequences to health and disease. In many cases, sex-specific differences in the immune responses of young adults are also apparent in aged men and women. Moreover, as in young adults, aged women develop several late-adult onset autoimmune conditions more frequently than do men, while aged men continue to develop many cancers to a greater extent than aged women. However, sex differences in the immune systems of aged individuals have not been extensively investigated and data addressing the effectiveness of vaccinations and immunotherapies in aged men and women are scarce. In this review, we evaluate age- and sex hormone-related changes to innate and adaptive immunity, with consideration about how this impacts age- and sex-associated changes in the incidence and pathogenesis of autoimmunity and cancer as well as the efficacy of vaccination and cancer immunotherapy. We conclude that future preclinical and clinical studies should consider age and sex to better understand the ways in which these characteristics intersect with immune function and the resulting consequences for autoimmunity, cancer, and therapeutic interventions.

Clinical significance of circulating immune cells in left- and right-sided colon cancer

Background

Left-sided and right-sided colon cancers (LCCs and RCCs, respectively) differ in their epidemiology, pathogenesis, genetic and epigenetic alterations, molecular pathways and prognosis. Notably, immune response gene expression profiles have been shown to differ between patients with LCC and patients with RCC. The immune system plays an important role in tumor immunosurveillance, and there is increasing evidence that peripheral blood immune cells have a profound influence on tumor prognosis. This study aimed to determine the clinical significance of circulating immune cells with respect to colon tumor locations.

Methods

Different types of circulating immune cells were separated and analysed based on their surface markers by flow cytometry. We compared the numbers of dendritic cells (DCs) and T cell subsets in the peripheral blood of 94 patients with RCC or LCC and analysed the proportions of these immune cells in relation to tumor stage, tumor differentiation and lymphatic metastasis.

Results

We show that at later tumor stages, patients with LCC had higher levels of circulating myeloid DCs (P = 0.049) and plasmacytoid DCs (P = 0.018) than patients with RCC. In poorly differentiated tumors, LCC patients had significantly higher amount of plasmacytoid DCs (P = 0.036), CD4⁺ memory T (Tm) cells (P = 0.012), CD4⁺ T cells (P = 0.028), Tm cells (P = 0.014), and regulatory T cells (P = 0.001) than RCC patients. The levels of circulating CD4⁺ T cells, Tm cells and CD4⁺ Tm cells were significantly elevated at later stages in patients with LCC or RCC, while these cells decreased in poorly differentiated tumors in patients with RCC. Moreover, CD4⁺ Tm cell and CD4⁺ T cell levels are significantly associated with lymph node metastasis in patients with LCC and RCC.

Discussion

Circulating immune cells were associated with tumor location, tumor stage and tumor differentiation, and can be used to predict lymphatic metastasis in patients with colon cancer. This variation in systemic immunity could contribute to the differential prognosis of patients with colon cancer.

Differences in Cancer-Specific Mortality of Right- Versus Left-Sided Colon Adenocarcinoma: A Surveillance, Epidemiology, and End Results Database Analysis

Purpose

Studies have shown an increased risk for all-cause mortality with right-sided colon cancer (RCC) as compared with left-sided colon cancer (LCC). However, these studies were unable to directly account for mortality events unrelated to cancer, known as other-cause mortality. We investigated the difference in cancer-specific mortality (CSM) between RCC and LCC at localized, regional, and metastatic stages, according to the Fine and Gray proportional hazards model, while accounting for other-cause mortality as a competing risk.

Methods

Using the SEER database, we identified 90,635 patients with LCC (ie, involving the splenic flexure, descending, sigmoid, and rectosigmoid colon) and 112,679 patients with RCC (ie, involving the cecum, ascending, hepatic flexure, and transverse colon) diagnosed from 1998 to 2013. We performed a competing risk analysis for CSM using the Fine and Gray proportional hazard model, adjusting for age, sex, race, tumor grade, surgery status, year of diagnosis, and tumor laterality, with two-sided testing and a statistical significance threshold of 0.05.

Results

Compared with LCC, RCC demonstrated statistically significant decreased CSM at the localized stage (adjusted hazards ratio [AHR], 0.865; P < .001), equivalent CSM at the regional stage (AHR, 0.990; P = .440), and increased CSM at the metastatic stage (AHR, 1.175; P < .001).

Conclusion

Using a competing risk model, we have shown that RCC, compared with LCC, is associated with lower CSM at the localized stage, equivalent CSM at the regional stage, and higher CSM at the metastatic stage. This pattern may correlate with variation in genetic factors, including known decreased prevalence of microsatellite instability in RCC with regional and metastatic disease.

Is whole-colon investigation by colonoscopy, computerised tomography colonography or barium enema necessary for all patients with colorectal cancer symptoms, and for which patients would flexible sigmoidoscopy suffice? A retrospective cohort study

BACKGROUND

For patients referred to hospital with suspected colorectal cancer (CRC), it is current standard clinical practice to conduct an examination of the whole colon and rectum. However, studies have shown that an examination of the distal colorectum using flexible sigmoidoscopy (FS) can be a safe and clinically effective investigation for some patients. These findings require validation in a multicentre study.

OBJECTIVES

To investigate the links between patient symptoms at presentation and CRC risk by subsite, and to provide evidence of whether or not FS is an effective alternative to whole-colon investigation (WCI) in patients whose symptoms do not suggest proximal or obstructive disease.

DESIGN

A multicentre retrospective study using data collected prospectively from two randomised controlled trials. Additional data were collected from trial diagnostic procedure reports and hospital records. CRC diagnoses within 3 years of referral were sourced from hospital records and national cancer registries via the Health and Social Care Information Centre.

SETTING

Participants were recruited to the two randomised controlled trials from 21 NHS hospitals in England between 2004 and 2007.

PARTICIPANTS

Men and women aged ≥ 55 years referred to secondary care for the investigation of symptoms suggestive of CRC.

MAIN OUTCOME MEASURE

Diagnostic yield of CRC at distal (to the splenic flexure) and proximal subsites by symptoms/clinical signs at presentation.

RESULTS

The data set for analysis comprised 7380 patients, of whom 59% were women (median age 69 years, interquartile range 62-76 years). Change in bowel habit (CIBH) was the most frequently presenting symptom (73%), followed by rectal bleeding (38%) and abdominal pain (29%); 26% of patients had anaemia. CRC was diagnosed in 551 patients (7.5%): 424 (77%) patients with distal CRC, 122 (22%) patients with cancer proximal to the descending colon and five patients with both proximal and distal CRC. Proximal cancer was diagnosed in 96 out of 2021 (4.8%) patients with anaemia and/or an abdominal mass. The yield of proximal cancer in patients without anaemia or an abdominal mass who presented with rectal bleeding with or without a CIBH or with a CIBH to looser and/or more frequent stools as a single symptom was low (0.5%). These low-risk groups for proximal cancer accounted for 41% (3032/7380) of the cohort; only three proximal cancers were diagnosed in 814 low-risk patients examined by FS (diagnostic yield 0.4%).

LIMITATIONS

A limitation to this study is that changes to practice since the trial ended, such as new referral guidelines and improvements in endoscopy quality, potentially weaken the generalisability of our findings.

CONCLUSIONS

Symptom profiles can be used to determine whether or not WCI is necessary. Most proximal cancers were diagnosed in patients who presented with anaemia and/or an abdominal mass. In patients without anaemia or an abdominal mass, proximal cancer diagnoses were rare in those with rectal bleeding with or without a CIBH or with a CIBH to looser and/or more frequent stools as a single symptom. FS alone should be a safe and clinically effective investigation in these patients. A cost-effectiveness analysis of symptom-based tailoring of diagnostic investigations for CRC is recommended.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN95152621.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 66. See the NIHR Journals Library website for further project information.

Relationship between drugs affecting the renin-angiotensin system and colorectal cancer: The MCC-Spain study

The potential protective effect of renin-angiotensin system (RAS) inhibitors is a subject of increasing interest due to their possible role as chemopreventive agents against colorectal cancer (CRC). To evaluate this association, we conducted a case-control study with 2165 cases of colorectal cancer, diagnosed between 2007 and 2012, and 3912 population controls frequency matched (by age, sex and region) from the Spanish multicenter case-control study MCC-Spain. We found a significant protective effect of the angiotensin-converting enzyme Inhibitors (ACEIs) against CRC, limited to the under-65years group (OR=0.65 95%CI (0.48-0.89)) and to a lesser degree to men (OR=0.81 95%CI (0.66-0.99). In contrast, the angiotensin receptor blockers (ARBs) did not show a significant effect. Regarding the duration of use, a greater protection was observed in men as the length of consumption increases. In contrast, in the under-65 stratum, the strongest association was found in short-term treatments. Finally, by analyzing ACEIs effect by colon subsite, we found no differences, except for under 65years old, where the maximum protection was seen in the proximal intestine, descending in the distal and rectum (without statistical significance). In conclusion, our study shows a protective effect on CRC of the ACEis limited to males and people under 65years old, which increases in proximal colon in the latter. If confirmed, these results may suggest a novel approach to proximal CRC prevention, given the shortcomings of colonoscopy screening in this location.

Influence of primary site on metastatic distribution and survival in stage IV colorectal cancer

BACKGROUND

To assess pattern distribution and prognosis of the three anatomical entities of metastatic colorectal cancer, and influence of treatment of metastases on survival.

METHODS

Patients presenting with stage IV colorectal cancer (synchronous group), or who developed metastatic recurrence (metachronous group) after initial curative treatment between January 2005 and August 2015 were reviewed. Right sided (cecum to transverse colon), left sided (splenic flexure to sigmoid colon) and rectal cancers were identified. Distribution of metastases were noted as hepatic, lung or peritoneal.

RESULTS

Of 374 patients, 276 were synchronous, 98 were metachronous. Metachronous group had a better 3-year survival (54%, 95% CI: 42-64 versus 33%, 95% CI: 27-39, log rank P = 0.0038). There were equal numbers of right (n = 119), left (n = 115) and rectal cancers (n = 140). Rectal cancers had a higher metastatic recurrence, yet demonstrated better 3-year survival (right colon 45%, 95% CI: 19-67, left colon 49%, 95% CI: 27-68, rectum 59%, 95% CI: 42-72, P = 0.39) due to higher proportions of metachronous patients undergoing treatment for metastases (40 versus 14%). Over half of all organ metastases spread to liver, with equal distribution from all three anatomical groups. Rectal cancers showed highest preponderance for lung metastases.

CONCLUSION

Rectal cancers have a higher chance of recurring, with a higher metastatic rate to the lung, yet demonstrate better survival outcomes in metastatic colorectal cancer, reflecting the benefit of intervention for metastases.

The impact of BMI on early colorectal neoplastic lesions and the role of endoscopic diagnosis:. An Italian observational study

INTRODUCTION

CRC often arises from polyps: an early detection and resection are effective in decreasing both incidence and mortality rate. Relation between risk factors, adenomas and CRC have been showed, but there is little evidence for overweight association with preneoplastic lesions. This study analyzed the correlation between body mass index (BMI) and primitive site of polyps.

METHODS

We performed a retrospective study, in a period between January 2010 and October 2014. Subjects aged 50 years and older who underwent their first-time screening colonoscopy were included. Reports regarding characteristic of the polyps were collected.

RESULTS

142 patients were enrolled and they were divided into two groups: group I - patients with left sided colonic polyps, and group II - patients who right sided colonic polyps. The ANOVA test-one way, documents a difference between the BMI and the colon localization of polyps.

CONCLUSIONS

Patients with overweight had a higher risk to develop lesions in the left colon compared to patients with normal weight. Despite the fact that Italian epidemiological studies have found a prevalence of polyps of 44-53% in rectal-sigmoid segment, 32-36% in transverse segment and of 14-20% in right segment, we showed an incidence of 26.05% for right sided polyps, which maybe related with the eating habits of the territory.

Symptomatic Versus Asymptomatic Colorectal Cancer: Predictive Features at CT Colonography

RATIONALE AND OBJECTIVES

Computed tomographic colonography (CTC) is a robust tool for evaluating colorectal lesions in both screening and diagnostic settings. The purpose of this study was to assess the relationship between colorectal cancer (CRC) tumor characteristics and patient symptomatology.

MATERIALS AND METHODS

This is a retrospective analysis of all pathology-confirmed cases of CRC evaluated with CTC at our institution from October 2004 to October 2012. Cases were reviewed to determine tumor size, morphology, and degree of luminal narrowing. An electronic medical record review was performed to delineate specific patient symptomatology and determine depth of invasion.

RESULTS

A total of 55 patients (36 symptomatic and 19 asymptomatic) with a total of 63 CRCs were evaluated by CTC during the study time period. The most common symptoms were gastrointestinal (GI) bleeding/anemia (n = 26), followed by obstructive symptoms (n = 23), and constitutional symptoms (n = 5). Symptomatic cancers were more likely to have annular morphology (n = 30/43, 70% vs. n = 3/20, 15%; odds ratio [OR] = 13.1, P = 0.0003), whereas asymptomatic cancers were more likely to be polypoid (n = 11/20, 55% vs. n = 6/43, 14%, OR = 7.5, P = 0.001). Symptomatic cancers were also larger (46.1 ± 22.4 vs. 38.8 ± 18.4 mm, P = 0.005) and resulted in greater luminal narrowing (8.7 ± 8.5 mm vs. 35.8 ± 18.8 mm, P < 0.0001) with deeper invasion (n = 29/35 [invasion unknown for 8 cases], 83% vs. n = 6/20, 30%, OR = 11.3, P = 0.0003). Invasive cancers were more likely to have annular morphology (66%, 23/25, P = 0.002).

CONCLUSIONS

There is an intuitive and predictable relationship between tumor characteristics on CTC and patient symptoms. Annular morphology, tumor size, degree of luminal narrowing, and invasive disease all correlate with the presence of symptoms.

Clinicopathologic Features and Outcome of Young Adults With Stage IV Colorectal Cancer

PURPOSE

Colorectal cancer has a distinct clinicopathologic presentation in younger patients. The aim of this paper was to evaluate the outcome of younger (age below 50 y) and older patients with stage IV (advanced) colorectal cancer in the modern era of combination chemotherapy.

METHODS

Cases of metastatic colorectal cancer reported in Surveillance, Epidemiology, and End Results registry (1973 to 2008) were reviewed. Demographics, tumor characteristics, and overall and cancer-specific survivals in patients below 50 and above 50 years of age were compared by Cox proportional hazard analyses. Joinpoint regression analysis was used to evaluate secular trends in 2-year survival.

RESULTS

Younger patients had a greater proportion of negative clinicopathologic features (male sex, African American ethnicity, and signet ring or mucinous histology). In multivariate analysis, older age, male sex, African American ethnicity, right-sided tumors, and signet ring histology were associated with higher mortality risk. Younger patients had improved survival (hazard ratio 0.72; 95% confidence interval: 0.70-0.75) compared with older patients, whereas all patients experienced increased 2-year survival by joinpoint analysis beginning in 1999-2000.

CONCLUSIONS

The results confirm decreased mortality from advanced colorectal cancer in the era of modern combination chemotherapy in younger and older patients. Younger age, non-right-sided tumors, and absence of signet ring histology significantly associate with better survival.

Accuracy of preoperative T and N staging in colon cancer--a national population-based study

AIM

To select patients for neoadjuvant therapy in colon cancer, there is a need to improve pre-therapeutic locoregional staging. There are now data showing that the TN stage can be adequately assessed by preoperative CT in dedicated centres. In Sweden the use of preoperative CT of the abdomen for staging of the primary tumour is increasing. The aim of this study was to determine to what extent the preoperatively reported radiological TN stage correlates with the histopathological TN stage in an entire population.

METHOD

Data were collected on the preoperative cTN stage according to the radiologist and postoperative pTN stage according to the pathologist on all patients operated on for colon cancer in Sweden 2007-2010. The correlation between cTN stage and pTN stage was calculated using kappa statistics.

RESULTS

T stage was compared in 4373 patients with cT and pT stage. The correlation coefficient was 0.44, indicating fair agreement. The cN and pN correlation coefficient was 0.28, indicating a slight correlation. There was no difference in correlation related to age, gender, tumour location, body mass index or emergent vs elective surgery. A slight difference was seen between different geographical regions.

CONCLUSION

Preoperative CT in an unselected population does not result in an accurate cTN staging as previously reported from dedicated centres. To achieve adequate preoperative cTN staging nationally, the education of radiologists and optimization of the radiological method will be necessary.

Location of colon cancer (right-sided versus left-sided) as a prognostic factor and a predictor of benefit from cetuximab in NCIC CO.17

BACKGROUND

Right- and left-sided colon cancers (RC, LC) differ with respect to biology, pathology and epidemiology. Previous data suggest a mortality difference between RC and LC. We examined if primary tumour side also predicts for outcome in chemotherapy refractory, metastatic colon cancer (MCC). We also compared RC versus LC as a predictor of efficacy of epidermal growth factor receptor (EGFR) inhibition with cetuximab.

METHODS

Reanalyzing NCIC CO.17 trial (cetuximab versus best supportive care [BSC]), we coded the primary tumour side as RC (caecum to transverse colon) or LC (splenic flexure to rectosigmoid). The association between tumour side and baseline characteristics was assessed. Cox regression models determined factors affecting overall survival (OS) and progression free survival (PFS).

RESULTS

Patients with RC (150/399) had more poorly differentiated, mutant KRAS, mutated PIK3CA and wild-type BRAF tumours, fewer liver and lung metastases, and shorter interval between diagnosis and study entry. Among BSC patients, tumour side was not prognostic for PFS (hazard ratios (HR) 1.07 [0.79-1.44], p = 0.67) or OS (HR 0.96 [0.70-1.31], p = 0.78). Among wild-type KRAS patients, those with LC had significantly improved PFS when treated with cetuximab compared to BSC (median 5.4 versus 1.8 months, HR 0.28 [0.18-0.45], p < 0.0001), whereas those with RC did not (median 1.9 versus 1.9 months, HR 0.73 [0.42-1.27], p = 0.26), [interaction p = 0.002].

CONCLUSION

In refractory MCC, tumour location within the colon is not prognostic, but is strongly predictive of PFS benefit from cetuximab therapy. Additional research is needed to understand the molecular differences between RC and LC and their interaction with EGFR inhibition.

Tumor suppressors miR-143 and miR-145 and predicted target proteins API5, ERK5, K-RAS, and IRS-1 are differentially expressed in proximal and distal colon

The colon differs regionally in local luminal environment, excretory function, and gene expression. Polycistronic microRNA (miR)-143 and miR-145 are downregulated early in colon cancer. We asked if these microRNAs (miRNAs) might be differentially expressed in the proximal vs. the distal colon, contributing to regional differences in protein expression. Primary transcripts and mature miR-143 and miR-145 were quantified by real-time PCR, putative targets were measured by Western blotting, and DNA methylation was assessed by sequencing bisulfite-treated DNA in proximal and distal normal colonic mucosa as well as colon cancers. Putative targets of these miRNAs were assessed following transfection with miR-143 or miR-145. Mean expression of mature miR-143 and miR-145 was 2.0-fold (P < 0.001) and 1.8-fold (P = 0.03) higher, respectively, in proximal than distal colon. DNA methylation or primary transcript expression of these miRNAs did not differ by location. In agreement with increased expression of miR-143 and miR-145 in proximal colon, predicted targets of these miRNAs, apoptosis inhibitor 5 (API5), ERK5, K-RAS, and insulin receptor substrate 1 (IRS-1), which are cell cycle and survival regulators, were expressed at a lower level in proximal than distal colon. Transfection of HCA-7 colon cancer cells with miR-145 downregulated IRS-1, and transfection of HT-29 colon cancer cells with miR-143 decreased K-RAS and ERK5 expression. In conclusion, miR-143 and miR-145 and the predicted target proteins API5, ERK5, K-RAS, and IRS-1 display regional differences in expression in the colon. We speculate that differences in these tumor suppressors might contribute to regional differences in normal colonic gene expression and modulate site-specific differences in malignant predisposition.

Early-onset colorectal cancer: a separate subset of colorectal cancer

Colorectal cancer (CRC) has a great impact on the world population. With increasing frequency, CRC is described according to the presenting phenotype, based on its molecular characteristics. Classification of CRC tumors according to their genetic and/or epigenetic alterations is not only important for establishing the molecular bases of the disease, but also for predicting patient outcomes and developing more individualized treatments. Early-onset CRC is a heterogeneous disease, with a strong familial component, although the disease is sporadic in an important proportion of cases. Different molecular alterations appear to contribute to the apparent heterogeneity of the early-onset population and subgroups can be distinguished with distinct histopathologic and familial characteristics. Moreover, compared with late-onset CRC, there are characteristics that suggest that early-onset CRC may have a different molecular basis. The purpose of this review was to analyze the current state of knowledge about early-onset CRC with respect to clinicopathologic, familial and molecular features. Together, these features make it increasingly clear that this subset of CRC may be a separate disease, although it has much in common with late-onset CRC.

Is right-sided colon cancer different to left-sided colorectal cancer? - a systematic review

Colorectal cancer (CRC) exhibits differences in incidence, pathogenesis, molecular pathways and outcome depending on the location of the tumor. This review focuses on the latest developments in epidemiological and scientific studies, which have enhanced our understanding on the underlying genetic and immunological differences between the proximal (right-sided) colon and the distal (left-sided) colorectum. The different ways in which environmental risk factors influence the pathogenesis of CRC depending on its location and the variations in surgical and oncological outcomes are also discussed in this review. In the current era of personalized medicine, we aim to reiterate the importance of tumor location in management of CRC and the implication on future clinical and scientific research.

Bleeding-related symptoms in colorectal cancer: a 4-year nationwide population-based study

BACKGROUND

Little is known about the major presenting features of patients with colorectal cancer (CRC) in a population-based setting, especially regarding bleeding-related symptoms.

AIM

To determine the proportion of CRC patients presenting with bleeding-related symptoms, to compare bleeders and nonbleeders and to explore the role of anticoagulants in bleeders.

METHODS

This was a nationwide, population-based, retrospective study, investigating all patients diagnosed with CRC in Iceland from 2008 to 2011. Bleeding-related symptoms were defined as overt bleeding, iron deficiency anaemia or a positive faecal occult blood test. Obstructive symptoms were defined as a confirmed diagnosis of ileus or dilated intestines on imaging.

RESULTS

Data were available for 472/496 (95%) patients, males 51%, mean age 69 (±13) years. In all, 348 (74%) patients had bleeding-related symptoms; of these 348 patients, 61% had overt bleeding. Bleeders were less likely than nonbleeders to have metastases at diagnosis, 19% vs. 34% (P < 0.001). Overt bleeders were less likely than nonbleeders to have obstructive symptoms, 2% vs. 16% respectively (P < 0.0001). Occult bleeders were more likely to have proximal cancer (69%) than both overt (17%) and nonbleeders (44%) (P < 0.0001); however, they were less likely than nonbleeders to have metastases (22% vs. 35%, P < 0.05). Bleeders were more likely to use warfarin than nonbleeders (9% vs. 3%, P < 0.05); the use of low-dose aspirin was the same (24%).

CONCLUSIONS

The majority of patients with CRC present with bleeding-related symptoms. Bleeders with CRC present earlier than nonbleeders. Warfarin use may induce bleeding in some patients, resulting in an earlier diagnosis.

Pretreatment staging of colon cancer in the Swedish population

AIM

Preoperative staging of colon cancer according to Swedish national guidelines implies imaging evaluation of the primary tumour, liver and lungs. Failure to adhere to these guidelines results in negative scorings in the national registration system. In the present study we report the extent of compliance with these guidelines.

METHOD

Since 2007 clinical data on all patients diagnosed with colon cancer in Sweden have been collected in a national database. This includes information on pretherapeutic diagnostic imaging performed, pretherapeutic TNM stage and data on treatment and follow-up. All patients diagnosed with colon cancer in Sweden between 2007 and 2010 were included.

RESULTS

Nine thousand and eight-three patients (i.e. 60.5% of all patients) had a complete pretherapeutic radiological evaluation; 65.2% had a CT or MRI of the primary tumour, whereas over 80% had examinations of the liver and lungs. There were no difference related to sex, but more patients under 75 years had a complete evaluation. There were large differences between different regions; one region performed a complete evaluation of 78.3% of all patients. The proportion of patients examined increased from 53.9 to 65.0% during the study period. Elective cases were more frequently evaluated before treatment than those with an emergency presentation.

CONCLUSION

Most patients in Sweden had a complete pretreatment imaging evaluation of the colon cancer with geographical and time-dependent variations. Knowledge of the importance of these variations and correlation of pre- and postoperative TNM stage is warranted, and such studies are ongoing.

The diversity between pancreatic head and body/tail cancers: clinical parameters and in vitro models

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) can be divided into head, body and tail cancers according to the anatomy. Distinctions in tissue composition, vascularization and innervations have been clearly identified between the head and body/tail of the pancreas both in embryological development and in histopathology. To understand the postulated genotype difference, we present comprehensive information on two PDAC cell lines as typical representatives originating from pancreatic head and body/tail cancers, respectively.

DATA SOURCE

In the present review, we compare the difference between pancreatic head and body/tail cancers regarding clinical parameters and introducing an in vitro model.

RESULTS

Increasing evidence has shown that tumors at different locations (head vs body/tail) display different clinical presentation (e.g. incidence, symptom), treatment efficiency (e.g. surgery, chemotherapy) and thus patient prognosis. However, the genetic or molecular diversity (e.g. mutations, microRNA) between the two subtypes of PDAC has not been elucidated so far. They present different chemo- and/or radio-resistance, extracellular matrix adhesion and invasiveness, as well as genetic profiles.

CONCLUSION

Genetic and tumor biological diversity exists in PDAC according to the tumor localization.

The relationship between proximal and distal colonic adenomas: is screening sigmoidoscopy enough in the presence of a changing epidemiology?

BACKGROUND AND STUDY AIMS

Because the relationship between distal and proximal colonic findings remains uncertain, controversy exists over whether proctosigmoidoscopy or colonoscopy is more suitable for colorectal cancer (CRC) screening. We aim to describe the distribution and characteristics of polyps removed in colonoscopy screening.

PATIENTS AND METHODS

A prospective registry of a colonoscopy-based CRC screening program was developed on asymptomatic individuals over 50 years. All polyps were removed and characterized. Polyp size and histology were noted. Adenomas were considered advanced if they measured greater than 10 mm or were tubulovillous, villous, or malignant. The prevalence of advanced proximal polyps was determined and patients were categorized according to their family history of CRC.

RESULTS

A total of 696 individuals (418 women), aged 57.7 ± 10.3 years, were examined; 45.8% presented a colonic lesion, being adenomatous polyps in 32.7% individuals. Among these, 24.7% were advanced adenomas. Three patients (0.6%) presented invasive CRC. There were no significant differences with respect to sex and family history of CRC between patients with or without adenomas. Adenomas were more prevalent in individuals aged at least 65, irrespective of location (P<0.001). In 65.1% of individuals with adenomatous polyps in the right colon, there were no synchronous adenomas in the left colon (P<0.001). More adenomas were also present in the right colon of patients with no family history of CRC (P<0.001).

CONCLUSION

Most patients with adenomatous polyps in the right colon showed no synchronic adenomas on the left side. Lesions on the right side would have gone undetected if the individuals undergoing CRC screening had been explored with proctosigmoidoscopy.

Colon cancer: association of histopathological parameters and patients' survival with clinical presentation

Available data correlating symptoms of colon cancer patients with the severity of the disease are very limited. In a population-based setting, we correlated information on symptoms of colon cancer patients with several pathological tumor parameters and survival. Information on all patients diagnosed with colon cancer in Iceland in 1995-2004 for this retrospective, population-based study was obtained from the Icelandic Cancer Registry. Information on symptoms of patients and blood hemoglobin was collected from patients' files. Pathological parameters were obtained from a previously performed standardized tumor review. A total of 768 patients entered this study; the median age was 73 years. Tumors in patients presenting at diagnosis with visible blood in stools were significantly more likely to be of lower grade, having pushing border, conspicuous peritumoral lymphocytic infiltration, and lower frequency of vessel invasion. Patients with abdominal pain and anemia were significantly more likely to have vessel invasion. Logistic regression showed that visible blood in stools was significantly associated with protecting pathological factors (OR range 0.38-0.83, p < 0.05). Tumors in patients presenting with abdominal pain were strongly associated with infiltrative margin and scarce peritumoral lymphocytic infiltration (OR = 1.95; 2.18 respectively, p < 0.05). Changes in bowel habits were strongly associated with vessel invasion (OR = 2.03, p < 0.05). Cox regression showed that blood in stools predicted survival (HR = 0.54). In conclusion, visible blood in stools correlates significantly with all the beneficial pathological parameters analyzed and with better survival of patients. Anemia, general symptoms, changes in bowel habits, acute symptoms, and abdominal pain correlate with more aggressive tumor characteristics and adverse outcome for patients.

Trends in colorectal incidence by anatomic subsite from 1985 to 2005: a population-based study

BACKGROUND

Conflicting results on the shift of right-left ratio in colon cancer incidence have been reported. We examine incidence trends by subsite in a population-based study.

MATERIALS AND METHODS

Colorectal cancer cases diagnosed in the 1985-2005 period were identified through the Tuscany Cancer Registry. Colon subsite was defined as proximal and distal; gender, age at diagnosis, histology, and stage were analyzed. Average annual incidence and age-specific rates according to subsite were calculated.

RESULTS

A total of 21,160 colorectal cancer cases were extracted; in 18,311 cases, the subsite was identified: 6,916 rectal, 5,239 proximal, and 6,156 distal. A larger proportion of distal colon cancers presented as early stage when compared with proximal. Incidence of rectal and distal colon cancer remained stable, while proximal colon cancer incidence increased.

CONCLUSIONS

Proximal colon cancer incidence rate increased through the period. Temporal variations in the incidence rate by subsite could suggest different carcinogenic pathways of right- and left-sided colon cancer.

Elderly patients with colon cancer have unique tumor characteristics and poor survival

BACKGROUND

The incidence of colon cancer increases with age, and colon cancer predominantly affects individuals >65 years old. However, there are limited data regarding clinical and pathologic factors, treatment characteristics, and survival of older patients with colon cancer. The objective of this study was to determine the effects of increasing age on colon cancer.

METHODS

Patients diagnosed with colon cancer between 1988 and 2006 were identified through the Los Angeles County Cancer Surveillance Program, in Southern California. Patients were stratified into 4 age groups: 18-49, 50-64, 65-79, and ≥80 years. Clinical and pathologic characteristics and disease-specific and overall survival were compared between patients from different age groups.

RESULTS

A total of 32,819 patients were assessed. Patients aged 18 to 49 and 65 to 79 years represented the smallest and largest groups, respectively. A near equal number of males and females were diagnosed with colon cancer in the 3 youngest age groups, whereas patients who were ≥80 years old were more commonly white and female. Tumor location was different between groups, and the frequency of larger tumors (>5 cm) was greatest in youngest patients (18-49 years). The oldest patients (≥80 years) were administered chemotherapy at the lowest frequency, and disease-specific and overall survival rates decreased with increasing age.

CONCLUSIONS

This investigation demonstrates that older age is associated with alterations in clinical and pathologic characteristics and decreased survival. This suggests that the phenotype of colon cancer and the efficacy of colon cancer therapies may be dependent on the age of patients.

Temporal trends in incidence and mortality rates for colorectal cancer by tumor location: 1975-2007

OBJECTIVES

We evaluated changes in colorectal cancer (CRC) incidence and mortality by anatomic site to assess the possible impact of CRC screening.

METHODS

Using data from 9 Surveillance, Epidemiology, and End Results cancer registries, we estimated trends in 1975-2007 CRC incidence and 1985-2007 incidence-based mortality. We evaluated trends separately for proximal and distal CRC, overall and by stage, tumor site, and race.

RESULTS

Between 1975 and 2007, 323 237 adults in the study area were diagnosed with CRC. For most tumor and population subgroups, incidence rates increased between 1975 and 1985 and subsequently declined markedly. Declines were most rapid between 1999 and 2007 and were greater for distal than proximal CRC. Declines in incidence were greater for White than Black adults and greatest for regional-stage disease. There was little difference in trends across subsites within the proximal and distal colorectum. Declines in incidence-based mortality mirrored those for incidence.

CONCLUSIONS

Recent declines in CRC incidence and mortality are greater for distal than proximal CRC. Differing trends across populations may reflect variations in screening prevalence; distinct trends by tumor characteristics likely reflect differences in screening efficacy.

Association of symptoms of colon cancer patients with tumor location and TNM tumor stage

OBJECTIVE

Colon cancer is the second most common cause of cancer death in Iceland and accounts for 8% of malignancies. We related information on symptoms of colon cancer patients with information on tumor location and pTNM-stage.

MATERIAL AND METHODS

The study is retrospective and population-based. Information on all patients diagnosed with colon cancer in Iceland in 1995-2004 was obtained. Information on symptoms of patients and blood hemoglobin was collected from patients' files. The pathological parameters were derived from a previously performed study.

RESULTS

A total of 768 patients (422 males, 346 females) participated in this study. Median age was 73 years. Nearly 60% had anemia at the time of diagnosis, 53% had visible blood in stools, and 65% had changes in bowel habits. Around 84% had visible blood in stools and/or anemia. Of those with right-sided tumors, 75% had anemia and were more likely to be diagnosed incidentally (40%) than those with left-sided tumors (20%). Left-sided tumors were associated with blood in stools (68% compared to 41%, p < 0.05) and changes in bowel habits (74% compared to 57%, p < 0.05). Multivariate analysis indicated that blood in stools was strongly associated with a lower TNM-stage (OR = 0.75, p < 0.05). Anemia was strongly associated with a higher TNM-stage (OR = 1.84, p < 0.05).

CONCLUSION

Right-sided tumors were associated with anemia and incidental diagnosis; left-sided tumors were associated with visible blood in stools and changes in bowel habits. Visible blood in stools was significantly associated with lower TNM-stage, whereas abdominal pain, general and acute symptoms were associated with higher TNM-stage.

Association of right-sided tumors with high thymidine phosphorylase gene expression levels and the response to oral uracil and tegafur/leucovorin chemotherapy among patients with colorectal cancer

PURPOSE

To identify useful predictive factors for the response to 5-fluorouracil (5-FU)/leucovorin (LV) and oral uracil and tegafur (UFT)/LV chemotherapy among patients with colorectal cancer, we investigated the association between the gene expression levels of pyrimidine and folate metabolism-related enzymes in colorectal cancer (CRC) tissues and the response to UFT/LV neoadjuvant chemotherapy.

METHODS

The subjects were 76 CRC patients who were scheduled to undergo surgery. UFT (300 mg/m(2)/day) and LV (75 mg/body/day) were administered for 2 weeks before surgery. Biopsy samples were endoscopically obtained before drug administration. The gene expression levels of 14 genes in the biopsy samples were quantitatively evaluated using a real-time polymerase chain reaction (RT-PCR) assay.

RESULTS

Fifteen patients (19.7 %) with marked pathological regression were judged to be responders. Thymidine phosphorylase (TP) gene expression levels among the responders were significantly higher than those among the non-responders. Right-sided tumors with high TP gene expression levels were associated with a significantly higher response rate to UFT/LV chemotherapy than left-sided tumors.

CONCLUSIONS

TP gene expression levels in primary CRC tissues and the primary tumor site may be useful predictors of the efficacy of oral UFT/LV chemotherapy.

Analysis of colorectal cancer morphology in relation to sex, age, location, and family history

BACKGROUND

Studies of colorectal cancer (CRC) have suggested different mechanisms of carcinogenesis in men and women, young and old patients, right- and left sided tumors, and sporadic and familial tumors. These differences might be reflected in morphology.

METHODS

CRCs from 1613 patients operated on in 2004-2006 in Sweden were histologically reviewed. Morphology was examined in relation to sex, age groups, location, and family history.

RESULTS

Tumors in the right colon were larger, of higher stage, more often poorly differentiated, more mucin-producing, more often had a peritumoral lymphocytic infiltrate and a high level of tumor-infiltrating lymphocytes (TILs), and more seldom had an infiltrating margin than tumors in the left colon and rectum (p < 0.0001 for most features). Young patients (<60 years) more seldom had multiple tumors but more often had perineural invasion, an infiltrative tumor margin, and high-stage tumors. Three features, TILs, medullary tumors, and invasive tumor margin, were related to sex. Only vascular invasion was related to familiality.

CONCLUSION

Location is the factor that has the most influence on tumor morphology. The results support the idea that different carcinogenic mechanisms may be involved in the right and left colon. Age is the most important determinant for the presence of multiple tumors and is a crucial factor for the aggressiveness of the disease.

Prognostic factors for locoregional recurrences in colon cancer

BACKGROUND

There is increased interest in locoregional recurrences of rectal cancer. Despite comparable locoregional recurrence rates in colon cancer, only a few studies on locoregional recurrences among colon cancer patients have been published. This study was designed to identify prognostic factors for locoregional recurrences among patients with colon cancer in the Netherlands.

METHODS

The study population was composed of patients who underwent radical surgical resections for invasive colon carcinoma, diagnosed in three regions of the Netherlands from 2000 to 2003. The Kaplan-Meier method was used to calculate 5-year locoregional recurrence rates (LRR). Conditional hazard rates were estimated by the life-table method. Multivariate Cox regression analyses were performed to identify prognostic factors and to calculate a Locoregional Recurrence Risk Score (LRRS).

RESULTS

In total 127 of 2,282 patients developed locoregional recurrences within 5 years (LRR 6.4%). The risk of developing a locoregional recurrence was highest at 0.5-1 year after surgery. Patients with left-sided tumors, T3-T4 tumors, and positive lymph nodes and those who did not receive adjuvant chemotherapy were more likely to develop locoregional recurrences. Four risk groups based on the LRRS were defined. Five-year LRR was 2.5% for the very low-risk group and 25.1% for the high-risk group.

CONCLUSIONS

Although the locoregional recurrence rate in this study was relatively low, it remains a considerable problem. Identifying individual patients who might benefit from adjuvant chemotherapy may reduce the locoregional recurrence rate.