Proximal shift of colorectal cancer along with aging

Colorectal Cancer After Screening Colonoscopy: 10-Year Incidence by Site and Detection Rate at First Repeat Colonoscopy

INTRODUCTION

We aimed to describe cumulative colorectal cancer (CRC) incidence after screening colonoscopy stratified by tumor location, age, and sex as well as CRC detection rate at first repeat colonoscopy.

METHODS

Using the German Pharmacoepidemiological Research Database, we included persons with screening colonoscopy and assessed cumulative CRC incidence after baseline screening colonoscopy with snare polypectomy (cohort 1) and without polypectomy (cohort 2). We also determined the CRC detection rate at first repeat colonoscopy by time since screening colonoscopy.

RESULTS

Overall, 1,095,381 persons were included. The 10-year cumulative CRC incidence was 1.5% in cohort 1 and 0.6% in cohort 2. The proportion of proximal CRC increased with age: In women of cohort 1, 47% of CRCs in the age group 55-64 years were proximal (men: 42%) while in the age group 65-74 years, this proportion was 55% (men: 49%). In cohort 2, similar patterns were observed. In cohort 1, the CRC detection rate at first repeat colonoscopy among persons examined within 6-8 years after screening colonoscopy was more than twice as high compared with those examined within 4-6 years (1.7% vs 0.8%).

DISCUSSION

Among persons followed up after screening colonoscopy, we observed a steadily increasing predominance of proximal CRC, and this shift showed distinct patterns by age and sex. Because our study suggests higher CRC detection rates among persons with a later repeat colonoscopy, the role of delayed surveillance and the benefit of a reminder system should be explored.

Cyclomodulins and Hemolysis in E. coli as Potential Low-Cost Non-Invasive Biomarkers for Colorectal Cancer Screening

The frequent occurrence of E. coli positive for cyclomodulins such as colibactin (CLB), the cytotoxic necrotizing factor (CNF), and the cytolethal distending factor (CDT) in colorectal cancer (CRC) patients published so far provides the opportunity to use them as CRC screening markers. We examined the practicability and performance of a low-cost detection approach that relied on culture followed by simplified DNA extraction and PCR in E. coli isolates recovered from 130 CRC patients and 111 controls. Our results showed a statistically significant association between CRC and the presence of colibactin genes clbB and clbN, the cnf gene, and newly, the hemolytic phenotype of E. coli isolates. We also observed a significant increase in the mean number of morphologically distinct E. coli isolates per patient in the CRC cohort compared to controls, indicating that the cyclomodulin-producing E. coli strains may represent potentially preventable harmful newcomers in CRC patients. A colibactin gene assay showed the highest detection rate (45.4%), and males would benefit from the screening more than females. However, because of the high number of false positives, practical use of this marker must be explored. In our opinion, it may serve as an auxiliary marker to increase the specificity and/or sensitivity of the well-established fecal immunochemical test (FIT) in CRC screening.

Low curcumin concentration enhances the anticancer effect of 5-fluorouracil against colorectal cancer

BACKGROUND

Colon cancer treatments include surgery, radiotherapy, and chemotherapy. Chemotherapy using 5-fluorouracil (5-FU) has been widely applied to treat colorectal cancer (CRC). However, it is important to explore the use of chemotherapy drugs in combination with other agents to decrease severe adverse effects.

PURPOSE

This study aimed to investigate the effects of curcumin in combination with 5-FU on the proliferation, migration, and apoptosis of CRC SW620 cell line both in vitro and in vivo.

METHODS

Flow cytometry was used to study the effect of curcumin on chemotherapy-induced apoptosis in CRC cells. The mechanism of curcumin's enhanced antitumor effect in vivo was investigated using gene knockdown, TUNEL, western blot, qRT-PCR and immunohistochemistry.

RESULTS

The results showed a synergistic effect of the two compounds on CRC cells. Considerable reduction in the proliferation and migration of SW620 cells was observed in the combination treatment group. Significantly increased apoptosis rate extended the survival of immunodeficient mice in the combination group as compared to that of the 5-FU group (p < 0.05). The results showed that curcumin significantly inhibited pERK signaling and downregulated L1 expression in SW620 cells.

CONCLUSIONS

We conclude that curcumin promotes chemosensitivity of CRC cells to 5-FU by downregulating L1 expression. Our findings provide experimental evidence for the synergism between curcumin and 5-FU, which can be utilized in clinical applications for reducing the toxicity and adverse effects of 5-FU.

Disease characteristics and treatment patterns of Chinese patients with metastatic colorectal cancer: a retrospective study using medical records from China

Background

Colorectal cancer (CRC) is the third most prevalent cancer in China but few large-scale studies were conducted to understand CRC patients. The current study is aimed to gain a real-world perspectives of CRC patients in China.

Methods

Using electronic medical records of sampled patients between 2011 and 2016 from 12 hospitals in China, a retrospective cohort study was conducted to describe demographics and disease prognosis of CRC patients, and examine treatment sequences among metastatic CRC (mCRC) patients. Descriptive, comparative and survival analyses were conducted.

Results

Among mCRC patients (3878/8136, 48%), the fluorouracil, leucovorin, and oxaliplatin (FOLFOX) and other oxaliplatin-based regimens were the most widely-used first-line treatment (42%). Fluorouracil, leucovorin, irinotecan (FOLFIRI) and other irinotecan-based regimens dominated the second-line (40%). There was no a dominated regimen for the third-line. The proportion of patients receiving chemotherapy with targeted biologics increased from less than 20% for the first- and second- lines to 34% for the third-line (p < 0.001). The most common sequence from first- to second-line was from FOLFOX and other oxaliplatin-based regimens to FOLFIRI and other irinotecan-based regimens (286/1200, 24%).

Conclusions

Our findings reflected a lack of consensus on the choice of third-line therapy and limited available options in China. It is evident o continue promoting early CRC diagnosis and to increase the accessibility of treatment options for mCRC patients. As the only nationwide large-scale study among CRC and mCRC patients before more biologics became available in China, our results can also be used as the baseline to assess treatment pattern changes before and after more third-line treatment were approved and covered into the National Health Insurance Plan in China between 2017 and 2018.

Risk factors for colorectal cancer significantly vary by anatomic site

Objective

To conduct an anatomic site-specific case–control study of candidate colorectal cancer (CRC) risk factors.

Design

Case–control study of US veterans with >1 colonoscopy during 1999–2011. Cases had cancer registry-identified CRC at colonoscopy, while controls were CRC free at colonoscopy and within 3 years of colonoscopy. Primary outcome was CRC, stratified by anatomic site: proximal, distal, or rectal. Candidate risk factors included age, sex, race/ethnicity, body mass index, height, diabetes, smoking status, and aspirin exposure summarised by adjusted ORs and 95% CIs.

Results

21 744 CRC cases (n=7017 rectal; n=7039 distal; n=7688 proximal) and 612 646 controls were included. Males had significantly higher odds relative to females for rectal cancer (OR=2.84, 95% CI 2.25 to 3.58) than distal cancer (OR=1.84, 95% CI 1.50 to 2.24). Relative to whites, blacks had significantly lower rectal cancer odds (OR=0.88, 95% CI 0.82 to 0.95), but increased distal (OR=1.27, 95% CI 1.19 to 1.37) and proximal odds (OR=1.62, 95% CI 1.52 to 1.72). Diabetes prevalence was more strongly associated with proximal (OR=1.29, 95% CI 1.22 to 1.36) than distal (OR=1.15, 95% CI 1.08 to 1.22) or rectal cancer (OR=1.12, 95% CI 1.06 to 1.19). Current smoking was more strongly associated with rectal cancer (OR=1.81, 95% CI 1.68 to 1.95) than proximal cancer (OR=1.53, 95% CI 1.43 to 1.65) or distal cancer (OR=1.46, 95% CI 1.35 to 1.57) compared with never smoking. Aspirin use was significantly more strongly associated with reduced rectal cancer odds (OR=0.71, 95% CI 0.67 to 0.76) than distal (OR=0.85, 95% CI 0.81 to 0.90) or proximal (OR=0.91, 95% CI 0.86 to 0.95).

Conclusion

Candidate CRC risk factor associations vary significantly by anatomic site. Accounting for site may enable better insights into CRC pathogenesis and cancer control strategies.

Prevalence and risk factors of colorectal cancer in Asia

Globally, colorectal cancer (CRC) is a substantial public health burden, and it is increasingly affecting populations in Asian countries. The overall prevalence of CRC is reported to be low in Asia when compared with that in Western nations, yet it had the highest number of prevalent cases. This review described the prevalence of CRC in Asia according to the International Agency for Research on Cancer from World Health Organization (WHO) database and summarized its major risk factors. Non-modifiable factors include genetic factors, ethnicity, age, gender, family history and body height; smoking, alcohol drinking, weight, Westernized diet, physical inactivity, chronic diseases and microbiota were involved in environmental factors. These risk factors were separately discussed in this review according to published literature from Asian countries. CRC screening has been playing an important role in reducing its disease burden. Some recommendations on its screening practices have been formulated in guidelines for Asia Pacific countries.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Risk factors for advanced colorectal neoplasms in the proximal colon in 6218 subjects undergoing complete colonoscopy

BACKGROUND AND AIM

Proximal migration of colonic lesion has been observed; however, risk factors of lesions in the proximal colon remain uncertain. This study aimed to investigate risk factors of lesions in the proximal colon.

METHODS

Consecutive subjects with complete colonoscopy were included. The primary outcome was risk factors associated with advanced neoplasm (AN) and serrated lesion in the proximal colon. Age, gender, first-degree relative (FDR) with colorectal cancer (CRC), smoking, alcohol consumption, body mass index, hypertension, diabetes, ischemic heart disease, and the use of aspirin, non-steroidal anti-inflammatory drug, and anticoagulants were fitted into a regression model, with reference to subjects without colonic finding. Results were measured by odds ratio (OR) with 95% confidence interval (CI).

RESULTS

Among 6218 subjects (mean age 56.65 ± 6.15 years; 46.8% male), 352 (5.7%) had AN; 809 (13.0%) had serrated lesions, and 3648 (58.7%) had no colonic finding. There were 148 (2.4%) and 235 (3.8%) subjects having AN and serrated lesion in the proximal colon. Age ≥ 50 (OR: 13.30; 95% CI: 1.85-95.76), male gender (OR: 1.82; 95% CI: 1.26-2.62), FDR with CRC (OR: 2.12; 95% CI: 1.43-3.15), and hypertension (OR: 1.86; 95% CI: 1.30-2.68) were associated with AN in the proximal colon. Age ≥ 50 (OR: 5.72; 95% CI: 2.10-15.53), male gender (OR: 1.54; 95% CI: 1.15-2.05), and smoking (OR: 1.85; 95% CI: 1.23-2.79) increased risk of serrated lesions in the proximal colon.

CONCLUSION

Age ≥ 50 and male gender were associated with both proximally located AN and serrated lesion; FDR with CRC and hypertension increased the risk of proximal AN, while ever smoking increased the risk of proximal serrated lesion. FDR with CRC was not associated with serrated lesion.

Molecular evaluation of glutathione S transferase family genes in patients with sporadic colorectal cancer

AIM

To evaluate the association between polymorphisms in glutathione S transferases (GSTs) and the risk of sporadic colorectal cancer (SCRC), tumor progression and the survival of patients.

METHODS

A case-control study of 970 individuals from the Brazilian population was conducted (232 individuals from the case group with colorectal cancer and 738 individuals from the control group without a history of cancer). PCR multiplex and PCR-RFLP techniques were used to genotype the GST polymorphisms. The tumors were categorized according to the TNM classification: tumor extension (T), affected lymph nodes (N), and presence of metastasis (M). Logistic regression, multiple logistic regression and survival analysis were used to analyze the data. The results are presented in terms of odds ratio (OR) and 95% confidence interval (CI). The level of significance was set at 5% (P ≤ 0.05).

RESULTS

Age equal to or over 62 years (OR = 8.79; 95%CI: 5.90-13.09, P < 0.01) and female gender (OR = 2.91; 95%CI: 1.74-4.37; P < 0.01) were associated with increased risk of SCRC. Analysis of the polymorphisms revealed an association between the GSTM1 polymorphisms and a risk of SCRC (OR = 1.45; 95%CI: 1.06-2.00; P = 0.02), as well as between GSTT1 and a reduced risk of the disease (OR = 0.65; 95%CI: 0.43-0.98; P = 0.04). An interaction between the presence of the wild-type allele of GSTP1 Ile105Val polymorphism and tobacco consumption on risk of SCRC (OR = 2.33; 95%CI: 1.34-4.05; P = 0.05) was observed. There was an association between the GSTM1 null genotype and the presence of advanced tumors (OR = 2.33; 95%CI: 1.23-4.41; P = 0.009), as well as increased risk of SCRC in the presence of a combination of GSTT1 non-null/GSTM1 null genotypes (OR = 1.50; 95%CI: 1.03-2.19; P = 0.03) and GSTT1 non-null/GSTM1 null/GSTP1 Val* (OR = 1.85; 95%CI: 1.01-3.36, P = 0.04). Combined GSTT1 non-null/GSTM1 null genotypes (OR = 2.40; 95%CI: 1.19-4.85; P = 0.01) and GSTT1 non-null/GSTM1 null/GSTP1 Val* (OR = 2.92; 95%CI: 1.05-8.12; P = 0.04) were associated with tumor progression. Polymorphisms were not associated with the survival of patients with SCRC.

CONCLUSION

Females aged 62 years or older are more susceptible to SCRC. Polymorphisms of GSTT1 and GSTM1 null genotypes modulated the susceptibility to SCRC in the population studied.

[Surgical treatment of colorectal carcinoma in the elderly]

Colorectal carcinoma is one of the most frequent tumor entities worldwide. The treatment of elderly and mostly polymorbid patients is an outstanding challenge in view of the demographic change with a continuously aging community. Due to the demographic changes the numbers of elderly (>65 years) and very old (≥80 years) patients are steadily increasing in surgical cohorts. This has resulted in higher morbidity and mortality rates in comparison to younger patients, with increased wound healing and cardiovascular complications but with comparable numbers of anastomotic insufficiency. Multivariate analysis revealed age ≥80 years, higher ASA status and emergency operations as independent risk factors for increased in-hospital mortality. With respect to the localization of colorectal cancer a shift to the right has been observed with increasing patient age. Whether minimally invasive surgical techniques can reduce postoperative morbidity and mortality rates in elderly patients requires further evaluation. Nevertheless, a reduction of both was reported without compromising the oncological result. Elderly patients require individualized treatment modalities, which take the extent of comorbidities and personal environment into consideration. So far, the cohort of octogenarians has not been adequately considered in current guidelines; therefore, geriatric expertise is recommended to be able to make a better assessment of benefit-risk ratios, as age itself has no impact on the decision for therapy.

The association between location, age and advanced colorectal adenoma characteristics: a propensity-matched analysis

PURPOSE

Evidence supports an association between certain colorectal adenoma characteristics and predisposition to cancer. The association between anatomical location of colorectal adenoma, age and advanced adenomas needs attention. The objective of this study was to evaluate the possible association between occurrence of sporadic advanced adenomas with location and age.

MATERIALS AND METHODS

A cross-sectional study using baseline data from index colonoscopy from a randomized controlled trial evaluating chemopreventive treatment against recurrence of colorectal adenomas was performed. Inclusion criteria for patients were one adenoma of >1 cm in diameter or multiple adenomas of any size, or an adenoma of any size and familial disposition for colorectal cancer. Multivariate regression and propensity score-matched analyses were used to correlate location of adenomas and age with advanced adenoma features.

RESULTS

In this study, 2149 adenomas were removed in 1215 patients. Advanced colorectal adenomas primarily occurred in the anal part of the colon. Older age was associated with more adenomas and more oral occurrence of adenomas, as well as a higher risk of advanced adenomas. Surprisingly, specifically for the oral adenomas the risk of advanced adenoma seems to be lower for older patients compared with younger.

CONCLUSIONS

This study presents new results with regard to association between age, location of adenomas and risk of advanced adenomas. The results indicate that sigmoidoscopy for screening purposes may be obsolete, and add to the existing literature on which future guidelines for screening may be based.

Prevalence, distribution, and risk factor for colonic neoplasia in 1133 subjects aged 40-49 undergoing screening colonoscopy

BACKGROUND AND AIM

Colorectal cancer (CRC) incidence is rising among <50-year olds. The objective of this study was to determine screening colonoscopy outcomes among 40- to 49-year olds, which are currently limited.

METHODS

Asymptomatic 40- to 49-year olds underwent one time CRC screening colonoscopy at The Chinese University of Hong Kong between 2007 and 2011. Screening outcomes, including prevalence, distribution, and predictive factors for overall and specifically proximal colorectal neoplasia were determined.

RESULTS

Among 1133 ethnic Chinese, colorectal neoplasia prevalence was 20.5%. In men, distal adenomas were associated with proximal colorectal neoplasia. Men, advancing age, a first degree relative (FDR) with CRC, and diabetes mellitus were independently associated with colorectal neoplasia. A colorectal neoplasia was three times more likely to be found in a 45- to 49-year-old man with FDR of CRC compared with a 40- to 44-year-old woman without a FDR of CRC. The numbers needed to screen one colorectal neoplasia, and one advanced neoplasm in the highest risk group of 45- to 49-year-old men with FDR with CRC were 2.8 (95% CI: 2.2-4.4) and 18.5 (95% CI: 8.9-39.2), respectively.

CONCLUSIONS

Colorectal neoplasia prevalence in this 40- to 49-year-old Chinese cohort was higher than previous studies. Men, advancing age, FDR with CRC, and diabetes mellitus, can be used to risk stratify for neoplasia development. Men 45-49 years old with FDR with CRC represented the highest risk subgroup, with the lowest number needed to screen.

Colorectal cancer incidence in 5 Asian countries by subsite: An analysis of Cancer Incidence in Five Continents (1998-2007)

Colorectal cancer is the fourth most common cancer in Asia. However, the trends in colorectal cancer incidence by subsite have not been analyzed across Asian countries. We used the most recent, high quality data from 6 cancer registries for two 5-year periods, 1998-2002 and 2003-2007, from Cancer Incidence in Five Continents to estimate colorectal cancer incidence by subsite in 5 Asian countries. Cases with overlapping lesions or otherwise unspecified colon cancer were re-distributed as proximal or distal colon cancer. Age-standardized incidence rates (ASRs) per 100,000 population and incidence rate ratios from 1998 to 2002 to 2003-2007 were calculated for each subsite. For 2003-2007, men in Miyagi, Japan, had the highest ASR for cancer in the proximal colon, distal colon and rectum. Men of Jewish ancestry in Israel had a high ASR for proximal and distal colon cancer, but the lowest ASR for rectal cancer. The proportion of rectal cancer was highest among Korean men (51.39%) and lowest among Israeli women (26.6%). From 1998-2002 to 2003-2007, rectal cancer incidence did not significantly change in most registries, except for men in Miyagi, Japan, and both sexes in Korea. However, during the same period cancer incidence in the proximal and distal colon increased in most registries. In conclusion, there was substantial variation in subsite distributions of colorectal cancer in Asian registries and increases in overall incidence of colorectal cancer could be attributed to increases in colon cancer.

Intraoperative colonoscopy in patients with colorectal cancer: Review of recent developments

The use of intraoperative colonoscopy has increased alongside progress in the development of colonoscopy-associated devices and techniques, including the colonoscope itself. In the present review, we focus on four circumstances in which intraoperative colonoscopy is beneficial to colorectal surgery: (i) intraoperative determination of a tumor's location; (ii) observation of the proximal colon in cases of obstructive colorectal cancer; (iii) confirmation of the integrity of anastomosis; and (iv) novel surgical techniques that combine laparoscopic and endoscopic surgery. In light of the findings of our review, a combination of colonoscopy and surgery-especially laparoscopic surgery-is expected to facilitate the optimal handling of a variety of colorectal tumors, ranging from benign cases to advanced and obstructive cases.

Development and validation of a predictive model for detection of colorectal cancer in primary care by analysis of complete blood counts: a binational retrospective study

OBJECTIVE

The use of risk prediction models grows as electronic medical records become widely available. Here, we develop and validate a model to identify individuals at increased risk for colorectal cancer (CRC) by analyzing blood counts, age, and sex, then determine the model's value when used to supplement conventional screening.

MATERIALS AND METHODS

Primary care data were collected from a cohort of 606 403 Israelis (of whom 3135 were diagnosed with CRC) and a case control UK dataset of 5061 CRC cases and 25 613 controls. The model was developed on 80% of the Israeli dataset and validated using the remaining Israeli and UK datasets. Performance was evaluated according to the area under the curve, specificity, and odds ratio at several working points.

RESULTS

Using blood counts obtained 3-6 months before diagnosis, the area under the curve for detecting CRC was 0.82 ± 0.01 for the Israeli validation set. The specificity was 88 ± 2% in the Israeli validation set and 94 ± 1% in the UK dataset. Detecting 50% of CRC cases, the odds ratio was 26 ± 5 and 40 ± 6, respectively, for a false-positive rate of 0.5%. Specificity for 50% detection was 87 ± 2% a year before diagnosis and 85 ± 2% for localized cancers. When used in addition to the fecal occult blood test, our model enabled more than a 2-fold increase in CRC detection.

DISCUSSION

Comparable results in 2 unrelated populations suggest that the model should generally apply to the detection of CRC in other groups. The model's performance is superior to current iron deficiency anemia management guidelines, and may help physicians to identify individuals requiring additional clinical evaluation.

CONCLUSIONS

Our model may help to detect CRC earlier in clinical practice.

Evaluation of the left-to-right shift of colon tumors in Iran: Is the trend changing?

Background:

Colorectal cancer (CRC) is the second cause of cancer-related deaths worldwide. There have been several studies reporting the proximal tumor shift, especially in Western countries. In the present study, we investigated the clinicopathologic and anatomical distributions of colorectal tumors in Iranian CRC patients.

Materials and Methods:

In this retrospective cohort study, 258 patients with CRC from 2008 to 2013 were evaluated. Comparison of variables was performed using Pearson's chi-square test and Fisher's exact test depending on the nature of the data.

Results:

A total of 258 patients including 124 (48.1%) females and 134 (51.9%) males enrolled in this study. The majority of cancers were detected in the rectosigmoid, i.e., 98 (38%) followed by the left colon, i.e., 84 (32.6%) and the right colon, i.e., 76 (29.5%). In the present study, we observed the significant association between metastases, adjuvant therapy, family history, and history of inflammatory bowel disease (IBD) with tumor, node, and metastasis (TNM) staging (P < 0.001). In univariate analysis, there was a strong association between overall survival (OS) and stage II CRC (P = 0.03). However, the predictive value was lost in multivariate analysis (P = 0.145).

Conclusion:

Unlike the majority of previous studies on Iranian CRC patients, we observed a considerably higher occurrence of right-sided colon cancers (84 versus 76). Although this phenomenon did not reach the statistical significance rate, based on recent studies on Iranian population including the present one, the pattern of anatomical distribution of colorectal tumors has been changed toward the proximal colon. This requires an urgent need to provide other strategies and complementary detecting approaches in order to identify proximal tumors in Iranian CRC patients.

Distributions of colorectal cancer in two Chinese cities with contrasting colorectal cancer epidemiology

BACKGROUND AND AIM

The incidence of colorectal cancer (CRC) is rising rapidly in Chinese. We studied the anatomic distributions and characteristics of CRC in Hong Kong (HK) and Chongqing (CQ) with different CRC epidemiology.

METHODS

It was a retrospective study conducted in three large regional hospitals of the two cities. We identified all patients newly diagnosed with CRC between 2003 and 2012. The distribution and characteristics of CRC of the two cities were compared.

RESULTS

Of CRC, 3664 new cases were diagnosed within the study period. CRC was more common in men (>56%) in both cities. The mean age at diagnosis was significantly younger in CQ, the lower prevalence area, than in HK (62.1 vs 70.4 years; P < 0.001). Rectal cancer was the predominant (61.3%) cancer in CQ, but only 18% of cancers in HK were rectal cancer (P = 0.0001). Right-sided colonic cancer, however, was more common in HK than CQ (27.2% vs 17.4%; P < 0.001). Women had more right-sided colonic cancer than men in both cities (P < 0.002), and there was an age-related increase in right-sided colonic cancer in HK but not in CQ. Multivariate analysis showed that older age, female, and living in HK were independent risk factors associated with right-sided colonic cancer.

CONCLUSIONS

There are significant differences in the distribution of CRC between HK and CQ. The discrepancy may be partly accounted by older population and an increase in proximal colonic cancer, particularly in women, in HK.