Trends in colorectal cancer incidence rates in New Zealand, 1981-2004

Statistical methods for measuring trends in colorectal cancer incidence in registries: A systematic review

Background

Monitoring cancer trends in a population is essential for tracking the disease’s burden, allocating resources, and informing public health policies. This review describes variations in commonly employed methods to estimate colorectal cancer (CRC) incidence trends.

Methods

We performed a systematic literature search in four databases to identify population-based studies reporting CRC incidence trends, published between January 2010 and May 2020. We extracted and described data on methods to estimate trends and assess model validity, and the software used.

Results

This review included 145 articles based on studies conducted in five continents. The majority (93%) presented visual summaries of trends combined with absolute, relative, or annual change estimates. Fourteen (10%) articles exclusively calculated the relative change in incidence over a given time interval, presented as the percentage of change in rates. Joinpoint regression analysis was the most commonly used method for assessing incidence trends (n= 65, 45%), providing estimates of the annual percentage change (APC) in rates. Nineteen (13%) studies performed Poisson regression and 18 (12%) linear regression analysis. Age-period-cohort modeling- a type of generalized linear models- was conducted in 18 (12%) studies. Thirty-nine (37%) of the studies modeling incidence trends (n=104, 72%) indicated the method used to evaluate model fitness. The joinpoint program (52%) was the statistical software most commonly used.

Conclusion

This review identified variation in the calculation of CRC incidence trends and inadequate reporting of model fit statistics. Our findings highlight the need for increasing clarity and transparency in reporting methods to facilitate interpretation, reproduction, and comparison with findings from previous studies.

A systematic review of methods to estimate colorectal cancer incidence using population-based cancer registries

Background

Epidemiological studies of incidence play an essential role in quantifying disease burden, resource planning, and informing public health policies. A variety of measures for estimating cancer incidence have been used. Appropriate reporting of incidence calculations is essential to enable clear interpretation. This review uses colorectal cancer (CRC) as an exemplar to summarize and describe variation in commonly employed incidence measures and evaluate the quality of reporting incidence methods.

Methods

We searched four databases for CRC incidence studies published between January 2010 and May 2020. Two independent reviewers screened all titles and abstracts. Eligible studies were population-based cancer registry studies evaluating CRC incidence. We extracted data on study characteristics and author-defined criteria for assessing the quality of reporting incidence. We used descriptive statistics to summarize the information.

Results

This review retrieved 165 relevant articles. The age-standardized incidence rate (ASR) (80%) was the most commonly reported incidence measure, and the 2000 U.S. standard population the most commonly used reference population (39%). Slightly more than half (54%) of the studies reported CRC incidence stratified by anatomical site. The quality of reporting incidence methods was suboptimal. Of all included studies: 45 (27%) failed to report the classification system used to define CRC; 63 (38%) did not report CRC codes; and only 20 (12%) documented excluding certain CRC cases from the numerator. Concerning the denominator estimation: 61% of studies failed to state the source of population data; 24 (15%) indicated census years; 10 (6%) reported the method used to estimate yearly population counts; and only 5 (3%) explicitly explained the population size estimation procedure to calculate the overall average incidence rate. Thirty-three (20%) studies reported the confidence interval for incidence, and only 7 (4%) documented methods for dealing with missing data.

Conclusion

This review identified variations in incidence calculation and inadequate reporting of methods. We outlined recommendations to optimize incidence estimation and reporting practices. There is a need to establish clear guidelines for incidence reporting to facilitate assessment of the validity and interpretation of reported incidence.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01632-7.

Equity of colonoscopy provision and quality in Māori and New Zealand Europeans: a comparative retrospective study

BACKGROUND

High-quality colonoscopy is essential for investigating suspected colorectal cancer and relies on endoscopists meeting key performance indicator (KPI) targets. The rising demand for colonoscopy raises concerns that Māori populations could be under-served. This study aimed to compare rates of colonoscopy provision and colonoscopy KPIs between Māori and New Zealand (NZ) European patients.

METHODS

This retrospective comparative study was conducted at Whanganui Hospital (NZ). Consecutive colonoscopies performed between September 2016 and March 2020 were included. Primary outcome was the rate of colonoscopy provision for the population. Secondary outcomes were the colonoscopy completion rate (CCR), colonoscope withdrawal time (CWT), polyp detection rate (PDR) and adenoma detection rate (ADR). Subgroup analysis of ADR in index symptomatic colonoscopies was also performed.

RESULTS

A total of 2962 colonoscopies were analysed (385 Māori; 2577 NZ European). Rates of colonoscopy provision in participants aged ≥40 were significantly lower among Māori (6.1% versus 9.1%; P < 0.0001). The CCR (P = 1.00), CWT (P = 0.28) and PDR (P = 0.24) were similar. Whilst the ADR in the overall cohort was significantly lower in Māori (32.7% versus 40.0%; P = 0.028), this was not observed when stratified by 10-year age cohorts. The ADR was similar on subgroup analysis of index symptomatic colonoscopies (P = 0.42).

CONCLUSIONS

This study found inequities in access to colonoscopy services for Māori compared to NZ European patients. Among those that did receive colonoscopy, there were no differences in colonoscopy quality after age stratification. Improving equity will require the addition of colonoscopy provision rates to other mandatory KPIs and reporting these by ethnicity in all endoscopy units.

Effect of ethnicity and rurality on treatment delays in patients with colorectal cancer in Northland, New Zealand

BACKGROUND

Ethnic and rural disparities in medical treatment and outcomes have been demonstrated across a range of conditions, including colorectal cancer. Timely treatment and investigation of symptoms in patients with suspicion of cancer is likely to improve outcomes and patient experience. Achieving equity in timeliness of care is important in achieving the goal of equitable cancer outcomes outlined in the New Zealand cancer action plan. The aim of this study was to compare treatment times in patients with colorectal cancer, between Māori and non-Māori patients as well as urban and rural patients in Northland, New Zealand.

METHODS

All adult patients diagnosed with colorectal adenocarcinoma from 2011 to 2016 were identified using hospital coding. Further information on the primary cohort was then obtained using the hospitals electronic results system, CONCERTO. The primary outcomes of interest were differences in delays to treatment between Māori and non-Māori as well as Urban versus rural residence. Secondary outcomes of interest included rate of emergency admission and treatment by curative intent in different groups.

RESULTS

A total of 511 patients formed the primary cohort; 12% were Māori and were on average 6 years younger than non-Māori. Māori had a 6% higher emergency admission rate and a 5% higher rate of palliative treatment intent. No significant difference in treatment delay times was seen between different ethnicities or different domiciles.

CONCLUSION

Ethnicity and rurality were not shown to affect treatment delays. Further research in this area is needed to help attain equitable outcomes for patients with colorectal cancer in New Zealand.

Rightward shift in colorectal cancer: experience in 1101 patients

BACKGROUND

In the past decades the right colon cancer showed a higher incidence rate than left colon cancer. This trend is known as "proximal shift" or "rightwards shift." We evaluated rightward shift phenomenon in our region.

METHODS

We collected data from 1101 colorectal cancer patients who underwent curative surgery at Parma University Hospital from 01 January 2004 through 01 January 2018. We divided patients into seven subgroups according to the time of surgery to evaluate epidemiological changes through the years of colon cancer.

RESULTS

We found a non-linear rightward shift trend of CRC. The incidence of RCC was the 40% between 2004-2005 and 51% in the biennium 2016-2017 (60% in 2012-2013 and 57% in 2014-2015). The patients with RCC were significantly older than patients with LCC. RCCs have poor differentiated tumors. Metastatic disease showed a similar distribution both in left and right CRCs. Peritoneum was the most common metastasis location from right-sided colon cancer.

CONCLUSIONS

Data suggest the existence of two different tumor entities in CRC between right-sided colon cancer and left-sided colon cancer. The proximal shift may be a reflection of improved screening programs, diagnostic accuracy and population aging. Ethnicity, gender, diet, environment, and socioeconomic status contribute to CRC incidence and prevalence in different regions.

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

Background and purpose

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

Patients and methods

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

Results

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

Conclusion

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

Student engagement in a Human Anatomy and Physiology course: a New Zealand perspective

The population diversity of New Zealand is due to the unique fusion of indigenous peoples of Polynesian origin (Māori), western European colonization (Pākehā), and more recent (20th century) immigration from the Pacific region (Pasifika). However, disparities in tertiary education indicate that Māori and Pasifika students are more likely to drop out during their first year of study and are less likely to complete their qualification than their Pākehā peers. Higher levels of course engagement may increase first-year grades, elevate academic performance, and encourage persistence between the first and second years of study. Therefore, a Student Course Engagement Questionnaire was used to quantify engagement in a compulsory first-year undergraduate Human Anatomy and Physiology course in a New Zealand university. A data mining technique was used to assign students into a low-engagement/low-achievement cluster, and a high-engagement/high-achievement cluster. The skills, emotional, and participation-interaction components of engagement were lower in Pasifika students: these students' academic grade was lower than those of both Māori and Pākehā students. The strongest predictors of cluster membership were skills engagement and emotional engagement, suggesting that these components outweighed other aspects of course engagement. Māori and Pasifika students were overrepresented in the low-engagement/low-achievement cluster, and underrepresented in the high-engagement/high-achievement cluster. We suggest that embedding study skills within course delivery, and constantly emphasizing their importance, would likely increase student course engagement. Also, we report that both Māori and Pasifika students remain more disengaged than their Pākehā peers.

Proximal shift of colorectal cancer with increasing age in different ethnicities

Background

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

Objective

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

Materials and methods

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

Results

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

Conclusion

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

Characteristics and comparison of colorectal cancer incidence in Beijing with other regions in the world

Background

Population-based epidemiologic studies about colorectal cancer are lacking in China. This study aims to provide a basis for colorectal cancer screening and prevention, through analysis and comparisons the characteristics of the trends in colorectal cancer incidence in Beijing and selected representative regions.

RESULTS

The annual incidence rate in Beijing region increased significantly, from 9.40/100,000 in 1998 to 18.61/100,000 in 2012. The stratified rate showed that the incidence of distal colon adenocarcinoma increased substantially in men, especially in those aged > 75 years and residing in urban areas. Although the incidence rate in Beijing is still lower than in Shanghai, Jiashan, and Hong Kong in China, it is increasing rapidly. Further, the incidence rate in Beijing is lower than in New York, Oxford and Osaka, but higher than in Mumbai and Kyadondo. The incidence trend in Beijing is increasing especially in older groups, while in other regions such as New York, it is decreasing in these age groups.

Materials and Methods

Colorectal cancer incidence data were obtained from Beijing Cancer Registry and Cancer Incidence in Five Continents Plus database. All incidence rates were age-standardized according to Segi's world population. Incidence trends were characterized by calculating the annual percent changes using the Joinpoint Regression Program.

Conclusions

Compared with other regions, Beijing has a medium level of colorectal cancer incidence, however, it is increasing significantly. There are obvious differences in the cancer subsite, sex and age distributions between Beijing and other regions. Prevention and screening of colorectal cancer in Beijing should be strengthened.

Population-based study demonstrating an increase in colorectal cancer in young patients

BACKGROUND

New Zealand has among the highest rates of colorectal cancer in the world and is an unscreened population. The aim of this study was to determine the trends in incidence and tumour location in the New Zealand population before the introduction of national colorectal cancer screening.

METHODS

Data were obtained from the national cancer registry and linked to population data from 1995 to 2012. Incidence rates for colorectal cancer by sex, age (less than 50 years, 50-79 years, 80 years or more) and location (proximal colon, distal colon and rectum) were assessed by linear regression.

RESULTS

Among patients aged under 50 years, the incidence of distal colonic cancer in men increased by 14 per cent per decade (incidence rate ratio (IRR 1·14), 95 per cent c.i. 1·00 to 1·30; P = 0·042); the incidence of rectal cancer in men increased by 18 per cent (IRR 1·18, 1·06 to 1·32; P = 0·002) and that in women by 13 per cent (IRR 1·13, 1·02 to 1·26; P = 0·023). In those aged 50-79 years, there was a reduction in incidence per decade of proximal, distal and rectal cancers in both sexes. In the group aged 80 years and over, proximal cancer incidence per decade increased by 19 per cent in women (IRR 1·19, 1·13 to 1·26; P < 0·001) and by 25 per cent in men (IRR 1·25, 1·18 to 1·32; P < 0·001); among women, the incidence of distal colonic cancer decreased by 8 per cent (IRR 0·92, 0·86 to 0·98); P = 0·012), as did that of rectal cancer (IRR 0·92, 0·86 to 0·97; P = 0·005).

CONCLUSION

The increasing incidence of rectal cancer among younger patients needs to be considered when implementing screening strategies.

Effectiveness of flexible sigmoidoscopy screening in men and women and different age groups: pooled analysis of randomised trials

OBJECTIVE

 To compare the effectiveness of flexible sigmoidoscopy in screening for colorectal cancer by patient sex and age.

DESIGN

 Pooled analysis of randomised trials (the US Prostate, Lung, Colorectal and Ovarian cancer screening trial (PLCO), the Italian Screening for Colon and Rectum trial (SCORE), and the Norwegian Colorectal Cancer Prevention trial (NORCCAP)).

DATA SOURCES

 Aggregated data were pooled from each randomised trial on incidence of colorectal cancer and mortality stratified by sex, age at screening, and colon subsite (distal v proximal).

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

 Invited individuals aged 55-74 (PLCO), 55-64 (SCORE), and 50-64 (NORCCAP). Individuals were randomised to receive flexible sigmoidoscopy screening once only (SCORE and NORCCAP) or twice (PLCO), or receive usual care (no intervention).

RESULTS

 287 928 individuals were included in the pooled analysis; 115 139 randomised to screening and 172 789 to usual care. Compliance rates were 58%, 63%, and 87% in SCORE, NORCCAP, and PLCO, respectively. Median follow-up was 10.5 to 12.1 years. Screening reduced the incidence of colorectal cancer in men (relative risk 0.76; 95% confidence interval 0.70 to 0.83) and women (0.83; 0.75 to 0.92). No difference in the effect of screening was seen between men younger than 60 and those older than 60. Screening reduced the incidence of colorectal cancer in women younger than 60 (relative risk 0.71; 95% confidence interval 0.59 to 0.84), but not significantly in those aged 60 or older (0.90; 0.80 to 1.02). Colorectal cancer mortality was significantly reduced in both younger and older men, and in women younger than 60. Screening reduced colorectal cancer incidence to a similar extent in the distal colon in men and women, but there was no effect of screening in the proximal colon in older women with a significant interaction between sex and age group (P=0.04).

CONCLUSION

 Flexible sigmoidoscopy is an effective tool for colorectal cancer screening in men and younger women. The benefit is smaller and not statistically significant for women aged over 60; alternative screening methods that more effectively detect proximal tumours should be considered for these women.

Rising incidence of early-onset colorectal cancer in Australia over two decades: report and review

The average age at diagnosis for colorectal cancer (CRC) in Australia is 69, and the age-specific incidence rises rapidly after age 50 years. The incidence has stabilized or is declining in older age groups in Australia during recent decades, possibly related to the increased uptake of screening and high-risk surveillance. In the same time frame, a rising incidence of CRC in younger adults has been well-documented in the United States. This rise in incidence in the young has not been reported from other countries that share long-term exposure to westernised urban lifestyles. Using data from the Australian Institute of Health and Welfare, we examined trends in national incidence rates for CRC under age 50 years and observed that rates in people under age 40 years have been rising for the last two decades. We further performed a review of the literature regarding CRC in young adults to outline the extent of current understanding, explore potential risk factors such as obesity, alcohol, and sedentary lifestyles, and to identify the questions remaining to be addressed. Although absolute numbers might not justify a population screening approach, the dispersal of young adults with CRC across the primary health-care system decreases probability of their recognition. Patient and physician awareness, aided by stool and emerging blood-screening tests and risk profiling tools, have the potential to aid in identification of those young adults who would most benefit from a colonoscopy through early detection of CRCs or by removal of advanced polyps.

Proximal shift of colorectal cancer along with aging

INTRODUCTION

Although several reports have documented the increased incidence of right-sided colorectal cancer (CRC) in the elderly, especially in women, the gender-specific, age-related changes in the characteristics of CRCs, especially related to the cancer localization, have not been fully investigated. This study evaluated the age-related changes in the clinicopathologic features of CRCs, according to the gender.

MATERIALS AND METHODS

A total of 1059 consecutive patients with CRCs who were admitted to the authors' surgical department between February 2005 and June 2012 were retrospectively reviewed. The patients were divided into male (n = 632) and female (n = 427) groups and then according to the age group, and the correlation between the age group and the other clinicopathologic features was analyzed by univariate and multivariate analysis.

RESULTS

The number of concomitant adenomas found was significantly increased along with increasing age in men, and the presence of concomitant adenoma was the only independent age-related factor of male CRC in the multivariate analysis (P = .0044). In contrast, in women, the location of the CRC progressively shifted to the right side (proximal colon) with increasing age, and the presence of right-sided CRC was the only independent factor of female CRC in the multivariate analysis (P < .0001).

CONCLUSION

There was a significant gender-specific difference in the age-related changes in the characteristics of CRC. Increasing the number of concomitant adenomas and the shift of CRC localization to the proximal colon were the gender-specific characteristics of male and female CRC, respectively.

How many diseases are colorectal cancer?

The development of personalised therapy and mechanism-targeted agents in oncology mandates the identification of the patient populations most likely to benefit from therapy. This paper discusses the increasing evidence as to the heterogeneity of the group of diseases called colorectal cancer. Differences in the aetiology and epidemiology of proximal and distal cancers are reflected in different clinical behaviour, histopathology, and molecular characteristics of these tumours. This may impact response both to standard cytotoxic therapies and mechanism-targeted agents. This disease heterogeneity leads to challenges in the design of clinical trials to assess novel therapies in the treatment of "colorectal cancer."