Colorectal cancer screening for average-risk adults: 2018 guideline update from the American Cancer Society

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.

Screening flexible sigmoidoscopy versus colonoscopy for reduction of colorectal cancer mortality

PURPOSE

Colonoscopy and flexible sigmoidoscopy are both recommended colorectal cancer (CRC) screening strategies, but their relative effectiveness is unclear. We sought to evaluate the ability of each of these two modalities to reduce CRC mortality.

METHODS

We conducted a case-control study using the Surveillance, Epidemiology, and End Results (SEER)-Medicare database. Cases were persons aged 70-85 years who died of CRC and were matched to up to three non-CRC controls. Receipt of endoscopy was ascertained from Medicare claims and endoscopy indication assigned using a validated algorithm. Conditional logistic regression models were developed to estimate the association between screening colonoscopy or sigmoidoscopy and CRC mortality. We conducted secondary analyses by race, sex, and endoscopist characteristics, and with varying duration of the look-back period.

RESULTS

In the initial analysis using all available look-back years, screening flexible sigmoidoscopy was associated with a 35% reduction in CRC mortality (OR 0.65, 95% CI 0.48, 0.89), while screening colonoscopy was associated with a 74% reduction (OR 0.26, 95% CI 0.23, 0.30). Sigmoidoscopy was not associated with any reduction in proximal CRC mortality. The association between colonoscopy and reduced CRC mortality was stronger in the distal than the proximal colon. Results were similar in analyses using a 5-year look-back period.

CONCLUSIONS

Screening colonoscopy was associated with greater reductions in CRC mortality than screening sigmoidoscopy, and with a greater reduction in the distal than the proximal colon. These results provide additional information on the relative benefits of screening for CRC with sigmoidoscopy and colonoscopy.

Cost-Effectiveness and National Effects of Initiating Colorectal Cancer Screening for Average-Risk Persons at Age 45 Years Instead of 50 Years

BACKGROUND & AIMS

The American Cancer Society has recommended initiating colorectal cancer (CRC) screening at age 45 years instead of 50 years. We estimated the cost effectiveness and national effects of adopting this recommendation.

METHODS

We compared screening strategies and alternative resource allocations in a validated Markov model. We based national projections on screening participation rates by age and census data.

RESULTS

Screening colonoscopy initiation at age 45 years instead of 50 years in 1000 persons averted 4 CRCs and 2 CRC deaths, gained 14 quality-adjusted life-years (QALYs), cost $33,900/QALY gained, and required 758 additional colonoscopies. These 758 colonoscopies could instead be used to screen 231 currently unscreened 55-year-old persons or 342 currently unscreened 65-year-old persons, through age 75 years. These alternatives averted 13-14 CRC cases and 6-7 CRC deaths and gained 27-28 discounted QALYs while saving $163,700-$445,800. Improving colonoscopy completion rates after abnormal results from a fecal immunochemical test yielded greater benefits and savings. Initiation of fecal immunochemical testing at age 45 years instead of 50 years cost $7700/QALY gained. Shifting current age-specific screening rates to 5 years earlier could avert 29,400 CRC cases and 11,100 CRC deaths over the next 5 years but would require 10.7 million additional colonoscopies and cost an incremental $10.4 billion. Improving screening rates to 80% in persons who are 50-75 years old would avert nearly 3-fold more CRC deaths at one third the incremental cost.

CONCLUSIONS

In a Markov model analysis, we found that starting CRC screening at age 45 years is likely to be cost effective. However, greater benefit, at lower cost, could be achieved by increasing participation rates for unscreened older and higher-risk persons.

STK11 p.G270W: A Novel Mutation Detected in a Case of MSI High Mixed Medullary-Mucinous Carcinoma of the Transverse Colon

BACKGROUND/AIM

To report a case of mixed medullary/mucinous adenocarcinoma with unusual mutational gene profile.

PATIENTS AND METHODS

A 79-year-old female was diagnosed with a colorectal carcinoma of the transverse colon. The diagnostic work-up of this case included thorough clinicopathological evaluation, immunohistochemistry and next generation Sequencing.

RESULTS

The clinicopathological evaluation showed a tumor with morphological features of both medullary and mucinous colorectal carcinoma. Immunohistochemistry revealed the loss of DNA mismatch repair proteins. NGS showed that the medullary component of this tumor had a novel STK11 p.G270W mutation, which was not present in the mucinous component. Both the medullary and mucinous components also had BRAF V600E and AKT1 (pE17K) mutations.

CONCLUSION

We report a novel mutation STK11 (p.G270W), in medullary carcinoma of the colon with an associated mucinous component.

Colorectal cancer screening from 45 years of age: Thesis, antithesis and synthesis

Colorectal cancer incidence and mortality in patients younger than 50 years are increasing, but screening before the age of 50 is not offered in Europe. Advanced-stage diagnosis and mortality from colorectal cancer before 50 years of age are increasing. This is not a detection-bias effect; it is a real issue affecting the entire population. Three independent computational models indicate that screening from 45 years of age would yield a better balance of benefits and risks than the current start at 50 years of age. Experimental data support these predictions in a sex- and race-independent manner. Earlier screening is seemingly affordable, with minimal impediments to providing younger adults with colonoscopy. Indeed, the American Cancer Society has already started to recommend screening from 45 years of age in the United States. Implementing early screening is a societal and public health problem. The three independent computational models that suggested earlier screening were criticized for assuming perfect compliance. Guidelines and recommendations should be derived from well-collected and reproducible data, and not from mathematical predictions. In the era of personalized medicine, screening decisions might not be based solely on age, and sophisticated prediction software may better guide screening. Moreover, early screening might divert resources away from older individuals with greater biological risks. Finally, it is still unknown whether early colorectal cancer is part of a continuum of disease or a biologically distinct disease and, as such, it might not benefit from screening at all. The increase in early-onset colorectal cancer incidence and mortality demonstrates an obligation to take actions. Earlier screening would save lives, and starting at the age of 45 years may be a robust screening option.

Long noncoding RNA Linc02023 regulates PTEN stability and suppresses tumorigenesis of colorectal cancer in a PTEN-dependent pathway

Phosphatase and tensin homolog (PTEN), one of the most frequently mutated tumor suppressor genes in human cancer, is pivotal in the progression of colorectal cancer. Therefore, the regulation of PTEN has emerged as a theme of intense research in tumor biology. This study aims to show that long noncoding RNA (lncRNA) Linc02023 aberrant downregulation in colorectal cancer correlates positively with the expression of PTEN and CDKN2B but negatively with the tumor size in patients and xenografted mouse models. The gain- and loss-of-function investigation reveals that Linc02023 suppresses the proliferation of colorectal cancer cells in vitro and in vivo with apoptosis promotion and cell cycle rearrangement. Mechanistically, Linc02023 specifically binds to PTEN and blocks its interaction with and ubiquitination by WWP2, stabilizing it and suppressing its downstream expression. In conclusion, this study demonstrates that lncRNA Linc02023 may serve as a novel therapeutic target by restoring the PTEN tumor suppressor activity.

Incidence of Advanced Colorectal Neoplasia in Individuals With Untreated Diminutive Colorectal Adenomas Diagnosed by Magnifying Image-Enhanced Endoscopy

OBJECTIVES

Because of the increasing number of detected diminutive colorectal adenomas, the "diagnose-and-do-not-resect" approach has recently attracted attention as an alternative to resection. We evaluated the cumulative incidence of advanced colorectal neoplasia (ACN) in individuals with untreated diminutive adenomas and compared this incidence in individuals without adenomas.

METHODS

Data from 1,378 individuals who underwent first screening colonoscopy (CS) and at least one follow-up CS without polypectomy were analyzed. Patients with no adenomas or with only nonadvanced diminutive adenomas (<5 mm) diagnosed by magnifying image-enhanced endoscopy were scheduled to undergo a follow-up CS within 5 years after the initial CS without treatment. The participants were divided into 2 groups: those with untreated diminutive adenomas (group A) and those with no adenomas (group B). The cumulative incidence of ACN and the hazard ratio were assessed using Gray's test and the Fine and Gray model.

RESULTS

During the median follow-up period of 60.9 months, 21 ACNs were detected. The 5-year cumulative incidences of ACN in group A (n = 361) and group B (n = 1,017) were 1.4% (95% confidence interval [CI]: 0.5-3.4) and 0.8% (95% CI: 0.3-1.7), respectively, without a statistically significant difference (P = 0.23). No ACNs developed from unresected adenomas. The smoking status was significantly associated with the incidence of ACN, and the hazard ratio for ACN in group A vs group B adjusted for smoking status was 1.43 (95% CI: 0.52-3.90; P = 0.48).

DISCUSSION

The low 5-year cumulative incidence of ACN suggests the potential to adopt the "diagnose-and-do-not-resect" strategy as an alternative option for diminutive adenomas not requiring excessive surveillance.

Current state and future direction of screening tool for colorectal cancer

As the second-most-common cause of cancer death, colorectal cancer (CRC) has been recognized as one of the biggest health concerns in advanced countries. The 5-year survival rate for patients with early-stage CRC is significantly better than that for patients with CRC detected at a late stage. The primary target for CRC screening and prevention is advanced neoplasia, which includes both CRC itself, as well as benign but histologically advanced adenomas that are at increased risk for progression to malignancy. Prevention of CRC through detection of advanced adenomas is important. It is, therefore, necessary to develop more efficient detection methods to enable earlier detection and therefore better prognosis. Although a number of CRC diagnostic methods are currently used for early detection, including stool-based tests, traditional colonoscopy, etc., they have not shown optimal results due to several limitations. Hence, development of more reliable screening methods is required in order to detect the disease at an early stage. New screening tools also need to be able to accurately diagnose CRC and advanced adenoma, help guide treatment, and predict the prognosis along with being relatively simple and non-invasive. As part of such efforts, many proposals for the early detection of colorectal neoplasms have been introduced. For example, metabolomics, referring to the scientific study of the metabolism of living organisms, has been shown to be a possible approach for discovering CRC-related biomarkers. In addition, a growing number of high-performance screening methodologies could facilitate biomarker identification. In the present, evidence-based review, the authors summarize the current state as recognized by the recent guideline recommendation from the American Cancer Society, US Preventive Services Task Force and the United States Multi-Society Task Force and discuss future direction of screening tools for colorectal cancer. Further, we highlight the most interesting publications on new screening tools, like molecular biomarkers and metabolomics, and discuss these in detail.

Dietary Inflammatory Index and Odds of Colorectal Cancer and Colorectal Adenomatous Polyps in A Case-Control Study from Iran

BACKGROUND

Chronic inflammation is implicated in the development of colorectal cancer (CRC) and its precursor; colorectal adenomatous polyps (CAP). Some dietary factors are important triggers for systemic inflammation. Therefore, the present study aimed to investigate the association between the dietary inflammatory index (DII®) and the risk of CRC and CAP in an Iranian case-control study.

METHODS

134 newly diagnosed CRC patients, 130 newly diagnosed CAP patients, and 240 hospitalized controls were recruited using convenience sampling. Energy-adjusted DII (E-DII) scores were computed based on dietary intake assessed using a reproducible and valid 148-item food frequency questionnaire. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CI) after adjusting for confounders.

RESULTS

The E-DII score ranged between -4.23 (the most anti-inflammatory score) to +3.89 (the most pro-inflammatory score). The multivariable-adjusted ORs for participants in the 3rd tertile compared to the 1st tertile was 5.08 (95%CI: 2.70-9.56; P-trend < 0.0001) for CRC and 2.33 (95% CI: 1.30-4.02; P-trend = 0.005) for CAP.

CONCLUSIONS

Our findings suggest that more pro-inflammatory diets, indicated by higher E-DII scores, might increase the risk of both CRC and CAP. Future steps should include testing these associations in a prospective setting in Iran.

Awareness of Colorectal Cancer and Attitudes Towards Its Screening Guidelines in Lebanon

Background:

Screening for colorectal cancer (CRC) provides an effective strategy for early detection and prevention of the disease; however, global screening rates are still low.

Purpose:

This study aims at assessing the awareness of CRC risk factors, warning signs, and attitudes towards CRC guidelines and screening modalities, in order to identify the barriers to and correlates of CRC screening in the Lebanese population.

Methods:

A self-administered questionnaire was distributed to 371 participants in the largest health care medical center in Lebanon. A validated 12- and 9-item Cancer Awareness Measurement questionnaire was used to assess participants’ awareness of CRC risk factors and warning signs.

Results:

83% and 67% of participants were not aware of CRC risk factors and warning signs, respectively, 15% have previously undergone CRC screening, 56% were aware of the necessity for screening, and 43% were willing to undergo screening. Factors affecting awareness of the necessity for CRC screening, past screening and willingness to screen included awareness of risk factors and warning signs, undergoing regular physician check-ups, having a family physician as a primary source of knowledge of CRC, and knowing a family member or friend diagnosed with CRC. Barriers to screening were related to participants’ evaluation of the screening technique and misconceptions about this disease.

Conclusion:

Serious active measures should be taken by health care sectors, authoritative groups, primary care physicians, and awareness campaigns to fill the gap in awareness of this disease and to alleviate the barriers and misconceptions around it.

Study of Promoter Methylation Patterns of HOXA2, HOXA5, and HOXA6 and Its Clinicopathological Characteristics in Colorectal Cancer

Research on DNA methylation offers great potential for the identification of biomarkers that can be applied for accurately assessing an individual's risk for cancer. In this article, we try to find the ideal epigenetic genes involved in colorectal cancer (CRC) based on a CRC database and our CRC cohort. The top 20 genes with an extremely high frequency of hypermethylation in CRC were identified in the latest database. Remarkably, 3 HOXA genes were included in this list and ranked at the top. The percentage of methylation in the HOXA5, HOXA2, and HOXA6 genes in CRC were up to 67.62, 58.36, and 31.32%, respectively, and ranked first in CRC among all human tumor tissues. Paired colorectal tumor samples and adjacent non-tumor colorectal tissue samples and four CRC cell lines were selected for MethylTarget™ assays. The results demonstrated that CRC tissues and cells had a stronger methylation status around the 3 HOXA gene promoter regions compared with adjacent non-tumor colonic tissue samples. The Receiver operator characteristic curve (ROC) curves for HOXA genes show excellent diagnostic ability in distinguishing tissue from healthy individuals and CRC patients, especially for Stage I patients (AUC = 0.9979 in HOXA2, 0.9309 in HOXA5, and 0.8025 in HOXA6). An association analysis between the methylation pattern of HOXA genes and clinical indicators was performed and found that HOXA2 methylation was significantly associated with age, N, stage, M, lymphovascular invasion, perineural invasion, lymph node number. HOXA5 methylation was associated with age, T, M, stage, and tumor status, and HOXA6 methylation was associated with age and KRAS mutation. Notably, we found that the highest methylation of HOXA5 and HOXA2 occurs in the early stages of colorectal cancer tissues such as stage I, N0, MO, and non-invasive tissues. The methylation levels declined as tumors progressed. However, methylation level at any stage of the tumor was still significantly higher than in normal tissues (p < 0.0001). The mRNA of the 3 HOXA genes was downregulated in early tumor stages due to hypermethylation of CpG islands adjacent to the promoters of the genes. In addition, hypermethylation of HOXA5 and HOXA6 mainly occurred in patients < 60 years old and with MSI-L, MSS, CIMP.L and non-CIMP tumors. Together, this suggests that epigenetic silencing of 3 adjacent HOXA genes may be an important event in the progression of colorectal cancer.

Trends in Incidence and Stage at Diagnosis of Colorectal Cancer in Adults Aged 40 Through 49 Years, 1975-2015

This cancer epidemiology study uses SEER program data to describe trends in stage of incident colorectal cancer in adults aged 40-49 years between 1975 and 2015 to understand if apparent increases in incidence are due to earlier detection or true increases in risk.

Treatment patterns and survival differ between early-onset and late-onset colorectal cancer patients: the patient outcomes to advance learning network

PURPOSE

Our objective was to describe differences in treatment patterns and survival between early-onset (< 50 years old) and late-onset colorectal cancer (CRC) patients in community-based health systems.

METHODS

We used tumor registry and electronic health record data to identify and characterize patients diagnosed with adenocarcinoma of the colon or rectum from 2010 to 2014 at six US health systems in the patient outcomes to advance learning (PORTAL) network. We used logistic regression to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) comparing the distribution of tumor characteristics and treatment patterns in early-onset versus late-onset CRC. Cox regression models were used to estimate adjusted hazard ratios (HRs) and CIs comparing survival between early- and late-onset CRC patients.

RESULTS

There were 1,424 early-onset and 10,810 late-onset CRC cases in our analyses. Compared to late-onset CRC, early-onset CRC was significantly associated with advanced-stage disease, high-grade histology, signet ring histology, and rectal or left colon location. After adjusting for differences in tumor and patient characteristics, early-onset patients were more likely than late-onset patients to have > 12 lymph nodes examined (OR 1.60, CI 1.37-1.87), to receive systemic therapy (chemotherapy or immunotherapy) within 6 months of diagnosis (OR 2.84, CI 2.40-3.37), and to have a reduced risk of CRC-specific death (HR 0.66, CI 0.56-0.79).

CONCLUSIONS

Early-onset CRC is associated with aggressive tumor characteristics, distal location, and systemic therapy use. Despite some adverse risk factors, these patients tend to have better survival than older onset patients.

Colorectal Cancer in the Young: Does Screening Make Sense?

PURPOSE OF REVIEW

Colorectal cancer (CRC) screening is recommended to reduce CRC mortality. This review outlines key factors to consider when recommending screening, including disease burden, screening benefits and harms, and remaining knowledge gaps.

RECENT FINDINGS

In response to increasing rates of CRC incidence among younger (age < 50 years) adults, the American Cancer Society published guidelines in May 2018 recommending average-risk CRC screening beginning at age 45 (vs. 50) years. Rates of young-onset CRC have increased in the USA since the early 1990s. However, there is very little empirical evidence of screening effectiveness in younger adults, and few studies have reported harms of routine screening in this age group. Further, we know little about the natural history of CRC in younger adults. Uncertainty surrounding the efficacy of CRC screening in younger adults suggests the benefits may be small. Precision cancer screening-or modified screening regimens based on risk-may improve the balance of screening benefits and harms beyond conventional age-based strategies.

Colorectal cancer in young patients: a retrospective cohort study in a single institution

BACKGROUND

Young onset colorectal cancer is on the rise, with a disproportionate increase in incidence among young people, both in Australia and internationally. Current national guidelines for bowel cancer screening in average risk individuals include only patients greater than 50 years of age. It is well recognized that colorectal cancer is a highly treatable malignancy when detected at an early stage, and timely diagnosis yields a greater than 90% chance of cure and survival. The aims of this study were to define the clinical presentations leading to colonoscopy in young patients and assess the incidence of malignancy in this group.

METHODS

This is a retrospective cohort study including all patients ≤35 years of age without any baseline indication for early bowel cancer surveillance that underwent colonoscopy at Caboolture Hospital from January 2017 to April 2018.

RESULTS

A total of 224 patients underwent colonoscopy in the study period. A total of 210 (93.8%) had symptoms including rectal bleeding (51.7%), altered bowel habit (25.9%), abdominal pain (10.3%) and symptomatic anaemia (6.7%) prior to colonoscopy. Two cases of invasive adenocarcinoma were identified (0.89%, P < 0.01), both of which were symptomatic and were defined as stage IIIB disease on histopathology.

CONCLUSION

In a theoretically low-risk population, the incidence of malignancy was nearly 1%. More advanced disease at diagnosis may be due to a delay in investigating these patients due to an overall low suspicion of cancer in young individuals. As such, investigation should be offered early to young patients presenting with any warning symptoms.

Failure of 3 different methods and biopsy sites to diagnose a patient with invasive colorectal cancer: A case report

RATIONALE

Colorectal cancer is one of the most commonly diagnosed cancers worldwide, and the majority arise from neoplastic adenomatous polyps. Bladder involvement in colorectal cancer is uncommon and found in approximately 3% of the cases, most commonly in sigmoid and rectal tumors and the diagnosis is classically based on biopsies of affected tissues.

PATIENT CONCERNS

A 68-year-old male with no significant past medical history underwent diagnostic colonoscopy for abdominal distension and constipation with positive fecal occult blood test ordered by the primary care physician.

DIAGNOSIS

Colonoscopy showed a sigmoid mass with biopsy finding of tubulovillous adenoma. Laparoscopy was performed for sigmoid colonic resection, but as the mass was large, a diverting loop colostomy and multiple biopsies were performed revealing tubulovillous adenoma again. Postoperative workup revealed right hydronephrosis, and cystoscopy was performed confirming bladder wall invasion with biopsies showing benign bladder wall tissue with no evidence of dysplasia or malignancy. Furthermore, computed tomography (CT)-guided core-needle biopsies of the colonic mass were performed but revealed adenomatous colonic mucosa without evidence of carcinoma.

INTERVENTION

Definitive surgical en bloc excision of the tumor and anterior bladder wall was performed with urology team until grossly free margins were attained. Final pathology revealed well-differentiated mucinous adenocarcinoma arising from a preexisting tubulovillous adenoma with direct invasion of the bladder wall.

OUTCOMES

The patient's postoperative recovery was uneventful, and he was discharged 2 weeks postoperatively with planned adjuvant chemotherapy.

LESSONS

This case represents a classical presentation of invasive colorectal cancer. Perioperative workup, however, was confounded by failure of open, cystoscopic, and CT-guided biopsies to establish a tissue diagnosis for directed therapy. Upon literature review, evidence exists to support our approach to this unique dilemma.

Cancer screening in the United States, 2019: A review of current American Cancer Society guidelines and current issues in cancer screening

Each year, the American Cancer Society publishes a summary of its guidelines for early cancer detection, data and trends in cancer screening rates, and select issues related to cancer screening. In this issue of the journal, the current American Cancer Society cancer screening guidelines are summarized, and the most current data from the National Health Interview Survey are provided on the utilization of cancer screening for men and women and on the adherence of men and women to multiple recommended screening tests.

Optimal age for screening colonoscopy: a modeling study

BACKGROUND AND AIMS

Recent guidelines on colorectal cancer (CRC) screening recommend starting screening earlier than before. We performed a simulation study to examine and compare the optimal ages to have once-only screening colonoscopy and repeated colonoscopies.

METHODS

A Markov model was set up using data from the German national screening colonoscopy registry to simulate the natural history of the adenoma-carcinoma process. CRC deaths and years of potential life lost (YPLL) for a hypothetical unscreened 50-year-old German population were estimated for a single screening colonoscopy or 2 or 3 screening colonoscopies with 10-year intervals at various ages.

RESULTS

One single screening colonoscopy performed between 50 and 65 years of age was expected to reduce CRC death by 49% to 69% and YPLL by 51% to 68%. An inverted U-shaped association was found between screening age and proportion of CRC deaths or YPLL prevented. The optimal age for once-only colonoscopy that yielded the highest reductions in YPLL was around 54 years for men and 56 years for women. Estimates were approximately 6 to 8 years higher when proportions of CRC deaths prevented were examined. For 2 or 3 screening colonoscopies, the optimal starting age fell to around 50 years or even younger for both genders.

CONCLUSIONS

Based on the YPLL estimates, in a high CRC incidence and high life expectancy country like Germany, the optimal age for once-only screening colonoscopy is around 55 years and possibly slightly younger for men than for women. When 2 or more screening colonoscopies are offered with 10-year intervals, screening should start at age 50 at the latest or possibly even younger for both genders.

Pre-cancerous colon polyps in the young - incidental adenoma detection in average-risk persons forty and younger

Of 166 consecutive diagnostic colonoscopies performed on persons aged forty and under (excluding those at an increased risk of colon neoplasms) by a single gastroenterologist in community practice with an Adenoma Detection Rate (ADR) approaching 70% in average-risk screening colons in persons over fifty, 34 had incidentally detected colon adenomas and 38 had serrated polyps. We suggest routine tabulation of incidentally detected polyps in young people to better understand colon neoplasm biology and plan prevention strategies.

Confounders in Adenoma Detection at Initial Screening Colonoscopy: A Factor in the Assessment of Racial Disparities as a Risk for Colon Cancer

Background and Aims

The incidence and mortality of colorectal cancer is persistently highest in Black/African-Americans in the United States. While access to care, barriers to screening, and poverty might explain these findings, there is increased interest in examining biological factors that impact the colonic environment. Our group is examining biologic factors that contribute to disparities in development of adenomas prospectively. In preparation for this and to characterize a potential patient population, we conducted a retrospective review of initial screening colonoscopies in a cohort of patients.

Methods

A retrospective review was performed on initial average risk screening colonoscopies on patients (age 45-75 years) during 2012 at three institutions. Descriptive statistics and multivariable logistic regression models were used to examine the relationship between potential risk factors and the detection of adenomas.

Results

Of the 2225 initial screening colonoscopies 1495 (67.2%) were performed on Black/African-Americans and 566 (25.4%) on Caucasians. Multivariable logistic regression revealed that older age, male sex, current smoking and teaching gastroenterologists were associated with higher detection of adenomas and these were less prevalent among Black/African-Americas except for age. Neither race, ethnicity, BMI, diabetes mellitus, HIV nor insurance were associated with adenoma detection.

Conclusion

In this sample, there was no association between race and adenoma detection. While this may be due to a lower prevalence of risk factors for adenomas in this sample, our findings were confounded by a lower detection rate by consultant gastroenterologists at one institution. The study allowed us to rectify the problem and characterize patients for future trials.

Factors predicting the colorectal adenoma detection rate in colonoscopic screening of a Chinese population: A prospective study

Colorectal cancer has high incidence and mortality. Early diagnosis could increase patient survival, but early diagnosis has been poor in China for the past decades. The purpose of this study is to assess the polyp detection rate (PDR) and adenoma detection rate (ADR) by colonoscopy in a Chinese population, and to determine the risk factors for adenoma.This prospective study at Sichuan Provincial People's Hospital evaluated patients who underwent colonoscopy in September 2017 to February 2018. Basic information, exact insertion and withdrawal times, PDR, and ADR were assessed. Risk factors for colorectal adenoma in the adenoma-positive and adenoma-negative groups (based on pathology) were assessed by multivariable logistic regression analysis.A total of 1058 procedures with 767 polyps were analyzed. The overall PDR and ADR were 36.96% (391/1058) and 24.67% (261/1058), respectively. Occurrence of adenoma was associated with age, gender, body mass index (BMI), family history of colon cancer, personal history of adenoma, diabetes mellitus, and tobacco use. There was a significant association between withdrawal time and ADR (P < .001). In the multivariable analysis, age (OR = 1.041, 95%CI 1.028-1.055; P < .001), insertion time (OR = 0.999, 95%CI 0.998-1.000; P = .009), withdrawal time (OR = 1.009, 95%CI 1.007-1.011; P < .001), personal history of adenoma (OR = 2.572, 95%CI 1.115-5.932; P = .027), and diabetes mellitus (OR = 2.221, 95%CI 1.084-4.549; P = .029) were risk factors for colorectal adenoma detection.In a Chinese population, ADR increases with age, withdrawal time, a personal history of adenoma, and diabetes. Age, insertion and withdrawal times, and a personal history of adenoma may independently predict colorectal adenoma detection.

Meeting report from the joint IARC-NCI international cancer seminar series: a focus on colorectal cancer

Despite significant progress in our understanding of the etiology, biology and genetics of colorectal cancer, as well as important clinical advances, it remains the third most frequently diagnosed cancer worldwide and is the second leading cause of cancer death. Based on demographic projections, the global burden of colorectal cancer would be expected to rise by 72% from 1.8 million new cases in 2018 to over 3 million in 2040 with substantial increases anticipated in low- and middle-income countries. In this meeting report, we summarize the content of a joint workshop led by the National Cancer Institute and the International Agency for Research on Cancer, which was held to summarize the important achievements that have been made in our understanding of colorectal cancer etiology, genetics, early detection and treatment and to identify key research questions that remain to be addressed.

Incidence and characteristics of young-onset colorectal cancer in the United States: An analysis of SEER data collected from 1988 to 2013

BACKGROUND

The incidence of colorectal cancer (CRC) has significantly increased in adults < 50 years old who are below the screening age.

OBJECTIVES

The primary objective was to evaluate the age-standardized incidence (ASI) of young-onset CRC from 1988 to 2013. The secondary objective was to assess factors associated with cancer-specific death (CSD).

METHODS

We accessed data of 64,854 CRC patients (20-49 years old) from the United States Surveillance, Epidemiology, and End Results Program (SEER) database.

RESULTS

A gradual increase in the ASI of CRC in the study population was found: from 3.59/100,000 males in 1988 to 5.21/100,000 males in 2013, and from 3.15/100,000 females in 1988 to 4.45/100,000 females in 2013. ASI adjusted by race revealed a relatively pronounced increase in the white population compared to African American and other races, with an increase from 3.07/100,000 persons in 1988 to 4.79/100,000 persons in 2013. Males had a 19% higher likelihood of CRC-related death compared to females [hazard ratio (HR) = 1.19, 95% confidence interval (CI): 1.16-1.23], and African American had a 1.34-fold higher likelihood of CRC-related death compared to whites (95% CI: 1.28-1.39). CRC-related death was significantly higher in patients with signet ring-cell histology (HR = 1.56, 95% CI: 1.45-1.68), compared to patients with adenocarcinoma. Male gender, and advanced stage predicted a higher likelihood of CRC-related death in African Americans compared to the whole population. Signet ring-cell histology, advanced stage, and advanced grade were significantly associated with CRC-related death in African-American patients.

CONCLUSION

This study corroborates emerging data that the (ASI) of young-onset CRC is increasing. It also identified factors associated with cancer-specific death in this population that may aid in targeting screening strategies for adults < 50 years old.

Trends of colorectal cancer incidence and mortality rates from 2003 to 2014 in Italy

OBJECTIVE

To evaluate the trends of colorectal cancer (CRC) incidence and mortality rates from 2003 to 2014 in Italy by age groups and regions.

METHODS

We used the data of 48 cancer registries from 17 Italian regions to estimate standardized incidence and mortality rates overall and by sex, age groups (<50, 50-69, 70+ years), and geographic area (northwest, northeast, center, south, and islands). Time trends were expressed as annual percent change in rates (APC) with 95% confidence intervals (95% CI).

RESULTS

Incidence rates decreased from 104.3 (2003) to 89.9 × 100,000 (2014) in men and from 64.3 to 58.4 × 100,000 in women. Among men, incidence decreased during 2007-2010 (APC -4.0, 95% CI -6.0 to -1.9) and 2010-2014 (APC -0.7, 95% CI -1.4 to 0.0), while in women it linearly decreased during the whole period (APC -1.1, 95% CI -1.4 to -0.8). Mortality rates showed a linear reduction both in men (APC -0.7, 95% CI -1.0 to -0.3) and women (APC -0.9, 95% CI -1.2 to -0.6) and decreased respectively from 41.1 to 39.2 × 100,000 and from 24.6 to 23.1 × 100,000. In the 50- to 69-year-old range (screening target age), incidence showed a prescreening increase, followed by a peak after screening started, and a decline thereafter. Incidence and mortality rates significantly decreased in all areas but in the south and islands, where incidence increased and mortality remained stable.

CONCLUSIONS

A renewed commitment by all regional health systems to invest in primary (i.e., lifestyle) and secondary (i.e., screening programs) prevention is of utmost importance.

Familial colorectal cancer risk in half siblings and siblings: nationwide cohort study

OBJECTIVE

To explore the risk of colorectal cancer in family members of patients with colorectal cancer, with an emphasis on subtypes of second degree relatives, especially half siblings, which were lacking in the literature.

DESIGN

Ambidirectional cohort study.

SETTING

Nationwide Swedish Family Cancer Data (record linkage).

PARTICIPANTS

All people residing in Sweden and born after 1931, with their biological parents, totalling >16 million individuals (follow-up: 1958-2015); of those with clear genealogy, 173 796 developed colorectal cancer.

MAIN OUTCOME MEASURES

Lifetime (0-79 years) cumulative risk and standardised incidence ratio of colorectal cancer among first degree relatives and second degree relatives.

RESULTS

The overall lifetime cumulative risk of colorectal cancer in siblings of patients was 7%, which represents a 1.7-fold (95% confidence interval 1.6 to 1.7; n=2089) increase over the risk in those without any family history of colorectal cancer. A similarly increased lifetime cumulative risk (6%) was found among half siblings (standardised incidence ratio 1.5, 95% confidence interval 1.3 to 1.8; n=140). The risk in people with colorectal cancer in both a parent and a half sibling (standardised incidence ratio 3.6, 2.4 to 5.0; n=32) was close to the risk in those with both an affected parent and an affected sibling (2.7, 2.4 to 3.0; n=396). Family history of colorectal cancer in only one second degree relative other than a half sibling (without any affected first degree relatives), such as a grandparent, uncle, or aunt, showed minor association with the risk of colorectal cancer.

CONCLUSION

Family history of colorectal cancer in half siblings is similarly associated with colorectal cancer risk to that in siblings. The increase in risk of colorectal cancer among people with one affected second degree relative was negligible, except for half siblings, but the risk was substantially increased for a combination of family history in one affected second degree relative and an affected first degree relative (or even another second degree relative). These evidence based findings provide novel information to help to identify people at high risk with a family history of colorectal cancer that can potentially be used for risk adapted screening.

Clinical and molecular characterization of early-onset colorectal cancer

BACKGROUND

Colorectal cancer (CRC) incidence is increasing in adults younger than 50 years. This study evaluated clinical and molecular features to identify those features unique to early-onset CRC that differentiate these patients from patients 50 years old or older.

METHODS

Baseline characteristics were evaluated according to the CRC onset age with 3 independent cohorts. A fourth cohort was used to describe the impact of age on the consensus molecular subtype (CMS) prevalence.

RESULTS

This retrospective review of more than 36,000 patients with CRC showed that early-onset patients were more likely to have microsatellite instability (P = .038), synchronous metastatic disease (P = .009), primary tumors in the distal colon or rectum (P < .0001), and fewer BRAF V600 mutations (P < .001) in comparison with patients 50 years old or older. Patients aged 18 to 29 years had fewer adenomatous polyposis coli (APC) mutations (odds ratio [OR], 0.56; 95% confidence interval [CI], 0.35-0.90; P = .015) and an increased prevalence of signet ring histology (OR, 4.89; 95% CI, 3.23-7.39; P < .0001) in comparison with other patients younger than 50 years. In patients younger than 40 years, CMS1 was the most common subtype, whereas CMS3 and CMS4 were uncommon (P = .003). CMS2 was relatively stable across age groups. Early-onset patients with inflammatory bowel disease were more likely to have mucinous or signet ring histology (OR, 5.54; 95% CI, 2.24-13.74; P = .0004) and less likely to have APC mutations (OR, 0.24; 95% CI, 0.07-0.75; P = .019) in comparison with early-onset patients without predisposing conditions.

CONCLUSIONS

Early-onset CRC is not only distinct from traditional CRC: special consideration should be given to and further investigations should be performed for both very young patients with CRC (18-29 years) and those with predisposing conditions. The etiology of the high rate of CMS1 in patients younger than 40 years deserves further exploration.

Performance of a MethyLight assay for methylated SFRP2 DNA detection in colorectal cancer tissue and serum

BACKGROUND

Colorectal cancer is one of the five most common cancers in China, and its incidence is steadily increasing. An accurate and non-invasive screening method is needed to increase the population uptake of colorectal cancer screening. Secreted frizzled-related protein 2 ( SFRP2) has been found to be hypermethylated in most colorectal cancer patients, and it may fulfill the role of a non-invasive biomarker for colorectal cancer screening.

METHODS

Methylation status of SFRP2 was examined in 17 cancer tissues and paired adjacent paracancer tissues by a new SFRP2 MethyLight assay, which was also used to test the serum of 62 patients with colorectal cancer and 55 normal individuals.

RESULTS

The limit of detection of the SFRP2 MethyLight assay was about 200 pg per reaction. The SFRP2 methylation level was higher in 94.1% colorectal cancer tissues than in paired adjacent paracancer tissues ( P<0.001). The sensitivity and specificity of SFRP2 for detecting colorectal cancer in serum were 69.4% (95% confidence interval (CI) 56.2, 80.1%) and 87.3% (95% CI 74.9, 94.3%), respectively.

CONCLUSION

SFRP2 methylation in serum has the potential to be a non-invasive biomarker for colorectal cancer screening.

Performance Characteristics of Fecal Immunochemical Tests for Colorectal Cancer and Advanced Adenomatous Polyps: A Systematic Review and Meta-analysis

BACKGROUND

Studies report inconsistent performance of fecal immunochemical tests (FITs) for colorectal cancer (CRC) and advanced adenomas.

PURPOSE

To summarize performance characteristics of FITs for CRC and advanced adenomas in average-risk persons undergoing screening colonoscopy (reference standard) and to identify factors affecting these characteristics.

DATA SOURCES

Ovid MEDLINE, PubMed, Embase, and the Cochrane Library from inception through October 2018; reference lists of studies and reviews.

STUDY SELECTION

Two reviewers independently screened records to identify published English-language prospective or retrospective observational studies that evaluated FIT sensitivity and specificity for colonoscopic findings in asymptomatic, average-risk adults.

DATA EXTRACTION

Two authors independently extracted data and evaluated study quality.

DATA SYNTHESIS

Thirty-one studies (120 255 participants; 18 FITs) were included; all were judged to have low to moderate risk of bias. Performance characteristics depended on the threshold for a positive result. A threshold of 10 µg/g resulted in sensitivity of 0.91 (95% CI, 0.84 to 0.95) and a negative likelihood ratio of 0.10 (CI, 0.06 to 0.19) for CRC, whereas a threshold of greater than 20 µg/g resulted in specificity of 0.95 (CI, 0.94 to 0.96) and a positive likelihood ratio of 15.49 (CI, 9.82 to 22.39). For advanced adenomas, sensitivity was 0.40 (CI, 0.33 to 0.47) and the negative likelihood ratio was 0.67 (CI, 0.57 to 0.78) at 10 µg/g, and specificity was 0.95 (CI, 0.94 to 0.96) and the positive likelihood ratio was 5.86 (CI, 3.77 to 8.97) at greater than 20 µg/g. Studies had low to high heterogeneity, depending on the threshold. Although several FITs had adequate performance, sensitivity and specificity for CRC for 1 qualitative FIT were 0.90 and 0.91, respectively, at its single threshold of 10 µg/g; positive and negative likelihood ratios were 10.13 and 0.11, respectively. Comparison of 3 FITs at 3 thresholds was inconclusive: CIs overlapped, and the comparisons were across rather than within studies.

LIMITATIONS

Only English-language studies were included. Incomplete reporting limited quality assessment of some evidence. Performance characteristics are for 1-time rather than serial testing.

CONCLUSION

Single-application FITs have moderate to high sensitivity and specificity for CRC, depending on the positivity threshold. Sensitivity of 1-time testing for advanced adenomas is low, regardless of the threshold.

PRIMARY FUNDING SOURCE

Department of Medicine, Indiana University School of Medicine.

A novel 4-gene prognostic signature for hypermutated colorectal cancer

Background

Hypermutated colorectal cancer (CRC) reportedly accounts for 15%–17% of all cases of CRC. However, the proportion and number of patients with hypermutated CRC cannot be unappreciated. Additionally, therapy options for these patients differ from those for CRC patients, with a greater potential benefit from immunotherapy.

Materials and methods

We sequenced the tumor mucosa of CRC patients with >24 months of follow-up data at our center and identified mutation profiles of hypermutated CRC as a training data set (Zhejiang University [ZJU]); we then collected patients from The Cancer Genome Atlas (TCGA) as a validation data set. Recurrently mutated genes were combined to calculate a compound score via Cox proportional hazards model. Patients with higher-than-median scores were segregated as the high-risk group. Outcomes were analyzed by Kaplan–Meier and Cox regression analyses using Python (3.6.0) and R (3.4.0).

Results

We constructed a 4-gene signature (ACVR2A, APC, DOCK2, and POLE), with training in 45 hypermutated patients at ZJU and validation in 24 hypermutated patients from TCGA. Patients in the high-risk group showed poor survival (adjusted HR =9.85, 95% CI: 2.07–46.81, P=0.004). Further subgroup analysis was performed for stage II and III colon cancer (HR =10.91, 95% CI: 1.36–87.5, P=0.005) and high microsatellite instability (MSI-H) CRC (HR =12.57, 95% CI: 1.57–100.69, P=0.002) subgroups, which verified that our signature is universal. We then compared our prognostic signature with other risk factors (including MSI status, POLE driver mutation, BRAF-p.V600E, tumor mutational burden, and TNM staging). The results proved that our 4-gene signature is better than the other risk factor for prognosis in hypermutated CRC.

Conclusion

Our 4-gene signature is a good predictor of survival for hypermutated CRC, and this signature is powerful in stage II and III colon cancer and MSI-H CRC. Future prospective studies are needed to confirm the power of the 4-gene signature in patients receiving immunotherapy.

Progress of colorectal cancer screening in United States: Past achievements and future challenges

The United States has seen progress with colorectal cancer with both falling incidence and mortality rates. Factoring into this decline, the significance of early detection and removal of precancerous lesions through screening must be underscored. With the advancement of screening modalities, attention has been directed towards optimizing the quality of screening and detecting adenomas. Colorectal cancer screening has been a major agenda item for national gastroenterology societies, culminating in a major victory with passage of the Balanced Budget Act that allowed for Medicare coverage of colorectal cancer screening. Colonoscopy as the primary screening modality was solidified in the 1990s after landmark studies demonstrated its superiority over modalities for detecting precancerous polyps. Despite progress, colorectal cancer screening disparities between race and gender continue to exist. Legislative efforts are on-going and include the SCREEN Act and Dent Act that aim to further improve access to screening. The National Colorectal Cancer Roundtable has launched colorectal cancer screening initiatives targeting at risk populations. Today, the current goal of these initiatives is to reach colorectal screening rate of 80% of eligible patients by 2018. With these initiatives, efforts to narrow the gaps in screening disparities and lower overall mortality have been prioritized and continued by the medical community. This review article details colorectal cancer screening progress to date and highlights major studies and initiatives that have solidified its success in the United States.

Impact of the Affordable Care Act on Colorectal Cancer Screening, Incidence, and Survival in Kentucky

BACKGROUND

Kentucky ranks first in the US in cancer incidence and mortality. Compounded by high poverty levels and a high rate of medically uninsured, cancer rates are even worse in Appalachian Kentucky. Being one of the first states to adopt the Affordable Care Act (ACA) Medicaid expansion, insurance coverage markedly increased for Kentucky residents. The purpose of our study was to determine the impact of Medicaid expansion on colorectal cancer (CRC) screening, diagnosis, and survival in Kentucky.

STUDY DESIGN

The Kentucky Cabinet for Health and Family Services and the Kentucky Cancer Registry were queried for individuals (≥20 years old) undergoing CRC screening (per US Preventative Services Task Force) or diagnosed with primary invasive CRC from January 1, 2011 to December 31, 2016. Colorectal cancer screening rates, incidence, and survival were compared before (2011 to 2013) and after (2014 to 2016) ACA implementation.

RESULTS

Colorectal cancer screening was performed in 930,176 individuals, and 11,441 new CRCs were diagnosed from 2011 to 2016. Screening for CRC increased substantially for Medicaid patients after ACA implementation (+230%, p < 0.001), with a higher increase in screening among the Appalachian (+44%) compared with the non-Appalachian (+22%, p < 0.01) population. The incidence of CRC increased after ACA implementation in individuals with Medicaid coverage (+6.7%, p < 0.001). Additionally, the proportion of early stage CRC (stage I/II) increased by 9.3% for Appalachians (p = 0.09), while there was little change for non-Appalachians (-1.5%, p = 0.60). Colorectal cancer survival was improved after ACA implementation (hazard ratio 0.73, p < 0.01), particularly in the Appalachian population with Medicaid coverage.

CONCLUSIONS

Implementation of Medicaid expansion led to a significant increase in CRC screening, CRC diagnoses, and overall survival in CRC patients with Medicaid, with an even more profound impact in the Appalachian population.

Young-age onset colorectal cancer in Brazil: Analysis of incidence, clinical features, and outcomes in a tertiary cancer center

BACKGROUND

Recent studies report increasing incidence of colorectal cancer (CRC) in the young-age population, but data concerning clinical behavior, pathologic findings, and prognosis are controversial for this group. Early recognition of CRC in young patients is a challenge and diagnosis at advanced stage is clearly associated with worse outcomes.

MATERIALS AND METHODS

We retrospectively reviewed medical records of 5806 patients diagnosed with CRC between January/2011 and November/2016 and identified 781 patients aged less than 50-years-old.

RESULTS

We found an absolute increasing in the incidence of CRC in patients <50 years old of 1.88%-2.23% annually, with a relative increasing of 35.3% between 2011 and 2016. Median age was 42 years, 57.4% were female and 20.9% reported family history of CRC. Left-sided tumors were more frequent and the majority of patients were symptomatic. The most common stages at diagnosis were III (34.1%) and IV (37.3%). The median overall survival (OS) for stage IV was 25 months (95% CI 20.7-29.3) and was not reached for Stages I-III (P < 0.001). Family history of CRC was independently associated with better OS in stage IV(P = 0.02). For stages I-III, wild-type KRAS, family history of CRC, and absence of angiolymphatic invasion were associated with better OS (P = 0.02, P = 0.01 and P < 0.001, respectively).

CONCLUSIONS

In our cohort, the incidence of early-onset CRC is increasing over the past years. Young patients were more likely to be diagnosed with metastatic disease, left-sided and/or rectum site and symptoms at presentation. These findings highlight the emerging importance of young-age onset CRC and the need to discuss strategies to early diagnosis.

Healthy behavioral choices and cancer screening in persons living with HIV/AIDS are different by sex and years since HIV diagnosis

PURPOSE

The prevalence of non-AIDS-related malignancies is on the rise among people aging with HIV population, but the evidence on healthy behaviors including cancer screening practices in this population subgroup is extremely limited. Therefore, we investigated the prevalence of healthy behaviors and sex-specific cancer screening among persons living with HIV, by sex and time since HIV diagnosis.

METHODS

We included 517 persons living with HIV from the Florida Cohort. Data were obtained from the baseline and follow-up questionnaires, electronic medical records, and Enhanced HIV/AIDS Reporting System. The prevalence of self-reported, age-appropriate cancer screening (anal, colorectal, prostate, breast, and cervical), and healthy behaviors (sustaining healthy body weight, refraining from smoking and alcohol and engaging in physical activity) was compared by sex and years since HIV diagnosis (≤ 13 vs. > 13 years).

RESULTS

In the analyses by sex, females were more likely to be obese than males (56.5% vs. 22.2%, p < 0.0001). Distribution of healthy behaviors did not differ by time since diagnosis among males and females. In the analysis of age-appropriate screening among males, 64.8% never had an anal Pap-smear, 36.2% never had a colonoscopy, and 38.9% never had prostate cancer screening. In the analysis of age-appropriate screening among females, 50.0% never had an anal Pap-smear, 46.5% never had a colonoscopy, 7.9% never had a cervical Pap-smear, and 12.7% never had a mammogram. The difference in anal Pap-smear by sex was statistically significant (p < 0.0001). Among males, the age-adjusted prevalence of never having a colonoscopy was higher in those who had HIV for ≤ 13 years (50.8% vs. 30.6%, p = 0.03).

CONCLUSION

The prevalence of selected healthy behaviors and cancer screening differed by sex and/or years since HIV diagnosis suggesting a need for tailored cancer prevention efforts among persons living with HIV via long-term sex-specific interventions.

Demographic trends and KRAS/BRAFV600E mutations in colorectal cancer patients of South China: A single-site report

The incidence of colorectal cancer (CRC) is increasing in China. Here, we aimed to evaluate the latest demographic trends and KRAS/BRAF mutations status of Chinese CRC. Five thousand five hundred and forty-six CRC patients diagnosed from 2010 to 2017 were involved. KRAS exon 2 and BRAF^V600E mutations were detected by Sanger sequencing and high-resolution melting analysis or allelic-specific probe method. Gene mutation profiles and clinicopathologic characteristics of 5495 patients were analyzed. The joinpoint regression model was used to predict the demographic data in 2018. We found KRAS exon 2 and BRAF^V600E mutation rates were 37.7 and 2.8% in CRC patients. Tumors with KRAS exon 2 mutations were more likely to be present in female and patients aged older than 75 years, right colon and have well-differentiated histology. Tumors with BRAF^V600E mutations were more likely to be present in the female, right colon and have poorly differentiated histology. From 2010 to 2017, the percentage of colon cancer and tubular adenocarcinoma in CRC increased substantially (from 39.3 to 51.8%, from 78.6 to 93.4%, respectively). The percentage of right colon cancer increased from 18.3 to 20.5%, which predictively may keep at 22.6% in 2018. The rise trends for patients with moderate differentiation tumor or KRAS exon 2 mutated tumor were apparent (from 50.3 to 78.6%, from 32.8 to 39.7%, respectively). In conclusion, in recent 8 years, there is a shift to the colon, especially right colon in the incidence of Chinese CRC. Moreover tubular adenocarcinoma is becoming the primary histology type.

Early Detection for Colorectal Cancer: ASCO Resource-Stratified Guideline

PURPOSE

To provide resource-stratified, evidence-based recommendations on the early detection of colorectal cancer in four tiers to clinicians, patients, and caregivers.

METHODS

American Society of Clinical Oncology convened a multidisciplinary, multinational panel of medical oncology, surgical oncology, surgery, gastroenterology, health technology assessment, cancer epidemiology, pathology, radiology, radiation oncology, and patient advocacy experts. The Expert Panel reviewed existing guidelines and conducted a modified ADAPTE process and a formal consensus-based process with additional experts (Consensus Ratings Group) for two round(s) of formal ratings.

RESULTS

Existing sets of guidelines from eight guideline developers were identified and reviewed; adapted recommendations form the evidence base. These guidelines, along with cost-effectiveness analyses, provided evidence to inform the formal consensus process, which resulted in agreement of 75% or more.

CONCLUSION

In nonmaximal settings, for people who are asymptomatic, are ages 50 to 75 years, have no family history of colorectal cancer, are at average risk, and are in settings with high incidences of colorectal cancer, the following screening options are recommended: guaiac fecal occult blood test and fecal immunochemical testing (basic), flexible sigmoidoscopy (add option in limited), and colonoscopy (add option in enhanced). Optimal reflex testing strategy for persons with positive screens is as follows: endoscopy; if not available, barium enema (basic or limited). Management of polyps in enhanced is as follows: colonoscopy, polypectomy; if not suitable, then surgical resection. For workup and diagnosis of people with symptoms, physical exam with digital rectal examination, double contrast barium enema (only in basic and limited); colonoscopy; flexible sigmoidoscopy with biopsy (if contraindication to latter) or computed tomography colonography if contraindications to two endoscopies (enhanced only).

Effect of flexible sigmoidoscopy screening on colorectal cancer incidence and mortality: long-term follow-up of the randomised US PLCO cancer screening trial

BACKGROUND

Screening flexible sigmoidoscopy reduces incidence and mortality of colorectal cancer. Previously reported results from the Prostate, Lung, Colorectal, and Ovarian Cancer (PLCO) screening trial had a median follow-up of 12 years. Whether the benefit is sustained over the long term and remains so in both sexes and all age groups is uncertain. We report long-term results after an additional 5 years of follow-up.

METHODS

Participants in the PLCO trial were recruited from the general population in the catchment areas of ten screening centres across the USA, without previous diagnosis of a prostate, lung, colorectal, or ovarian cancer or current cancer treatment. From 1993 to 2001, participants aged 55-74 years were randomly assigned to usual care or flexible sigmoidoscopy at baseline and again at 3 years or 5 years. Randomisation was done within blocks and stratified by centre, age, and sex. The primary endpoint was cause-specific mortality and secondary endpoints included incidence and tumour staging; cause of death was determined without knowledge of study arm. In this analysis, we assessed incidence and mortality rates overall, by time-period, and by combinations of sex, age at baseline (55-64 years/65-74 years), location (distal/proximal), and stage, on an intent-to-treat basis. This trial is registered with ClinicalTrials.gov, number NCT00002540.

FINDINGS

After a median follow-up of 15·8 years (IQR 13·2-18·0) for incidence and 16·8 years (14·4-18·9) for mortality, the incidence of colorectal cancer was significantly lower in the intervention arm (1461 cases; 12·55 per 10 000 person-years) than with usual care (1761 cases; 15·33 per 10 000 person-years; relative risk [RR] 0·82, 95% CI 0·76-0·88). Similarly, mortality was lower in the intervention arm (417 deaths; 3·37 per 10 000 person-years) than the usual care arm (549; 4·48 per 10 000 person-years; RR 0·75, 95% CI 0·66-0·85). The reduction in mortality was limited to the distal colon, with no significant effect in the proximal colon. Reductions in incidence were significantly larger in men than women (pinteraction=0·04) and reductions in mortality were significantly larger in the older age group (65-74 years vs 55-64 years at baseline; pinteraction=0·01).

INTERPRETATION

Reductions in colorectal cancer incidence and mortality from flexible sigmoidoscopy screening are sustained over the long term. Differences by sex and age should be examined in other ongoing trials of colorectal cancer screening to help clarify if different screening strategies would achieve greater risk reduction.

FUNDING

Extended follow-up was funded under NIH contract HHSN261201600007I.

Increasing Trend in Young-Onset Colorectal Cancer in Asia: More Cancers in Men and More Rectal Cancers

BACKGROUND

The incidence of young-onset colorectal cancer (CRC) is reported to be increasing in the Western world. There are no population-based studies assessing the trend across Asia.

METHODS

We performed a multinational cohort study involving four Asian countries/regions, namely Taiwan, Korea, Japan, and Hong Kong. The magnitude and direction of trend in the incidence of young-onset CRC (age < 50) were quantified using Joinpoint Regression Program to estimate average annual percentage change (AAPC).

RESULTS

In Taiwan (1995-2014), incidence of young-onset CRC significantly increased in both men (colon cancer: 4.9-9.7 per 100,000; rectal cancer: 4.0-8.3 per 100,000) and women (colon cancer: 5.1-9.7 per 100,000; rectal cancer: 3.8-6.4 per 100,000). In Korea (1999-2014), incidence of young-onset CRC significantly increased in both men (colon cancer: 5.0-10.4 per 100,000; rectal cancer: 4.9-14.0 per 100,000) and women (colon cancer: 4.1-9.6 per 100,000; rectal cancer: 4.1-9.1 per 100,000). The most pronounced change was observed with male rectal cancer, increasing by 3.9% per year in Taiwan (AAPC + 3.9, 95% confidence interval + 3.3 to +4.5, P < 0.05) and 6.0% per year in Korea (AAPC +6.0, 95% confidence interval + 4.5 to +7.6, P < 0.05). Only a significant increase in rectal cancer was noted in Japan (male rectal cancer: 7.2-10.1 per 100,000, female rectal cancer 4.7-6.7 per 100,000) and Hong Kong (male rectal cancer: 4.4-7.0 per 100,000).

CONCLUSIONS

Increasing trend in young-onset CRC is not limited to the Western world. This finding may have implications on screening program for CRC in these countries/regions.