Value of Size and Malignant Features of Lateral Lymph Nodes in Risk Stratification at Lateral Local Recurrence of Rectal Cancer: A National Cohort Study.

BACKGROUND: Patients with rectal cancer who have enlarged lateral lymph nodes (LLNs) have an increased risk of lateral local recurrence (LLR). However, little is known about prognostic implications of malignant features (internal heterogeneity, irregular margins, loss of fatty hilum, and round shape) on MRI and number of enlarged LLNs, in addition to LLN size. METHODS: Of the 3,057 patients with rectal cancer included in this national, retrospective, cross-sectional cohort study, 284 with a cT3-4 tumor located ≤8 cm from the anorectal junction who received neoadjuvant treatment and who had visible LLNs on MRI were selected. Imaging was reassessed by trained radiologists. LLNs were categorized based on size. Influence of malignant features and the number of LLNs on LLR was investigated. RESULTS: Of 284 patients with at least 1 visible LLN, 122 (43%) had an enlarged node (≥7.0 mm) and 157 (55%) had malignant features. Of the 122 patients with enlarged nodes, 25 had multiple (≥2). In patients with a single enlarged node (n=97), a single malignant feature was associated with a 4-year LLR rate of 0% and multiple malignant features was associated with a rate of 17% (P=.060). In the group with multiple malignant features, their disappearance on restaging was associated with an LLR rate of 13% compared with an LLR rate of 20% for persistent malignant features (P=.532). The presence of intermediate-size LLNs (5.0-6.9 mm) with at least 1 malignant feature was associated with a 4-year LLR rate of 8%; the 4-year LLR rate was 13% when the malignant features persisted on restaging MRI (P=.409). Patients with multiple enlarged LLNs had a 4-year LLR rate of 28% compared with 11% for those with a single enlarged LLN (P=.059). CONCLUSIONS: The presence of multiple enlarged LLNs (≥7.0 mm), as well as multiple malignant features in an enlarged node contribute to the risk of developing an LLR. These radiologic features can be used for clinical decision-making regarding the potential benefit of LLN dissection.

Use of 2-Stage Modeling to Identify How Colorectal Cancer Risk Changes With Period and Cohort.

Colorectal cancer (CRC) incidence rates have decreased among adults aged 50 years or older while increasing in adults under age 50 years. Understanding these trends is challenging because of the multiple related time scales of age, diagnosis period, and birth cohort. We analyzed incidence rates of rectal, distal colon, and proximal colon cancer for individuals aged 20 years or more from the Surveillance, Epidemiology, and End Results Program for diagnosis years 1978-2017. We used a 2-stage generalized linear model to determine age, period, and cohort effects for CRC incidence. We first estimated birth cohort effects among people under age 45 years. We used these results to specify prior distributions for cohort effects in a Bayesian model to estimate period effects among people aged 45 years or more. There was no evidence of period effects for people under age 45 years. Risks of rectal and distal colon cancer increased for later birth cohorts. Compared with the 1943-1952 birth cohort, the 1983-1992 birth cohort had 2.2 times the risk of rectal cancer, 1.9 times the risk of distal colon cancer, and 1.3 times the risk of proximal colon cancer. For people aged ≥45 years, period effects showed declines in CRC risk that were attributable to screening.

Locally Recurrent Rectal Cancer: Toward a Second Chance at Cure? A Population-Based, Retrospective Cohort Study.

BACKGROUND: In current practice, rates of locally recurrent rectal cancer (LRRC) are low due to the use of the total mesorectal excision (TME) in combination with various neoadjuvant treatment strategies. However, the literature on LRRC mainly consists of single- and multicenter retrospective cohort studies, which are prone to selection bias. The aim of this study is to provide a nationwide, population-based overview of LRRC after TME in the Netherlands. PATIENTS AND METHODS: In total, 1431 patients with nonmetastasized primary rectal cancer diagnosed in the first six months of 2015 and treated with TME were included from the nationwide, population-based Netherlands Cancer Registry. Data on disease recurrence were collected for patients diagnosed in these 6 months only. Competing risk cumulative incidence, competing risk regression, and Kaplan-Meier analyses were performed to assess incidence, risk factors, treatment, and overall survival (OS) of LRRC. RESULTS: Three-year cumulative incidence of LRRC was 6.4%; synchronous distant metastases (LRRC-M1) were present in 44.9% of patients with LRRC. Distal localization, R1-2 margin, (y)pT3-4, and (y)pN1-2 were associated with an increased LRRC rate. No differences in LRRC treatment and OS were found between patients who had been treated with or without prior n(C)RT. Curative-intent treatment was given to 42.9% of patients with LRRC, and 3-year OS thereafter was 70%. CONCLUSIONS: Nationwide LRRC incidence was low. A high proportion of patients with LRRC underwent curative-intent treatment, and OS of this group was high in comparison with previous studies. Additionally, n(C)RT for primary rectal cancer was not associated with differences in treatment and OS of LRRC.

Colon and rectal cancer treatment patterns and their associations with clinical, sociodemographic and lifestyle characteristics: analysis of the Australian 45 and Up Study cohort.

BACKGROUND: Colorectal cancer is the third most diagnosed cancer globally and the second leading cause of cancer death. We examined colon and rectal cancer treatment patterns in Australia. METHODS: From cancer registry records, we identified 1,236 and 542 people with incident colon and rectal cancer, respectively, diagnosed during 2006-2013 in the 45 and Up Study cohort (267,357 participants). Cancer treatment and deaths were determined via linkage to routinely collected data, including hospital and medical services records. For colon cancer, we examined treatment categories of "surgery only", "surgery plus chemotherapy", "other treatment" (i.e. other combinations of surgery/chemotherapy/radiotherapy), "no record of cancer-related treatment, died"; and, for rectal cancer, "surgery only", "surgery plus chemotherapy and/or radiotherapy", "other treatment", and "no record of cancer-related treatment, died". We analysed survival, time to first treatment, and characteristics associated with treatment receipt using competing risks regression. RESULTS: 86.4% and 86.5% of people with colon and rectal cancer, respectively, had a record of receiving any treatment ≤2 years post-diagnosis. Of those treated, 93.2% and 90.8% started treatment ≤2 months post-diagnosis, respectively. Characteristics significantly associated with treatment receipt were similar for colon and rectal cancer, with strongest associations for spread of disease and age at diagnosis (p<0.003). For colon cancer, the rate of "no record of cancer-related treatment, died" was higher for people with distant spread of disease (versus localised, subdistribution hazard ratio (SHR)=13.6, 95% confidence interval (CI):5.5-33.9), age ≥75 years (versus age 45-74, SHR=3.6, 95%CI:1.8-7.1), and visiting an emergency department ≤1 month pre-diagnosis (SHR=2.9, 95%CI:1.6-5.2). For rectal cancer, the rate of "surgery plus chemotherapy and/or radiotherapy" was higher for people with regional spread of disease (versus localised, SHR=5.2, 95%CI:3.6-7.7) and lower for people with poorer physical functioning (SHR=0.5, 95%CI:0.3-0.8) or no private health insurance (SHR=0.7, 95%CI:0.5-0.9). CONCLUSION: Before the COVID-19 pandemic, most people with colon or rectal cancer received treatment ≤2 months post-diagnosis, however, treatment patterns varied by spread of disease and age. This work can be used to inform future healthcare requirements, to estimate the impact of cancer control interventions to improve prevention and early diagnosis, and serve as a benchmark to assess treatment delays/disruptions during the pandemic. Future work should examine associations with clinical factors (e.g. performance status at diagnosis) and interdependencies between characteristics such as age, comorbidities, and emergency department visits.

Temporal trends in age- and stage-specific incidence of colorectal adenocarcinomas in Germany.

BACKGROUND: A national colorectal cancer (CRC) screening programme was launched in 2002 in Germany. A comprehensive evaluation of the programme effectiveness using real-world data is still lacking. In addition, there are regional reports on increasing colorectal cancer incidence in younger populations. Therefore, we aimed to describe and compare the overall, age- and stage-specific incidence trends for colorectal, colon and rectal cancer. METHODS: We used data from seven population-based cancer registries in Germany. We report absolute and relative changes in incidence rates between the early screening phase (2003-2005) and the most recent time period available (2015-2017), as well as annual percent changes. We analysed incidences according to tumour site (colorectum, colon, and rectum) and to six age groups (young adults: 15-34, 35-39, 40-49, screening-entitled/older adults: 50-54, 55-69 and 70 + years old). RESULTS: In our sample of 271,011 colorectal adenocarcinomas, about two-thirds were located in the colon and 95% of them occurred in the age group 50+ (50-54: 5%, 55-69: 32.8%, 70+: 57.2%). For the time period 2003-2005 the age-specific incidence rates of individuals in the age group 55-69 were about 76/100,00 for colon and 54/100,000 for rectal cancer (age group 70 + colon: 179/100,000; rectum: 84/100,000). The incidence rates in young adults were less than 13% of that of individuals in the age group 55-69 (< 5% of individuals aged 70+; <33% of individuals aged 50-54). Over time, incidence decreased in individuals at the age of 55+, for all subsites considered as well as for early and late stage cancers (with few exceptions), while incidence of young adult CRC (both early and late stage) increased steepest in the youngest age groups. For late stage rectal cancer, a shift was observed in all age groups from UICC stage IV to stage III being the most frequent stage. CONCLUSIONS: Six years after the introduction of the national colonoscopy screening program, late stage CRC incidence began to decline substantially in the screening-eligible age groups (55-69, 70+). It is likely that this decline and the increase in early stage CRC observed in younger age groups can be attributed to the program. Long lasting public awareness campaigns for CRC screening might have led to opportunistic screening in younger adults. Whether these benefits outweigh the possible harm of screening in younger age groups remains unclear.

Increased Burden of Second Bladder Cancer and Rectal Cancer in Prostate Cancer Treated With Radiotherapy: Results From Surveillance, Epidemiology, and End Results.

BACKGROUND: Previous studies have confirmed the higher risk of bladder cancer (BC) and rectal cancer (RC) development among prostate cancer (PCa) patients receiving radiotherapy. In this study, we intend to explore the long-term trend in second BC and RC incidence among PCa patients undergoing radiotherapy. METHOD: We identified first primary PCa patients diagnosed between 1975 and 2014 from the Surveillance, Epidemiology, and End Results (SEER)-9 cancer registries. Standardized incidence ratios (SIRs) were calculated by calendar year of diagnosis among PCa patients receiving radiotherapy and not. P trends were evaluated using Poisson regression. 10-year cumulative incidence of BC and RC was calculated utilizing competing risk regression model. RESULT: Of PCa patients treated with radiotherapy, SIRs of BC increased from .82 (95% CI: .35- 1.61) in 1980-1984 to 1.58 (95% CI: 1.48-1.68) in 2010-2014 (Ptrend=.003). SIRs of RC increased from 1.01 (95% CI: .27-2.58) in 1980-1984 to 1.54 (95% CI: 1.31-1.81) in 2010-2014 (Ptrend=.025). No statistically significant change in both BC and RC incidence was observed. The 10-year cumulative incidence of BC increased from 1975-1984 (.04%) to 2005-2014 (.15%) among PCa treated with radiotherapy. Simultaneously, the 10-year cumulative incidence of RC was demonstrated to range from 1975-1984 (.02%) to 2005-2014 (.11%). CONCLUSION: we have observed an increasing trend in second BC and RC incidence in PCa patients receiving radiotherapy. There was no significant change in the incidence of second BC and RC in PCa without radiotherapy. These results reflect the increasing clinical burden of second malignant tumors in PCa patients undergoing radiotherapy.

Management of the Rectal Stump after Subtotal Colectomy Operations for Inflammatory Bowel Disease in the Era of Immunologic Therapy: A Two-Centre Cohort Study.

INTRODUCTION: Inflammatory bowel disease (IBD) often requires surgical resection, such as subtotal colectomy operations to alleviate symptoms. However, IBD also has an inherently increased risk of colorectal dysplasia and cancer. Despite the well-accepted surveillance guidelines for IBD patients with an intact colon, contemporaneous decision-making models on rectal stump surveillance is sparse. This study looks at the fate of rectal stumps in IBD patients following subtotal colectomy. METHODS: This is a two-centre retrospective observational cohort study. Patients were identified from NHS Grampian and NHS Highland surgical IBD databases. Patients that had subtotal colectomy between January 01, 2010 and December 31, 2017 were included with the follow-up end date on April 1, 2021. Socio-demographics, diagnosis, medical and surgical management data were collected from electronic records. RESULTS: Of 250 patients who had subtotal colectomy procedures, only one developed a cancer in their rectal stump (0.4%) over a median follow-up of 80 months. A higher than expected 72% of patients had ongoing symptoms from their rectal stumps. Surveillance was varied and inconsistent. However, no surveillance, flexible sigmoidoscopy, or MRI identified dysplastic or neoplastic disease. CONCLUSION: Based on our results, we estimate that the prevalence of rectal cancer is lower than previously reported. Surveillance strategy of rectal stump varied as no current guidelines exist and hence is an important area for future study. Given the relatively low frequency of rectal cancer in these patients, and the low level of evidence available in this field, we would propose a registry-based approach to answering this important clinical question.

Risk and survival in colorectal cancer with increasing body mass index: A nationwide population-based cohort study.

AIM: The aim was to explore potential associations between the body mass index (BMI) and the risk of colorectal cancer (CRC), including subsites of the colon, and cancer-specific death. METHODS: A registry-based cohort study was conducted with baseline data gathered from the Norwegian Tuberculosis Screening Programme, collected between 1963 and 1975, and linked to follow-up data from the Cancer Registry of Norway and the Norwegian Cause of Death Registry. Cox regression models were used to explore associations between BMI and CRC risk and cancer-specific death. RESULTS: Of 1 723 692 included individuals, 76 616 developed CRC during 55 370 707 person-years of follow-up. In men, a 5 kg/m2 increase in BMI was associated with an increased risk of colon cancer, including both right and left subsites, and rectal cancer. Allowing for nonlinearities, we found a U-shaped association for the right colon and an inverse U-shape for the left colon and rectum cancer. In women, a 5 kg/m2 increase in BMI in early adulthood was associated with increased risk of colon cancer, including both subsites. In women, an increased risk of CRC death with increasing BMI was found for colon cancer. CONCLUSIONS: Men of all ages have an increased risk of CRC with increasing BMI, with the highest risk for right-sided colon cancer. An increased risk for colon cancer was also found in women with high BMI in early adulthood. Furthermore, women of all age groups appeared to have an increased risk of CRC death with higher BMI.

Clinicopathological characteristics of rectal multiple neuroendocrine neoplasms and literature review.

BACKGROUND: There are only a few epidemiological reports available for reference. The clinicopathological features are not clear, so there is no consensus on treating rectal multiple neuroendocrine neoplasms. This study aims to summarize the clinicopathological characteristics and preliminarily discuss the clinical diagnosis and treatment of rectal multiple neuroendocrine neoplasms. METHODS: This study retrospectively analyzed rectal neuroendocrine neoplasm patients diagnosed and treated at the Fourth Hospital of Hebei Medical University from February 2007 to May 2021. The clinicopathological characteristics of rectal multiple neuroendocrine neoplasms were summarized and analyzed in combination with 14 studies on rectal multiple neuroendocrine neoplasms. RESULTS: The incidence of RM-NENs accounted for 3.8% of all R-NENs in this study. The number of tumors varied to some extent, the size of tumors was basically no more than 10 mm, and there were more G1 grade tumors. In the analysis of 46 cases with known lymph node metastasis, the difference in lymph node metastasis rate between the number of tumors < 8 and ≥ 8 was statistically significant (p = 0.002). CONCLUSIONS: The incidence of rectal multiple neuroendocrine neoplasms accounted for 3.8% of all rectal neuroendocrine neoplasms. For rectal multiple neuroendocrine neoplasms, the lymph node metastasis rate was higher when the number of tumors was ≥ 8. The influence of the number of tumors on lymph node metastasis should be considered in the selection of treatment.

The incidence of malignancy in the residual rectum of IBD patients after colectomy: a systematic review and meta-analysis.

BACKGROUND: Patients with inflammatory bowel disease (IBD) who have had a total colectomy remain with their rectum in situ, and are therefore at risk of rectal carcinoma. It is not clear how high the incidence of rectal cancer is in this cohort. The primary objective of this meta-analysis was to estimate the incidence of rectal cancer in patients with ulcerative colitis or Crohn's disease who have undergone colectomy but have a residual rectum, and to identify the risk factors for its development. In doing so, we explore the current recommendations for screening processes for these patients. METHODS: A systematic review of the literature was performed. Five databases (Medline, Embase, Pubmed, Cochrane Library and Scopus) were searched from inception to 29 October 2021, to identify studies adhering to the population, intervention, control and outcomes (PICO) criteria. The included studies were critically appraised, and the relevant data was extracted. Cancer incidence was estimated from the reported information. Risk stratification was analysed using RevMan. A narrative approach was undertaken for the exploration of the existing screening guidelines. RESULTS: Data from 23 of the 24 identified studies was suitable for analysis. The pooled incidence of rectal carcinoma was calculated to be 1.3%. Subgroup analysis showed an incidence of 0.7% and 3.2% for patients with a de-functioned rectal stump and ileorectal anastomosis, respectively. Patients with a history of a colorectal carcinoma were more likely to have a subsequent diagnosis of rectal carcinoma (RR 7.2, 95% CI 2.4-21.1). Patients with previous colorectal dysplasia were also at higher risk (RR 5.1, 95% CI 3.1-8.2). No universal standardised guidance regarding screening for this cohort could be identified in the available literature. CONCLUSIONS: The overall risk of malignancy was estimated to be 1.3%, which is lower than previously reported. There is a need for clear and standardised screening guidance for this group of patients.

Radiation Therapy Changed the Second Malignancy Pattern in Rectal Cancer Survivors.

Background and Objectives: Radiotherapy (RT) plays an important role in the treatment for locally advanced rectal cancer patients. It can bring radio exposure together with the survival benefit. Cancer survivors are generally at an increased risk for second malignancies, and survivors receiving RT may have higher risks than survivors not receiving RT. Whether the risk of an all-site second malignancy may increase after RT is still debated. This study aims to compare the second malignancy pattern in rectal cancer survivors after RT. Materials and Methods: The Surveillance, Epidemiology, and End Results (SEER) database was used for analysis. In total, 49,961 rectal cancer patients (20-84 years of age) were identified between 2000 and 2012 from 18 SEER registries. All patients underwent surgery. The occurrence of second malignancies diagnosed after rectal cancer diagnosis was compared in patients who received and did not receive RT. The standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) were used. SEER*Stat was used to generate the 95% CIs for the SIR statistics using the exact method. Results: Of the total 49,961 patients, 5582 developed second malignancies. For all-site second primary malignancies, the age-adjusted SIRs were 1.14 (95% CI 1.1-1.18) and 1.00 (95% CI 0.96-1.04) in the no RT and RT groups, respectively. In 23,192 patients from the surgery-only group, 2604 had second malignancies, and in 26,769 patients who received RT, 2978 developed second malignancies. With respect to every site, the risk of secondary prostate cancer was significantly lower in the RT group (SIR = 0.39, 95% CI 0.33-0.46) than that in the surgery-only group (SIR = 1.04, 95% CI 0.96-1.12). Moreover, the risk of thyroid cancer was significantly higher in the RT group (SIR = 2.80, 95% CI 2.2-3.51) than that in the surgery-only group (SIR = 1.29, 95% CI 0.99-1.66). Conclusions: RT may change the second malignancy pattern in rectal cancer survivors; the risk of prostate cancer decreased, and the risk of thyroid cancer increased most significantly.

Energy balance-related factors in childhood and adolescence and risk of colorectal cancer based on KRAS, PIK3CA, and BRAF mutations and MMR status.

KRAS mutations (KRASmut ), PIK3CAmut , BRAFmut , and deficient DNA mismatch repair (dMMR) have been associated with the Warburg effect. We previously reported differential associations between early-life energy balance-related factors (height, energy restriction, body mass index [BMI]) and colorectal cancer (CRC) subtypes based on the Warburg effect. We now investigated associations of early-life energy balance-related factors and the risk of CRC subgroups based on mutation and MMR status. Data from the Netherlands Cohort Study was used. KRASmut , PIK3CAmut, BRAFmut, and MMR status were available for 2349 CRC cases, and complete covariate data for 1934 cases and 3911 subcohort members. Multivariable-adjusted Cox regression was used to estimate associations of height, energy restriction proxies (exposure to Dutch Hunger Winter, Second World War, Economic Depression), and early adult BMI (age 20 years) with risk of CRC based on individual molecular features and combinations thereof (all-wild-type+MMR-proficient [pMMR]; any-mutation/dMMR). Height was positively associated with any-mutation/dMMR CRC but not all-wild-type+pMMR CRC, with the exception of rectal cancer in men, and with heterogeneity in associations observed for colon cancer in men (p-heterogeneity = 0.049) and rectal cancer in women (p-heterogeneity = 0.014). Results on early-life energy restriction proxies in relation to the risk of CRC subgroups did not show clear patterns. Early adult BMI was positively, but not significantly, associated with KRASmut colon cancer in men and with BRAFmut and dMMR colon cancer in women. Our results suggest a role of KRASmut , PIK3CAmut , BRAFmut , and dMMR in the etiological pathway between height and CRC risk. KRASmut might potentially play a role in associations of early adult BMI with colon cancer risk in men, and BRAFmut and dMMR in women.

Diagnosis and Management of Rectal Cancer in Patients Younger Than 50 Years: Rising Global Incidence and Unique Challenges.

The global incidence of colorectal adenocarcinoma is stable or decreasing overall; however, the incidence of colorectal cancer in patients aged <50 years is increasing. Although some of this increase is due to hereditary cancer syndromes, this is not the sole explanation. Patients with early-onset rectal cancer in particular have unique disease patterns and face distinct challenges in their treatment. Molecular patterns of disease in this patient cohort are noteworthy and often represent an opportunity to target these cancers more effectively. Recent and ongoing trials focusing on minimizing toxicities and necessary therapy modalities and maximizing response and patient outcome are of paramount importance in this patient population. Additional resources are needed for this patient population, including fertility counseling and preservation, financial guidance, genetic counseling, and psychosocial support.

Characteristics of primary signet ring cell carcinoma of colon and rectum: a case control study.

BACKGROUND: Primary signet ring cell carcinoma of the colon and rectum (PSRCCR) is rare, usually diagnosed at advanced stage with poor outcomes. We aimed to find possible diagnostic clues in order to help diagnosis. METHODS: A retrospective study of PSRCCR patients from 1993 to 2018 was reviewed at a single tertiary center. Colorectal adenocarcinoma patients as control group with 1:4 ratio was also enrolled. RESULTS: 18 patients with PSRCCR were identified. The prevalence rate was 0.16% (18 of 11,515). The mean age was 50.2 years-old in PSRCCR group and 63 years-old in non-SRCC colorectal cancer patients (p < 0.001). Diagnosis tool depends on colonoscopy were much less in PSRCCR group than control group (44.4% vs 93%, p < 0.001). SRCC patients had higher level of CEA (68.3 vs 17.7 ng/mL, p = 0.004) and lower level of Albumin (3.4 vs 4.3 g/dL, p < 0.001). The majority of PSRCCR tumor configuration was ulcerative and infiltrative. More PSRCCR pathology presented as high-grade carcinoma (66.7 vs 1.4%, p < 0.001) and lymphovascular invasion (77.8 vs 44.4%, p = 0.011) than control group. More PSRCCR patients were diagnosed at advanced stage (88.8 vs 40.3%, p = 0.001). Higher mortality was also noticed in PSRCCR group than control group (72.2 vs 20.8%, p < 0.001). CONCLUSION: For young patients with long segment colonic stenosis and ulcerative/ infiltrative mucosa but endoscopic biopsy failed to identify malignant cells, earlier operation or non-colon site biopsy is suggested for diagnosing the PSRCCR.

Rectal Neuroendocrine Neoplasms: Why Is There a Global Variation?

PURPOSE OF REVIEW: This review examines the variation in incidence of rectal neuroendocrine tumours across the globe. Rectal neuroendocrine tumours are a common type of gastrointestinal NET with an increasing incidence reported over the last 30 years. RECENT FINDINGS: There have been a number of publications examining the epidemiology of neuroendocrine tumours across the world. These have utilized a variety of different methodologies to examine both incidence of prevalence of NETs. We review the data published and describe any causative factors and findings regarding the epidemiology of rectal NETs. Rectal NETs account for 1-2% of all rectal cancers and are commonly diagnosed between 50-60 years of age. Most lesions are identified by chance at colonoscopy, commonly during colon cancer screening procedures, which is reflected in part in the age at diagnosis. Most lesions are small in size, < 10 mm and can be managed with endoscopic resection rather than requiring surgery. The highest incidence is reported in people of Asian ethnicity, with a tenfold increased incidence reported in some series compared with white population. There is also an increased incidence in Black and Hispanic population as identified through the Surveillance, Epidemiology and End Results (SEER) database. Endoscopic assessment of lesions is variable globally. Future work to better understand the cause of ethnic variation and development of comprehensive cancer registries would be helpful.

Limited impact of the COVID-19 pandemic on colorectal cancer care in the Netherlands in 2020.

PURPOSE: The COVID-19 pandemic had a major impact on the health services worldwide. We aimed to investigate the impact of the pandemic on colorectal cancer (CRC) care in the Netherlands in 2020. METHODS: CRC patients, diagnosed in 2018-2020 in the Netherlands, were selected from the Netherlands Cancer Registry (NCR). The year 2020 was divided in four periods reflecting COVID-19 developments in the Netherlands (pre-COVID, 1st peak, recovery period, 2nd peak) and compared with the same periods in 2018/2019. Patient characteristics and treatment were compared using the Chi-squared test. Median time between diagnosis and treatment, and between (neo)adjuvant therapy and surgery were analyzed by the Mann-Whitney U test. RESULTS: In total, 38,021 CRC patients were diagnosed in 2018/2019 (n = 26,816) and 2020 (n = 11,205). Median time between diagnosis and initial treatment decreased on average 4 days and median time between neoadjuvant radiotherapy and surgery in clinical stage II or III rectal cancer patients increased on average 34 days during the three COVID-19 periods compared to the same periods of 2018/2019. The proportion of colon cancer patients that underwent elective surgery significantly decreased with 3.0% during the 1st peak. No differences were found in the proportion of patients who received (neo)adjuvant therapy, systemic therapy, or no anti-cancer treatment. CONCLUSION: Only minor changes in the care for CRC patients occurred during the COVID-19 pandemic, mostly during the 1st peak. In conclusion, the impact on CRC care in the Netherlands was found to be limited. However, long-term effects cannot be precluded.

Association of sedentary work with colon and rectal cancer: systematic review and meta-analysis.

OBJECTIVES: There has been no research on sedentary behaviour in the occupational domain that occupies a large portion of the daily life. METHODS: We conducted a meta-analysis to investigate the association between sedentary work and colorectal cancer. We searched PubMed, Embase and Cochrane databases up to 12 August 2020 for peer-reviewed journal articles that assessed the association between sedentary work and colon or rectal cancer. Pooled estimates of ORs were obtained using random effects models. Statistical tests for publication bias, heterogeneity and sensitivity analysis were applied. RESULTS: Of the 5 381 studies initially identified, 23 studies with 64 reports were eligible for inclusion. Sedentary work significantly increased the risk of colon cancer (pooled OR=1.21, 95% CI 1.11 to 1.31, p value ≤0.0001) and rectal cancer (pooled OR=1.08, 95% CI 1.00 to 1.16, p value=0.0395). The adjustment for leisure time physical activity attenuated the association and made the risk estimates non-significant for sedentary behaviour, but the association was independent of sex, control of body mass index and assessment of sedentary behaviour. CONCLUSIONS: We found evidence of association between sedentary work and the risk of colon or rectal cancer. Limiting excessive sedentary work could be an important means of preventing colon and rectal cancer.

Ileo-rectal anastomosis in ulcerative colitis-Long-term outcome, failure and risk of cancer at a tertiary centre.

AIM: Ileo-rectal anastomosis (IRA) is an option to restore bowel continuity after colectomy in patients with ulcerative colitis (UC). Concerns that the remaining rectum may serve as a site for continuing proctitis with subsequent poor function and IRA failure and the fear of development of dysplasia and cancer have led to the abandonment of IRA in large parts of the world. This study investigated the outcome of IRA in a large patient cohort with UC and IRA with regard to failure of IRA and development of dysplasia and cancer. METHODS: This was a retrospective data gathering of patients with UC and IRA enrolled at the Department of Colorectal Surgery, Surgical Clinic, Sahlgrenska University Hospital/Östra, Gothenburg, 1972-2019. End-points were IRA failure, rectal dysplasia and cancer. IRA survival analysis and the cumulative probability of rectal cancer were calculated. RESULTS: In total, 183 patients (121 men) were included in the study. The IRA failure rate was 34% and the estimated cumulative IRA failure rates were 25% and 35% at 5 and 10 years respectively. Four patients developed rectal cancer and the estimated cumulative probability of rectal cancer was 3% and 6% at 10 and 15 years respectively. CONCLUSION: Ileo-rectal anastomosis remains a restorative option after colectomy for UC, even if the failure rate raises some concern. Further knowledge is needed for optimal patient selection to avoid early IRA failures. With increasing probability of rectal cancer over time a vigilant surveillance protocol is mandatory.

Contributions of Adenocarcinoma and Carcinoid Tumors to Early-Onset Colorectal Cancer Incidence Rates in the United States.

BACKGROUND: Early-onset colorectal cancer (EOCRC) incidence rates (IRs) are rising, according to previous cancer registry analyses. However, analysis of histologic subtypes, including adenocarcinoma (the focus of CRC screening and diagnostic testing) and carcinoid tumors (which are classified as "colorectal cancer" in SEER [Surveillance, Epidemiology, and End Results] databases but have a distinct pathogenesis and are managed differently from adenocarcinoma), has not been reported. OBJECTIVE: To assess EOCRC IRs and changes in IRs over time, stratified by histology. DESIGN: Retrospective analysis. SETTING: Yearly IRs according to SEER 18 data from 2000 to 2016 on age-specific colon-only, rectal-only, and combined-site CRC cases, stratified by histology ("overall" CRC [all histologic subtypes], adenocarcinoma, and carcinoid tumors) and age. PATIENTS: 119 624 patients with CRC. MEASUREMENTS: IRs per 100 000 population, changes in 3-year average annual IRs (pooled IRs from 2000 to 2002 vs. those from 2014 to 2016), and annual percentage change (APC) in persons aged 20 to 29, 30 to 39, 40 to 49, and 50 to 54 years. RESULTS: The steepest changes in adenocarcinoma 3-year average annual IRs were for rectal-only cases in persons aged 20 to 29 years (+39% [0.33 to 0.46 per 100 000]; P < 0.050) and 30 to 39 years (+39% [1.92 to 2.66 per 100 000]; P < 0.050) and colon-only cases in those aged 30 to 39 years (+20% [3.30 to 3.97 per 100 000]; P < 0.050). Corresponding APCs were 1.6% (P < 0.050), 2.2% (P < 0.050), and 1.2% (P < 0.050), respectively. In persons aged 40 to 49 years, 3-year average annual IRs increased in both colon-only (+13% [12.21 to 13.85 per 100 000]; P < 0.050) and rectal-only (+16% [7.50 to 8.72 per 100 000]; P < 0.050) subsites. Carcinoid tumors were common, representing approximately 4% to 20% of all colorectal and 8% to 34% of all rectal cancer cases, depending on age group and calendar year. Colon-only carcinoid tumors were rare. Colorectal carcinoid tumor IRs increased more steeply than adenocarcinoma in all age groups, thus affecting the contribution of carcinoid tumors to overall cancer cases over time. These changes were driven by rectal subsites and were most pronounced in persons aged 50 to 54 years, in whom rectal carcinoid tumors increased by 159% (2.36 to 6.10 per 100 000) between 2000 to 2002 and 2014 to 2016, compared with 10% for adenocarcinoma (18.07 to 19.84 per 100 000), ultimately accounting for 22.6% of all rectal cancer cases. LIMITATION: Population-based data. CONCLUSION: These findings underscore the importance of assessing histologic CRC subtypes independently. Doing so may lead to a better understanding of the drivers of temporal changes in overall CRC incidence and a more accurate measurement of outcomes from efforts to reduce adenocarcinoma risk, and can guide future research. PRIMARY FUNDING SOURCE: None.

Cancer of the Rectum and Rectosigmoid Junction: 20-Year Comparative Survival and Mortality Analysis by Age, Sex, Race, Stage, Grade, Cohort Entry Time-Period and Disease Duration: A Systematic Review of 266,898 Cases for Diagnosis Years 1973-2014: (SEER*Stat 8.3.4).

This article reviews a 20-year retrospective population-based study using the statistical database of SEER*Stat 8.3.4 to compare the occurrence, long-term survival and mortality indices of 266,898 patients with cancer of the rectum and rectosigmoid junction (RSJ) juxtaposed by age, sex, race, stage, grade, disease duration, in two cohort entry time-periods, 1973-1994 & 1995-2014.