High Probability of an Underlying Colorectal Cancer Among Patients Treated for Acute Diverticulitis. A Population-Based Cohort Follow-Up Study

Diverticulitis Is Associated with Increased Risk of Colon Cancer-A Nationwide Register-Based Cohort Study

Background: An association between diverticulitis and colon cancer has been proposed. The evidence is conflicting, and the guidelines differ regarding recommended follow-up with colonoscopy after an episode of diverticulitis. To guide regimes for follow-up, this study aimed to investigate if patients with diverticulitis have an increased risk of colon cancer. Methods: This study is reported according to the RECORD statement. We performed a cohort study with linked data from nationwide Danish registers. The inclusion period was 1997-2009, and the complete study period was 1995-2013. The primary outcome was the risk of developing colon cancer estimated using a Cox regression analysis with time-varying covariates. We performed a sensitivity analysis on a cohort of people with prior colonoscopies, comparing the risk of colon cancer between the diverticulitis group and the control group. Results: We included 29,173 adult males and females with diverticulitis and 145,865 controls matched for sex and age. The incidence proportion of colon cancer was 2.1% (95% confidence interval (CI) 1.9-2.3) in the diverticulitis group and 1.5% (95% CI 1.4-1.5) in the matched control group (hazard ratio 1.6; 95% CI 1.5-1.8). The risk of having a colon cancer diagnosis was significantly increased in the first six months after inclusion (hazard ratio 1.7; 95% CI 1.5-1.8), and hereafter there was a lower risk in the diverticulitis group compared with controls (hazard ratio 0.8; 95% CI 0.7-0.9). This protective effect lasted eight years. The increased risk of colon cancer during the first six months after diverticulitis was also found in the cohort with prior colonoscopies. Conclusions: The risk of a colon cancer diagnosis was significantly increased for patients with diverticulitis 0-6 months after the diagnosis of diverticulitis. Hereafter, we found a protective effect of diverticulitis until eight years later, possibly due to a screening effect. We recommend a follow-up colonoscopy after the first diagnosis of diverticulitis.

Development and Validation of a Deep Learning Algorithm to Differentiate Colon Carcinoma From Acute Diverticulitis in Computed Tomography Images

IMPORTANCE

Differentiating between malignant and benign etiology in large-bowel wall thickening on computed tomography (CT) images can be a challenging task. Artificial intelligence (AI) support systems can improve the diagnostic accuracy of radiologists, as shown for a variety of imaging tasks. Improvements in diagnostic performance, in particular the reduction of false-negative findings, may be useful in patient care.

OBJECTIVE

To develop and evaluate a deep learning algorithm able to differentiate colon carcinoma (CC) and acute diverticulitis (AD) on CT images and analyze the impact of the AI-support system in a reader study.

DESIGN, SETTING, AND PARTICIPANTS

In this diagnostic study, patients who underwent surgery between July 1, 2005, and October 1, 2020, for CC or AD were included. Three-dimensional (3-D) bounding boxes including the diseased bowel segment and surrounding mesentery were manually delineated and used to develop a 3-D convolutional neural network (CNN). A reader study with 10 observers of different experience levels was conducted. Readers were asked to classify the testing cohort under reading room conditions, first without and then with algorithmic support.

MAIN OUTCOMES AND MEASURES

To evaluate the diagnostic performance, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for all readers and reader groups with and without AI support. Metrics were compared using the McNemar test and relative and absolute predictive value comparisons.

RESULTS

A total of 585 patients (AD: n = 267, CC: n = 318; mean [SD] age, 63.2 [13.4] years; 341 men [58.3%]) were included. The 3-D CNN reached a sensitivity of 83.3% (95% CI, 70.0%-96.6%) and specificity of 86.6% (95% CI, 74.5%-98.8%) for the test set, compared with the mean reader sensitivity of 77.6% (95% CI, 72.9%-82.3%) and specificity of 81.6% (95% CI, 77.2%-86.1%). The combined group of readers improved significantly with AI support from a sensitivity of 77.6% to 85.6% (95% CI, 81.3%-89.3%; P < .001) and a specificity of 81.6% to 91.3% (95% CI, 88.1%-94.5%; P < .001). Artificial intelligence support significantly reduced the number of false-negative and false-positive findings (NPV from 78.5% to 86.4% and PPV from 80.9% to 90.8%; P < .001).

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that a deep learning model able to distinguish CC and AD in CT images as a support system may significantly improve the diagnostic performance of radiologists, which may improve patient care.

Diverticulitis does not increase the long-term risk of developing colon cancer: a systematic review and meta-analysis

PURPOSE

The aim of this review was to examine if diverticulitis increases the long-term risk (> 6 months) of developing colon cancer.

METHODS

A systematic search was conducted in PubMed, Embase, and Cochrane CENTRAL. Google Scholar was also searched. We included studies with human adults of 18 years of age and above. Studies that included only patients with diverticulitis as well as studies comparing groups with and without diverticulitis were included. The primary outcome was the incidence of colon cancer 6 months or more after an episode of diverticulitis.

RESULTS

Twelve records were included with 38,621 patients with diverticulitis. The crude rate of colon cancer among the prospectively followed populations with diverticulitis was by meta-analysis found to be 0.6% (95% CI 0.5-0.6%). The limitations of this review include heterogeneous reporting of outcomes across studies, specifically regarding population and outcome as well as variations in the design and reporting of the studies.

CONCLUSION

We found that the long-term risk of colon cancer after diverticulitis is not increased. The results of our review support current practice on follow-up after an episode of diverticulitis with short-term follow-up being the primary focus.

Epidemiology of Diverticulitis and Prevalence of First-Ever Colorectal Cancer Postdiverticulitis in Adults in the United States: A Population-Based National Study

BACKGROUND

The incidence of acute diverticulitis is increasing, and previous studies showed a wide range of prevalence of colorectal cancer after diverticulitis. There is a lack of high-quality evidence to support performing colonoscopy after diverticulitis.

OBJECTIVE

We aimed to describe the incidence of first-ever diverticulitis and prevalence of first-ever colorectal cancer postdiverticulitis in the United States.

DESIGN

This is a retrospective cohort study.

SETTINGS

We queried a national database that contains data from 26 major integrated healthcare systems in the United States.

PATIENTS

We identified an aggregated patient cohort aged ≥18 years with a diagnosis of first-ever diverticulitis from February 2015 to February 2020, followed by first-ever colorectal cancer diagnosis, at least 1 day after and within 1 year of diverticulitis.

MAIN OUTCOME MEASURES

The incidence of first-ever diverticulitis was calculated. The prevalence and OR of first-ever colorectal cancer after diverticulitis were analyzed.

RESULTS

Among 31,778,290 individuals, we found the incidence of first-ever acute diverticulitis to be 2.9%. The prevalence of colorectal cancer within 1 year of first-ever acute diverticulitis was 0.57%, whereas the prevalence of colorectal cancer without a history of diverticulitis was 0.31% (OR = 1.8 (95% CI, 1.76-1.86)). The majority (92.3%) of the postdiverticulitis colorectal cancer were diagnosed within the first 6 months. The risk of colorectal cancer postdiverticulitis was higher in women (OR = 1.9), African Americans (OR = 2.0), and adults aged 18 to 65 years (OR = 2.3).

LIMITATIONS

We are unable to validate the diagnostic code because patient information in our database is deidentified.

CONCLUSIONS

Individuals are twice as likely to be diagnosed with colorectal cancer within 1 year of their first episode of acute diverticulitis compared with individuals without diverticulitis. We advocate for colonoscopy after the first occurrence of acute diverticulitis to screen for colorectal cancer, particularly for patients without a recent colonoscopy. See Video Abstract at http://links.lww.com/DCR/B412.

Interval colonoscopy following acute diverticulitis should not be discouraged yet: results from a retrospective cohort

BACKGROUND

Although included in some guidelines, the recommendation of interval colonoscopy after an acute diverticulitis (AD) episode has recently been questioned. In this study, we evaluated the incidence of colon cancer during the follow-up of an episode of AD.

METHODS

A retrospective review was carried out of patients with conservatively treated AD at our Institution (January 2011 to December 2018) with or without endoscopic study. Patients who had no colonoscopy performed were followed for two years. The demographic, clinical, radiological, follow-up and anatomopathological records were analysed. We determined CT scan validity for the differential diagnosis of CC and AD; sensibility, specificity, predictive values and likelihood ratios were calculated. Patients lost to follow-up and patients who had had colonoscopy in the previous three years were excluded.

RESULTS

This study included 285 patients with a mean age of 59 years. A total of 225 interval colonoscopies were performed and 60 patients without colonoscopy were followed up. There were 19 CC (6.7%) diagnosed, 14 with interval colonoscopy and 5 during follow-up; 8 (42.1%) happened in patients who had had an episode of uncomplicated AD. Although CT scan accuracy is high, 87.7%, positive and negative likelihood ratios were low, 4.67 and 0.64, respectively.

CONCLUSIONS

Interval colonoscopy should still be advisable after an episode of AD. The rationale for this statement is based on a non-negligible rate of hidden CC and an important uncertainty in the differential diagnosis.

Computed tomography diagnosed first time diverticulitis and colorectal cancer

BACKGROUND

Computed tomography (CT) with intravenous contrast is the gold standard for diagnosing diverticulitis. Published results concerning follow-up colonoscopy after an episode of acute diverticulitis to rule out cancer are conflicting. This study aimed to evaluate the risk of underlying colonic malignancy in patients diagnosed with a first time diverticulitis with a state of the art CT investigation with intravenous contrast.

METHODS

Retrospective analysis of all patients with a first episode of diverticulitis diagnosed with CT at Danderyds Hospital, Stockholm, between January 1, 2015, and November 16, 2016. Data on modified Hinchey classification, age, sex, laboratory parameters, body mass index, and colonoscopy findings were recorded.

RESULTS

The study identified 518 patients with a CT-verified first time diverticulitis. Four hundred twenty-six (82%) of the 518 patients underwent follow-up colonoscopy and constitute our study cohort. CT showed that 402 patients had uncomplicated diverticulitis (modified Hinchey Ia), and 24 patients had complicated diverticulitis (modified Hinchey ≥Ib). Colonoscopy showed cancers in 2 (0.5%) of the 426 patients initially diagnosed as acute diverticulitis. In addition, 13 (3%) patients had advanced adenomas, and 121 (28%) patients had benign adenomas upon follow-up colonoscopy. Patients with CT-verified complicated diverticulitis (modified Hinchey ≥Ib) had a significantly higher risk for colon cancer compared with patients with an uncomplicated first time diverticulitis.

CONCLUSION

Our study supports routine follow-up colonoscopy after a first episode of CT-diagnosed complicated diverticulitis. In contrast, we do not find an increased risk for neoplasia in patients with uncomplicated diverticulitis.

Comment on: Should a colonoscopy be offered routinely to patients with CT proven acute diverticulitis? A retrospective cohort study and meta-analysis of best available evidence

Latest evidence indicates that patients with acute diverticulitis have higher prevalence of colorectal cancer than reference patients. Therefore, colonoscopy should be offered after an episode of acute diverticulitis.

Prevalence of colorectal cancer and advanced adenoma in patients with acute diverticulitis: implications for follow-up colonoscopy

BACKGROUND AND AIMS

Guidelines recommend colonoscopy after an episode of diverticulitis to exclude neoplasia but the effectiveness of testing is uncertain. Patients with complicated diverticulitis may be at higher risk for neoplasia, but most patients have uncomplicated disease. We examined the incidence of colorectal cancer (CRC) and advanced adenoma (AA) in patients with diverticulitis compared with patients undergoing screening colonoscopy.

METHODS

CT scans from January 1, 2008, to May 1, 2013, at the University of Pittsburgh Medical Center (UPMC) were reviewed to identify those with confirmed acute diverticulitis. Subsequent surgical, colonoscopy, and pathology reports were abstracted to identify those with a diagnosis of AA and CRC. The incidence of neoplasia was compared with that reported for screening colonoscopy from a meta-analysis (n = 68,324), and from colonoscopy examinations at UPMC between 2013 and 2015 (n = 28,573).

RESULTS

A total of 5167 abdominal/pelvic CT scan reports identified 978 patients with acute diverticulitis, among which 474 (48.5%) patients had undergone at least 1 colonoscopy or gastrointestinal surgery to April 2015. The CRC rate in patients with diverticulitis (13/474, 2.7%) was significantly higher (P < .0001) compared with both the meta-analysis (0.8%) and UPMC (0.3%). The AA rate (19/474, 4.0%) was similar to the rate in the meta-analysis (5.0%, P = .39) but significantly lower than at UPMC (7.7%, P = .003). The incidence of AA or CRC in complicated diverticulitis (10/141, 7.1%) did not differ significantly (P = .85) from the incidence of AA or CRC in uncomplicated diverticulitis (22/332, 6.6%).

CONCLUSIONS

CRC after diverticulitis was significantly higher than that observed at screening colonoscopy and was not limited to complicated disease. Colonoscopy is advisable after the diagnosis of diverticulitis.

Efficacy of colonoscopy after an episode of acute diverticulitis and risk of colorectal cancer

Background

Diverticular disease of the colon has a high global prevalence. The guidelines suggest performing a colonoscopy 4-6 weeks after the acute episode to exclude colorectal cancer (CRC). However, these recommendations are based on old studies, when computed tomography was not used to diagnose acute diverticulitis (AD). There are currently some studies showing that CRC incidence is low in uncomplicated AD (UAD). Therefore, we decided to perform this study to determine the CRC incidence after an AD episode and the diagnostic efficacy of colonoscopy in these patients.

Method

This was a retrospective cohort study that included patients with AD between July 2016 and December 2017.

Results

One hundred seventy-four patients had AD. Of these, 46 patients were excluded and we analyzed 128 patients, 72 (56.3%) women and 56 (43.7%) men. Ninety (70.3%) had UAD and 38 (29.7%) complicated AD (CAD). The colonoscopy showed lesions in 18 (14.06%), 5 (3.9%) being CRC. The patients with CRC had shown CAD and were >70 years old (P=0.0001 and P=0.002 respectively).

Conclusions

Routine colonoscopy in patients with UAD appears not have many benefits as a diagnostic tool. However, it has a higher efficacy if the patients have CAD and are >70 years old.

Risk of Colorectal Cancer in Patients With Acute Diverticulitis: A Systematic Review and Meta-analysis of Observational Studies

BACKGROUND & AIMS

We performed a systematic review and meta-analysis to assess the prevalence of colorectal cancer in patients with acute diverticulitis.

METHODS

We searched MEDLINE from inception through November 2nd, 2017 for studies reporting the prevalence of colorectal cancer in patients with diverticulitis, identified based on the protocol CRD42017083272. This systematic review was conducted in accordance to the MOOSE guidelines. Pooled prevalence values were obtained by random effects models and robustness was tested by leave-one out sensitivity analyses. Heterogeneity was assessed using the Q-test and quantified based on I2 value. The critical appraisal of included studies was performed using the Newcastle-Ottawa scale.

RESULTS

Our final analysis included 31 studies, comprising 50,445 patients. The pooled prevalence of colorectal cancer was 1.9% (95% CI, 1.5%-2.3%). Patients with complicated diverticulitis had a significantly higher risk for colorectal cancer (prevalence, 7.9%; 95% CI, 3.9%-15.3%) than patients with uncomplicated diverticulitis (prevalence, 1.3%; 95% CI, 0.1%-2%), corresponding to a pooled prevalence ratio of 6.7 (95% CI, 2.5-18.3). Subgroup analyses did not find significant difference in prevalence when separately pooling studies according to ranking on the Newcastle-Ottawa scale, geographical location or length of follow-up. Meta-regression did not find any association between age and colorectal cancer. Among patients who underwent endoscopy, the pooled prevalence of polyps was 22.7% (95% CI, 19.6%-26.0%), of advanced adenomas was 4.4% (95% CI, 3.4%-5.8%), of adenomas was 14.2% (95% CI, 11.7%-17.1%), and of hyperplastic polyps was 9.2% (95% CI, 7.6%-11.2%).

CONCLUSION

In a meta-analysis of observational studies of patients with acute diverticulitis, we found the pooled prevalence of colorectal cancer to be 1.9%. The risk of colorectal cancer was significantly higher in patients with complicated diverticulitis than in patients with uncomplicated diverticulitis.

Risk of colorectal cancer in patients with diverticular disease

Colorectal cancer constitutes an important burden on the healthcare system. Screening at-risk populations to reduce colorectal cancer-related morbidity and mortality has become part of good clinical practice. However, recommendations regarding subgroups of patients with diverticular disease are subject to controversy.

Herein, we review the most recent literature regarding the prevalence of colorectal cancer in patients with diverticular disease, diverticulitis and uncomplicated diverticulitis.

The recent literature does not identify diverticular disease as a long-term risk factor for colorectal cancer. However, the risk of colorectal cancer is increased in the short-term period after hospitalization related to diverticular disease. According to a recent systematic review and meta-analysis, the prevalence of colorectal cancer is 1.6% in patients with acute diverticulitis who underwent colonoscopy. The risk of having colorectal cancer after an episode of acute diverticulitis is 44-fold higher than that of an age- and gender-adjusted reference population. Despite lower among patients with uncomplicated episode, the risk of colorectal cancer remains 40-fold higher in that subpopulation than that in the reference population.

To conclude, the recent literature describes an increased risk of colorectal cancer among patients with acute diverticulitis compared to the reference population. Colonoscopy is therefore recommended in patients with diverticulitis to exclude colorectal cancer.