Beyond the scope: diverticular disease and post-colonoscopy colorectal cancer

Colonoscopy is considered the gold standard for colorectal cancer (CRC) prevention. It decreases the risk of developing CRC through detection and removal of precancerous colorectal lesions, adenomas, and serrated polyps. Since the implementation of screening programs, the incidence and mortality rates of CRC have decreased [1]. However, post-colonoscopy colorectal cancer (PCCRC), which is defined as CRC diagnosed after a colonoscopy and the scheduled surveillance colonoscopy, occurs in a significant number of patients. Risk factors for PCCRC include poor performance quality of the endoscopist, presence of high risk polyps at the index colonoscopy, increased patient age, and comorbidities of the patient [2] [3].

“The results of this study provide important evidence for consideration of personalized surveillance strategies for individuals with diverticular disease, independently of presence of colorectal polyps.”

Generally, the association between diverticular disease (respectively diverticulitis) and CRC is inconsistently discussed in the literature and has been an ongoing debate for years. Numerous studies have indicated that diverticular disease may be a risk factor for PCCRC based on the assumption that colonoscopy in patients with diverticular disease is technically more challenging and the assessment of the bowel mucosa might be restricted [4] [5].

In this issue of Endoscopy, Troelsen et al. present data on the risk of PCCRC in patients with diverticular disease compared with patients without diverticular disease who underwent mostly diagnostic colonoscopies within the Danish National Health Service Program [6]. The cohort study included 56 642 patients with and 306 800 without diverticular disease. Within a 3-year period after the index colonoscopy, the proportion of patients with CRC that was considered to be PCCRC was 6.5% for patients without diverticular disease, 19% for patients with diverticular disease overall, and 22% for PCCRC located in the proximal colon of patients with diverticular disease [6].

This study addresses an important topic both economically and from a healthcare point of view as diverticular disease is a common condition in the Western world. Nevertheless, presence of diverticular disease is not considered in current guidelines for CRC screening, even though it might be aligned with increased risk of CRC. The results of this study provide important evidence for consideration of personalized surveillance strategies for individuals with diverticular disease, independently of presence of colorectal polyps.

The welcoming result of the present study is that PCCRC in patients with diverticular disease is rare, under 1%.

However, a couple of features deserve further consideration. Regrettably, the study lacks data on key performance quality measures (i.e. adenoma detection rate, bowel cleansing quality, cecal intubation rate) [7]. This is particularly relevant as one of the main findings is the slightly higher rate of proximal PCCRC. Proximally located polyps are often sessile serrated lesions, the detection of which are especially dependent on adequate bowel cleansing and high competence of the endoscopists. Moreover, as discussed by the authors, colonoscopy performed in individuals with diverticular disease is technically more challenging and hence one could assume that the cecal intubation rate in those individuals might be lower, which could be a possible explanation for higher rates of proximal PCCRC.

Another concern is the heterogeneity of the study cohort. This might bias the interpretation of the results. Patients with diverticular disease were older and had more comorbidities, which are factors associated with a higher risk of developing PCCRC (i.e. due to worse bowel preparation, technically more challenging endoscopies, and age being the strongest risk factor for the development of CRC).

The authors were also unable to clearly distinguish between diverticular disease and diverticulitis, which is important because inflammation, particularly recurrent or chronic inflammation, is discussed as playing a key role in malignant disease.

Finally, considering the results somehow challenge surveillance algorithms, the inclusion of individuals with hereditary cancer syndromes is debatable as they are recommended to follow specific surveillance algorithms.

In summary, colonoscopy is definitely one of the great success stories in cancer prevention. Nevertheless, it still has its obstacles, which must be discussed. There is very strong evidence on how to decrease the risk of PCCRC in terms of performance quality and surveillance based on colonoscopy findings. Data on patient-related factors are comparably scarce. Therefore, the present study adds valuable evidence for individualized screening and surveillance recommendations based on patient characteristics. To implement specific recommendations into clinical practice, randomized controlled trials are needed in the future.

Ultimately, the importance of structured colonoscopy reports must be stressed in order to provide and monitor quality parameters in colonoscopy, as a high quality colonoscopy is the most crucial factor in decreasing PCCRC. Based on the present and previous studies, the inclusion of information on presence of diverticular disease in the colonoscopy report seems worthy of debate.

Publication History

Article published online:
16 May 2024

• References

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