Complex colon cancer

Complex colon cancer

– The Tenth Dutch Snapshot study –


In the Netherlands, 7000 colonic resections for cancer are performed yearly, predominantly in non-academic centers. A subset of these tumors comprises high-complex stage II-III disease. Among these, obstructive colon cancer is an extensively studied entity.However, other complex colon cancers are strikingly less often addressed in literature, including those with isolated locoregional recurrence, infectious tumor-related complications (proximal blow-out, perforated tumor or peritumoral abscess) or with ingrowth into surrounding structures or organs (cT4b stage). Isolated locoregional recurrence develops in 4-13% of patients who have undergone curative resection for primary stage I-III colon cancer. Infectious tumor-related complications occur in 2-10%, and around 5% of the patients will present with cT4b stage. Surgery is generally performed at the hospital where the patient was initially diagnosed, with reported high morbidity and mortality rates, and worse survival compared to the remaining patients with stage II-III disease. Optimal treatment strategy of these colon cancers and the potential role for centralization remains largely unknown.


1. Determine the incidence of colon cancer with tumor-related infectious complications, asymptomatic cT4 stage and locoregional recurrence within a nationwide cohort of patients with stage I-III colon cancer treated in 2014/2015
2. Evaluate the diagnostic and decision-making process in colon cancer with tumor-perforation, proximal perforation, peritumoral abscess and asymptomatic cT4 stage.
3. To determine type of therapy with associated short and long-term surgical and oncological outcomes of colon cancer with tumor-perforation, proximal perforation, peritumoral abscess and asymptomatic cT4 stage
4. To evaluate the diagnostic process of detection of locoregional recurrence
5. To determine the place of isolated locoregional recurrence within the whole spectrum of recurrent disease (incidence and predictive factors of preceding and subsequent distant metastases)
6. To evaluate the classification of locoregional recurrence (anastomotic, peritoneal, nodal/mesentery, retroperitoneal) based on location regarding its relevance for clinical decision making and outcome.
7. Determine type of treatment of the locoregional recurrence (chemotherapy, radiotherapy, surgery, combination of treatments) and associated short and long-term surgical and oncological outcomes
8. Referral pattern for treatment of primary complex colon cancer and locoregional recurrence.
9. Comparison of outcome of complex colon cancer treatment depending on setting (secondary or tertiary hospital) and annual volume.

Study design

A retrospective collaborative cross-sectional research project will be conducted in >70 hospitals in the Netherlands. All patients that underwent a resection for stage I-III colon cancer in 2014/2015 will be identified from the DCRA registry. Through the Snapshot Research design, collaborators will be asked to validate these data, in a web-based tool, based on individual patient files. The validated data will be used to identify all patients with infectious, cT4 and locoregional recurrent colon cancer. This will form the first phase of this project (2021). Detailed diagnostic, procedural and treatment data and long term surgical and oncological outcomes of the primary complex colon cancers will be collected during the second phase (2021-2023). In the third phase (2022-2023), detailed treatment data and long-term outcomes of locoregional recurrences will be collected.

Study population

All patients that underwent a resection for stage I-III colon cancer in 2014/2015 will be identified from the DCRA registry. The patients with an cT4 tumor or an infectious complication (perforation/abscess) at initial presentation in 2014/2015 will be included for further analysis. Furthermore, all patients who were initially treated for stage I-III colon cancer during 2014/2015 and developed a locoregional recurrence, during at least 5-year follow-up, will be included.

Main expected results

It is expected that this snapshot study will demonstrate substantial variety among hospitals in the treatment of complex colon cancer and locoregional recurrence considering patient selection, (neo)adjuvant therapies, and surgical procedures. Furthermore, the study will provide insight into referral patterns for cT4 tumors and locoregional recurrence and the associated impact on treatment and outcome. Based upon this real-world evidence, best practice can probably be identified and guideline development being supported in the absence of large trials.


The first centers are expected to start in the autumn of 2021. 

New research question

In case you collaborated in this Snapshot study, you can use the collected data to answer your own research question.

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Other projects

Eleven other projects are performed by the Dutch Snapshot Research Group.

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