Rectal cancer 2.0

2nd Snapshot Rectal cancer

– The sixth Dutch Snapshot study –

PArticipating centers

28th of February 2022


28th of February 2022


The treatment of rectal cancer is complex and constantly changing. A previous Snapshot study has been performed in which all rectal cancer resections performed in the Netherlands in 2011 were evaluated. This appeared to be a reliable and valid research tool to establish detailed knowledge of nationwide clinical outcomes and it led to a total of 9 publications. By repeating the Snapshot study, we can evaluate the changes in time and this can lead to acknowledgement of new shortcomings. One known shortcoming is the lack of recognition of enlarged lateral lymph nodes. Low T3/T4 tumors have the tendency to spread to lateral lymph nodes which gives a considerable chance of a local recurrence. So far there is no consensus on diagnosis and treatment of these enlarged lymph nodes.


1) By comparing the results between 2011 and 2016 the fast developing rectal cancer care can be evaluated, including a guideline revision and new surgical techniques
2) Reassessment of the MRI of high-risk tumors by trained radiologists may reveal missed information such as enlarged lateral lymph nodes that were not mentioned in the initial report.
3) Reassessment of the radiation fields of patients with enlarged lateral lymph nodes will clarify whether these lymph nodes were included. This will lead to awareness in the variation of the radiation fields.

Study design

A retrospective, cross-sectional collaborative research project will be performed. All hospitals in the Netherlands will be asked to participate. Short term data have already been collected in the Dutch ColoRectal Audit (DCRA) and the dataset of the year 2016 will be extended with more detailed data of diagnostics, pre-treatment, procedure and the long-term results. In addition, the MRI’s and radiation fields of high-risk tumors will be reassessed by the local radiologist and radiotherapist to evaluate the variation in assessment and treatment of the lateral lymph nodes. Per hospital a surgeon, one or two surgical residents, a radiologist and a radiotherapist are asked to participate in this study.

Study population

1. Data collection by surgical residents: all patients having undergone rectal cancer resections in 2016
2.  Data collection by radiologists: low T3/T4 rectal cancers
3. Data collection by radiotherapists: low T3/T4 rectal cancers with enlarged lateral lymph nodes

Main outcomes

1) The influence of different variables on surgical and oncological outcomes
2) The variation in acknowledgement and treatment of enlarged lateral lymph nodes


The three different data collections will follow in sequence (surgical residents -> radiologists -> radiotherapists).
Every month a group of hospitals will be opened for inclusion after the study is approved by the local Board of Directors. The first centers started in October 2020.

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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