Neoplasms

Digestive System Diseases

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Rectal Neoplasms

Colorectal Neoplasms

Intestinal Neoplasms

Gastrointestinal Neoplasms

Digestive System Neoplasms

Gastrointestinal Diseases

Intestinal Diseases

Rectal Diseases

Central Nervous System Depressants

All Drugs and Chemicals

Anesthetics

In addition to standard workup and treatment, patients will undergo pre-operatively, after induction of general anaesthesia, an endorectal ultrasound and rigid rectoscopy as study procedures if these are not part of standard workup yet.

Ultrasound

Rectoscopy

For some patients, images of the resection specimen (note: NOT of the patients) during the pathological process will be acquired.

Scan, e.g. CT (resection specimen)

Maaike Berbée, MD, PhD

Evert Van Limbergen, MD, PhD

Jarno Melenhorst, MD, PhD

An-Sofie Verrijssen, MD

Pim Burger, MD, PhD

The aim of the study is to provide prospective data regarding microscopic tumor spread in all directions from the macroscopic tumor in pathology specimens, as seen by eye, and on imaging to define the target volume for endoluminal radiation boosting in rectal cancer patients.

This study is a prospective multicentre cohort trial in ≥50 patients with a residual ycT1-3N0 tumor after neoadjuvant chemoradiotherapy or radiotherapy for rectal adenocarcinoma at least 6 weeks after the neoadjuvant treatment.

In addition to standard workup and treatment (e.g. a flexible endoscopy and an MRI scan at 6-8 weeks post-neoadjuvant therapy), patients will undergo pre-operatively, after induction of general anaesthesia, an endorectal ultrasound and rigid rectoscopy as study procedures if these procedures are not already part of standard workup. Furthermore, the pathological specimens of some patients will be scanned using MR imaging during certain parts of the pathological process.

Objectives include determining the maximum distance of microscopic tumor spread per patient in all directions, creating a tissue deformation model to account for changes due to e.g. fixation and pathological processing, using this tissue deformation model to translate the microscopic tumor spread back to the in vivo situation (e.g. back to in vivo MRI scans, 3D endo-ultrasounds), and evaluating/determining risk factors for the presence and/or extent of microscopic tumor spread.

This data will be used for target volume definition in rectal endoluminal radiation boosting.

* The (re)biopsy material
* (Part of) the material of the pathological rectal specimen after TME surgery

Both are part of standard clinical care.

DETECT: Target Volume for Rectal Endoluminal Radiation Boosting

DETECT: Defining the Target Volume for Endoluminal Radiation Boosting in Patients With Rectal Cancer

The data will not be shared with other researchers, however the following applies if patients have given specific, additional consent:

If patients have consented to the use of leftover body material and/or data in further studies, the deidentified images (endoscopy, rectoscopy, ultrasound, in vivo MRIs and specimen MRIs) and pathological specimens/samples including (re)biopsies, and the accompanying data can be used for further scientific research related to rectal cancer by the investigators, including investigators from collaborating institutions, without requiring additional informed consent.

Potential risk factors include among others ycT stage, regrowths/local recurrence, diameter, predominant histologic grade, tumor regression score/grade (pathologically), vascular invasion, lymphatic invasion, perineural invasion, microsatellite instability (MSI) and parameters related to in vivo MR imaging.

This includes the biopsy material at time of diagnosis, and also the rebiopsy material for patients with tumor regrowths/local recurrence after an initial clinical complete response and a "watch and wait" approach. These (re)biopsies are a part of the standard diagnostic work-up. Part of this analysis will be performed during this study by reassessment of the histology of the biopsy material and/or if applicable the rebiopsy material.

The maximum distance of microscopic tumor spread in all directions from the macroscopic remnant in the specimen will be measured per patient in millimeters by the pathology department in the pathologic resection specimens.

Measured per patient in millimeters by the pathology department in the pathologic resection specimens. Microscopic tumor spread perpendicular to the bowel wall and parallel to the bowel wall will be reported separately.

Measured per patient in millimeters by the pathology department in the pathologic resection specimens. For this secondary outcome, this will be reported excluding all ypT0 patients.

Measured per patient in millimeters by the pathology department in the pathologic resection specimens. For this secondary outcome, this will be reported only for patients with microscopic tumor spread.

Measured per patient in millimeters by the pathology department in the pathologic resection specimens. For this secondary outcome, this will be reported only for patients with regrowths.

The deidentified images of the flexible endoscopy and in vivo MRI scan will be collected for the study. During the certain parts of the pathologic process, e.g. before and after fixation, MRIs of the pathological specimens of some of the patients will be made. These deidentified images of the specimens, together with e.g. the deidentified endoscopic, rectoscopic, ultrasound and in vivo MR images and possibly with optical images taken during pathological analysis, will be used to develop the deformation model.

The flexible endoscopy and in vivo MRI scan are both taken approximately 6-8 weeks post-neoadjuvant treatment. The images of the rigid rectoscopy and 3D endorectal ultrasound are taken directly before TME surgery.

The tissue deformation factor/model and the location of the microscopic tumor spread in relation to the macroscopic remnant determined during pathological analysis, will be used to determine the maximum distance of microscopic tumor spread in relation to the macroscopic tumor as seen by eye (rectoscopically/endoscopically) and/or on imaging (endo-ultrasound, MRI) per patient in all directions.

The flexible endoscopy and in vivo MRI scan are both taken approximately 6-8 weeks post-neoadjuvant treatment. The images of the rigid rectoscopy and 3D endorectal ultrasound are taken directly before TME surgery.

Distance that covers the microscopic tumor spread in all directions in millimeters for 90 and 95% of patients, including 95% confidence intervals, both reported including and excluding ypT0 patients. Reported both by eye and on imaging, for which among others the tissue deformation model will be used.

These risk factors include pathological T stage after chemoradiation (ypT stage) and time interval between neoadjuvant chemoradiotherapy and surgery.

Study title	NCT ID	Conditions	Interventions	Eligibility	Organization	Link
DETECT: Target Volume for Rectal Endoluminal Radiation Boosting	NCT04927897	Rectal Cancer	Ultrasound Rectoscopy Scan, e.g. CT (...	18 Years -	Maastricht Radiation Oncology
DETECT: Target Volume for Rectal Endoluminal Radiation Boosting	NCT04927897	Rectal Cancer	Ultrasound Rectoscopy Scan, e.g. CT (...	18 Years -	Maastricht Radiation Oncology

Spots Global Cancer Trial Database for target volume definition