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Evaluation of Rectal Tumor Margin Using Confocal Endomicroscopy and Comparison to Histopathology

18 Years
Not Enrolling
Rectal Cancer, Rectal Adenocarcinoma

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Trial Information

Evaluation of Rectal Tumor Margin Using Confocal Endomicroscopy and Comparison to Histopathology

Defining the limits of resection of rectal tumors is often imprecise. The identification of
the banks of a tumor becomes critical when it comes to the decision to potentially sacrifice
the sphincter during the surgical resection. Currently tumor margins are identified by
direct examination by the surgeon, or using flexible endoscopy. Endoscopy and confocal
microscopy could provide precise images of tumor enabling the reliable definition of
resection margins.

There would be a direct benefit for the patient, whom sphincter could be preserved. pCLE
(probe-based Confocal Laser Endomicroscopy) has already been widely used for colorectal
lesions, and its value proposition has been demonstrated and validated in several studies.
This study is the first using pCLE intraoperatively. Study results may lead the use of pCLE
to validate surgical procedure decision (resection margin) and to a revision of patient
management for colorectal cancer, by adapting neoadjuvant radiochemotherapy to the patient's
responder status.

The goal is to identify tumor margin (lower pole) to optimize the resection margin, and to
limit resection of healthy rectal tissue for optimal anal sphincter preservation. Moreover,
determining the optimal date of surgery following neoadjuvant radiochemotherapy in rectal
cancer is being discussed and no consensus has been reached. Therefore, to date, there is no
formal evaluation of tumor response. This is partly due to the lack of information on tumor
state and tumor evolution over time, between the end of radiochemotherapy and surgery.
Histological follow up of tumor would provide supporting information to fill this gap.
However, frequent tumor biopsies are not possible. Alternatively, probe-based confocal laser
endomicroscopy (pCLE) could allow for a sequential analysis of tumor response. Response to
treatment could be assessed and used to define optimal date of surgical resection, depending
on patient responding status to treatment. Responding patients would undergo surgery at a
later date than non-responders, in whom surgery could be performed earlier.

Benefits of the study lay in the more accurate definition of resection margins, with its
associated potential therapeutic impact of the anal sphincter preservation and in the
definition of the optimal date of rectal tumor resection, based on response status to

Study interests are :

- Microscopic structure of tumor will be analyzed at the cellular and microvascular
levels and compared to healthy mucosa.

- Evolution of response during and following radiochemotherapy will be assessed, and will
help classify patients as responders/non responders.

- pCLE results will be compared to histopathology results on pre-treatment and resection

- Images gathered through the imaging modalities (WLE, pCLE, EUS) along with
histopathology results will be combined to create an atlas and database of rectal

Inclusion Criteria:

- Patient, male or female over 18 years old

- Patient with rectal adenocarcinoma :

- stage T1 or T2, N0 (one single evaluation, during resection)

- stage N+ or T3 (pre- and post-radiochemotherapy evaluations)

- Absence of contra-indication to rectoscopy conduct

- Patient able to understand the study and to provide written informed consent

- Patient registered with the French social security regime

Non-inclusion criteria:

- Absence of written informed consent

- Patient with known or suspected allergy to fluorescein

- Patient with history of reaction jeopardizing the vital prognosis during angiography

- Patient with history of multiple or serious allergic reaction to drugs

- Patient presenting, in the investigator's judgment, a condition or disease preventing
their participation to study procedures

- Patient pregnant or breast-feeding

- Patient within exclusion period from other clinical trial

- Patient having forfeited their freedom of an administrative or legal obligation

- Patient being under guardianship

Type of Study:


Study Design:

Endpoint Classification: Safety/Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Diagnostic

Outcome Measure:

Concordance in identification of lower pole of tumor

Outcome Description:

Identification of lower pole of tumor will be compared between pCLE (optical images, virtual biopsies) and conventional histopathology (biopsies, postoperative analysis of resected piece). Samples of tumor tissue and closest tissue thought to be disease-free. Conventional biopsies and virtual biopsies prior to radiochemotherapy start (if applicable) and during surgery.

Outcome Time Frame:

Up to 9 months

Safety Issue:


Principal Investigator

Joël Leroy, Pr

Investigator Role:

Principal Investigator

Investigator Affiliation:

Service de Chirurgie Disgestive et Endocrinienne - Nouvel Hôpital Civil - Strasbourg


France: Agence Nationale de Sécurité du Médicament et des produits de santé

Study ID:




Start Date:

July 2013

Completion Date:

July 2016

Related Keywords:

  • Rectal Cancer
  • Rectal Adenocarcinoma
  • Rectal cancer
  • Tumor margin
  • Confocal endomicroscopy
  • Virtual biopsy
  • Fluorescein
  • Adenocarcinoma
  • Adenocarcinoma, Mucinous
  • Rectal Neoplasms