Trial document




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  DRKS00012758

Trial Description

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Title

How reliable are rectoscopic measurements to determine the height of rectal carcinoma?

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Trial Acronym

none

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URL of the Trial

http://none

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Brief Summary in Lay Language

In patients with malignant tumors of the rectum (“rectal carcinoma”), the measured height from the anal verge is taken as a major criterion to decide for or against radiation and chemotherapy prior to an operation (“neoadjuvant chemo-radiation”). To measure the tumor height, a rigid endoscope (“rectoscope”) is usually employed and rigid rectoscopy considered as gold standard. Differences in measurements of only a few mm may have fundamental consequences for further therapy planning. It should therefore be assumed that rectoscopic measurements are universally reliable and reproducible. However, there is no scientific confirmation for this assumption. On the contrary, it seems much more likely that rigid rectoscopy may exhibit a similar variability of results and dependency on the examiner and examination conditions (such as positioning of the patient) as do most other clinical examination methods.

With this study we therefore want to establish whether a simple height measurement by rigid rectoscopy is reliable enough to be taken as basis for the decision to advice for or against neoadjuvant therapy in patients with rectal carcinoma.

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Brief Summary in Scientific Language

The aim of this study is to evaluate the reproducibility of rigid rectoscopic height measurements of rectal carcinoma performed by different examiners in different examination positions.

The measured distance of a rectal carcinoma from the ano-cutaneous line (ACL) is a decisive factor for the decision for or against neoadjuvant therapy as only the lower rectum is accessible for radiotherapy. In this context a “12 cm rule” is generally accepted. Measured from the ACL, this distance is considered the watershed line separating the upper third of the rectum from the lower two thirds.
The following excerpt is taken from the current German S3-guidelines for colorectal carcinoma published under the seal of the “Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften” (AWMF)1:
“According to UICC 2003, rectal cancer are subdivided according to the distance from the anocutaneous line into cancer of the upper rectal third (12-16cm), the middle rectal third (6-<12 cm), and the lower rectal third (<6cm). In contrast, in the US [514, 515], colon cancer have by definition a distal margin of more than 12 cm and rectal cancer a distal margin of less than 12 cm from the anocutaneous line. This is based on the significantly higher local recurrence rate of tumors with less than 12cm distance from the anocutanoeus line.”(1)
On the one hand, these guidelines suggest that the surgical approach should primarily be based on tumor height above or below 12 cm:
“With tumors of the upper third of the rectum, resection of the rectum with partial mesorectal excision 5 cm distal to the macroscopic tumor border, measured in-vivo should be performed. The mesorectum should be dissected horizontally without proximal thinning (no coning). … With tumors of the middle and lower third of the rectum, a total mesorectal excision (TME) should be performed up to the pelvic floor, preserving the superior and inferior hypogastric plexus and the hypogastric nerves.” (2)
More decisive still, tumor height is taken as main basis to advice for or against neoadjuvant chemo-radiation:
“The relevance of radiation therapy for cancers in the upper third of the rectum is considered controversial. Adjuvant therapy as for colon cancer or perioperative radio(chemo)therapy as for rectal cancer can be performed…. The following arguments speak in favor of treating the upper third of the rectum (> 12- 16 cm from the anocutaneous line, measured with a rigid rectoscope) in the same way as colon cancer:
• Data from American studies on adjuvant therapy which established radiochemotherapy for treatment of rectal cancer, were based exclusively on rectal tumors showing a margin of up to 12 cm in between the distal edge of the tumor and the anocutaneous line.
• The Dutch TME study showed no significant improvement of the local diseaserecurrence rate by additional radiotherapy for tumors of the upper third of the rectum (here defined as: 10-15 cm from the anocutaneous line).” (3)
To measure the tumor height, a rigid endoscope (“rectoscope”) is usually employed and rigid rectoscopy considered as gold standard.
“The prediagnostic work up of a patient with rectal cancer should include a rigid rectoscopy with a statement on the distal tumor or margin. … Rigid rectoscopy allows an exact determination of the distance of the distal tumor margin from the dentate line and is of major importance for determining further therapy. (4)
As a result of this ongoing debate, patients with rectal carcinoma of the upper third of the rectum (i.e. above 12cm) are now excluded from neoadjuvant therapy in most centers.
Therefore, minor differences in measurements of just a few mm may result in major differences of oncological treatment. The importance of rigid rectoscopy for setting the further course of therapy implicitly assumes that in all cases and under all conditions this examination procedure always renders reliable and reproducible results. However, there are no firm data for this assumption. It is further remarkable that the “12 cm rule” is assumed to apply to all patients, irrespective of body size and sex, and also that there are no defined standards for the technicalities of this examination, such as positioning of the patient (lithotomy or left lateral) or prior enema application. However, it seems likely that rigid rectoscopy may exhibit a similar variability of results and dependency on the examiner and examination conditions as do most other clinical examination methods. This corresponds to experiences made in specialized coloproctological practice, where rigid rectoscopy is frequently performed on a regular basis.
A further issue is the fact that the anocutaneous line (ACL) is actually not truly suitable as landmark for height measurements within the rectum. The ACL is defined as the transition from anoderm to perianal skin. This demarcation is easily visualized; it surrounds the anus about one to two cm lateral to the anal verge. The ACL may vary depending on different degenerative proctologic disorders, particularly in cases of anal prolapse as accompanying feature of hemorrhoid disease. The position lateral to the anal verge complicates axial measurements by rigid rectoscopy. As a result most examiners will estimate and add the lateral distance to their measurement or for simplicity’s sake (or by ignorance) will take the anal verge as measuring limit. In any case, this presumably is also a source of some blurring of height measurements.



Literature:

1. German Guideline Program in Oncology (German Cancer Society, German Cancer Aid, AWMF): Evidenced-based Guideline for Colorectal Cancer, long version 1.0, AWMF registration number: 021-007OL, http://leitlinienprogrammonkologie. de/Leitlinien.7.0.html: 89

2. ibid. 107-108
3. ibid. 138-139
4. ibid. 99

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Organizational Data

  •   DRKS00012758
  •   2017/07/20
  •   [---]*
  •   yes
  •   Approved
  •   2017-282-f-S, Ethik-Kommission der Ärztekammer Westfalen-Lippe und der med. Fakultät der Westfälischen Wilhelms-Universität Münster
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Secondary IDs

  • [---]*
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Health Condition or Problem studied

  •   C20 -  Malignant neoplasm of rectum
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Interventions/Observational Groups

  •   In patients with rectal carcinoma: collection of rectoscopic tumor height measurements performed by different examiners and in different examination positions (left lateral vs. lthotomy)
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Characteristics

  •   Non-interventional
  •   Observational study
  •   Single arm study
  •   Open (masking not used)
  •   [---]*
  •   Uncontrolled/Single arm
  •   Diagnostic
  •   Single (group)
  •   N/A
  •   N/A
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Primary Outcome

differences in tumor height measured by different examiners and in different examination positions (left lateral vs. lthotomy)

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Secondary Outcome

- potential influence of differences in height measurements on further therapy planning
- differences in assessment of Mason-criteria depending on examiner and examination Position
- diffreneces in height measurements by rigid rectoscopy and by MRT

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Countries of Recruitment

  •   Germany
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Locations of Recruitment

  • Medical Center 
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Recruitment

  •   Planned
  •   2017/10/02
  •   50
  •   Monocenter trial
  •   National
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Inclusion Criteria

  •   Both, male and female
  •   18   Years
  •   no maximum age
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Additional Inclusion Criteria

Patients with diagnosed rectal carcinoma

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Exclusion Criteria

none

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Addresses

  • start of 1:1-Block address primary-sponsor
    • Abteilung Allgemein- und Viszeralchirurgie, KoloproktologieSt. Barbara-Klinik Hamm
    • Mr.  Priv.-Doz. Dr. med.  Matthias  Kraemer 
    • Am Heessener Wald 1
    • 59073  Hamm
    • Germany
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    • Abteilung Allgemein- und Viszeralchirurgie, KoloproktologieSt. Barbara-Klinik Hamm
    • Mr.  Priv.-Doz. Dr. med.  Matthias  Kraemer 
    • Am Heessener Wald 1
    • 59073  Hamm
    • Germany
    end of 1:1-Block address scientific-contact
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    • Abteilung Allgemein- und Viszeralchirurgie, KoloproktologieSt. Barbara-Klinik Hamm
    • Mr.  Priv.-Doz. Dr. med.  Matthias  Kraemer 
    • Am Heessener Wald 1
    • 59073  Hamm
    • Germany
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Sources of Monetary or Material Support

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    • Abteilung Allgemein- und Viszeralchirurgie, KoloproktologieSt. Barbara-Klinik Hamm
    • Mr.  Priv.-Doz. Dr. med.  Matthias  Kraemer 
    • Am Heessener Wald 1
    • 59073  Hamm
    • Germany
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Status

  •   Recruiting planned
  •   [---]*
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Trial Publications, Results and other Documents

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* This entry means the parameter is not applicable or has not been set.