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Does the use of adjunct histopathological techniques to enhance lymph node yield improve tumour staging in colorectal cancer?

Student thesis: Doctoral Thesis

Aims and scope: The Royal College of Pathologists recommend at least 12 lymph nodes should be harvested for adequate staging of colorectal cancer. Just one nodal tumour deposit upstages the malignancy. This is important as node-positive patients are considered for adjuvant chemotherapy whereas node negative patients may not be. It is not always easy to harvest the required number, especially in patients with rectal cancer receiving neoadjuvant therapy which further decreases the number and size of nodes.
Lymph node revealing solutions, e.g. GEWF have been investigated to help improve nodal retrieval. GEWF is safe, cheap and easy to use, improving nodal retrieval and possibly cause upstaging, triggering adjuvant chemotherapy. However, existing evidence to support this argument is limited.

Methods: A controlled trial was designed, comparing further formalin fixation (n=101) to GEWF (n=99). Colorectal resections were placed in formalin or GEWF for 24 hours before performing a secondary dissection. The number, size and any tumour in nodes was compared between groups.

Results: The use of formalin further fixation and GEWF detected more nodes at secondary dissection. The mean number of additional nodes harvested was greater with formalin (8.3) in comparison to GEWF (7.3). When compared to formalin, GEWF does not cause a statistically significant increase in node numbers in the entire sample (p=0.218), non-neoadjuvant group (p=0.226) or neoadjuvant group (p=0.569).
When compared to formalin, GEWF does not find statistically significant smaller nodes in the entire sample (p=0.093), non-neoadjuvant group (p=0.053), or neoadjuvant group (p=0.730). Upstaging triggering adjunct chemotherapy was identified in 2/200 cases.

Conclusions: The routine use of adjunct techniques is unnecessary with underlying high quality dissection practice. Emphasis should be placed upon educating and training staff, spending appropriate time dissecting, and ensuring specimens are sufficiently fixed beforehand.

Contribution: This research is the first to provide robust statistical analysis regarding the efficacy of adjunct techniques in colorectal cancer. Further research could be performed to assess their use in other cancers where nodes are difficult to detect.
Original languageEnglish
Awarding Institution
Supervisors/Advisors
  • Dr Isobel Ryder (Supervisor)
  • Norman J Carr (External person) (Supervisor)
  • Myra Wilkinson (Supervisor)
Award dateDec 2014

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