Healing of Rectal Anastomosis Sealed With a Concentrate Derived From the Patient's Blood, After Rectal Cancer Surgery

Obsidian in Anastomotic Healing After Rectal Cancer Resection: A Prospective Clinical Feasibility Study

Rectal cancer is one of the most frequent cancer diseases, with more than 1500 new cases per year in Denmark. Fortunately, if the tumor is discovered early, surgeons can remove the part of the intestine that is afflicted, and they can often sew the intestine-ends back together, forming what is known as an anastomosis. However, in 10-15% of cases, this anastomosis doesn't heal completely, leading to anastomotic leakage. This is a serious complication, with detrimental effects for the individual patient. Previous measures to avoid this complication, have proven unsuccessful.

Obsidian is a mixture derived from the patients' own blood, that contains components of blood normally responsible for stopping bleeding and kickstarting the healing process. It is already used in other clinical settings and preliminary, yet unpublished, results from a pilot study have shown its promise in decreasing the risk of anastomotic leakage in rectal anastomosis. However, its use has not been examined when performing surgery for rectal cancer with minimally invasive technique, which is today's standard.

The main clinical hypothesis of this feasibility study is that it is possible for colorectal surgeons to apply Obsidian successfully on the anastomotic area with minimal invasive technique, as a supplement during rectal cancer resection with anastomosis.

This study will be conducted at the Department of Surgery, Aarhus University Hospital. 50 patients will be included, who will undergo minimally invasive rectal cancer surgery with an anastomosis. Right after the onset of anaesthesia, 120 ml of blood will be collected from the patient and will be processed, making a 5-6 ml Obsidian concentrate. When the tumor-bearing part of the rectum has been removed, Obsidian will be applied, according to a pre-specified protocol.

If the application is deemed successful (based on predefined assessment criteria) in at least 90% of our included patients, then this study will serve as a stepping stone for a bigger study, the aim of which will be to assess if this method can indeed bring down the rate of anastomotic leakage in such patients.

Inclusion Criteria:

• Primary rectal cancer (adenocarcinoma) with the lower boarder within 15 cm from the anal verge assessed by rigid proctoscopy
• Clinical UICC stage I-III at time of rectal cancer diagnosis
• Deemed suitable for intended curative rectal cancer resection at MDT either by total mesorectal excision (TME) or partial mesorectal excision (PME)
• Scheduled for elective, minimal invasive surgery
• ECOG performance status 0-2
• Age at least 18 years
• Written and orally informed consent

Exclusion Criteria:

• Distant metastatic disease
• Locally advanced rectal cancer requiring extended resection
• Open surgery
• Benign lesions of the rectum
• Inflammatory bowel disease
• Another malignant disease within previous 2 years
• Inability and unwillingness to give informed consent
• Pregnant (positive pregnancy test) or breast feeding women