You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Outcome", "Participant", "Intervention"].

Please return the output as a JSON object of the format: {"Participant" : ["patients with COPD", ...], "Intervention" : ["Atenolol", ...], "Outcome" : ["blood pressure", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Intraluminal exfoliated cancer cells and effectiveness of bowel ligatures during sigmoidectomy for sigmoid colon cancer . PURPOSES To establish the efficiency of bowel ligatures in colon cancer surgery , focusing on the extent to which exfoliated cancer cells are shed in the colonic lumen during sigmoidectomy . METHODS Twenty consecutive patients who underwent sigmoidectomy for sigmoid colon cancer were prospectively randomized into two groups : the " ligatures group " , in which bowel ligatures were placed , 3 , 5 , 10 cm from the tumor proximally and distally before dissection ; and the " no ligatures group " , in which the corresponding sites were ligated only immediately before taking the specimen out . Each colonic segment ligated was irrigated with saline and samples were sent for blind cytological examination . RESULTS Cancer cells were found in the colonic segment where the tumor was located , in 18 of 20 samples . The frequency of free cancer cells decreased from 50 to 0 % ( p < 0.04 ) in the distal 3-5 cm colonic segment and from 80 to 20 % ( p < 0.03 ) in the proximal colonic segment after performing bowel ligatures . Free cancer cells were confirmed in 1 of 10 samples at both colonic segments 5-10 cm from the tumor , even after bowel ligatures . CONCLUSIONS Intraluminal exfoliated cancer cells could be eliminated by placing bowel ligatures during sigmoidectomy . Measures should be considered to eliminate exfoliated cancer cells during colectomy , even after placing bowel ligatures .
{"Intervention": [".", "irrigated with saline", "ligatures group", "colon cancer surgery", "sigmoidectomy"], "Outcome": [], "Participant": ["during sigmoidectomy for sigmoid colon cancer", "sigmoidectomy for sigmoid colon cancer", "Twenty consecutive patients", "during colectomy", "colon cancer surgery"]}