Chemoprevention Trial in Familial Adenomatous Polyposis (FAP) Coli Using EPA

Inclusion Criteria:

* Subjects must have a known diagnosis of Familial Adenomatous Polyposis (FAP) and have had a previous colectomy with ileo-rectal anastomosis.
* Males or females aged 18 and over
* If the participant is female and of child bearing potential, she agrees to participate in this study by providing written informed consent, has been using adequate contraception (e.g. abstinence, condom, Intra-uterine device (IUD), birth control pill, diaphragm and spermicidal gel combination) since her last menses and will use adequate contraception during the study, is not lactating, and agrees to undergo a serum pregnancy test at baseline and month 6. Sexually active males must agree to use an accepted method of contraception.
* Rectal polyp status: the subject has an endoscopically assessable rectal segment.
* Subjects must show a willingness to abstain from regular use of non-steroidal anti-inflammatory medication for the duration of the study. A cardioprotective dose of aspirin (75mg) will be permitted.
* Subjects must have provided written informed consent to participate.
* Subjects must have assessable rectal polyps post baseline flexible sigmoidoscopy.
* Subjects must have the following rectal polyp burden at the conclusion of the baseline endoscopy:
* Rectum - 3 or more quantifiable polyps ≥2mm diameter
* In the rectum quantifiable polyps are defined as being within a composite "cloverleaf" photograph that includes a tattoo.

Exclusion Criteria:

* Subjects who are due to undergo an anticipated colectomy within 8 months of randomisation
* History of invasive carcinoma in the past 5 years other than resected Dukes' A/B1 colon cancer or resected non-melanomatous skin cancer
* Partial or complete colectomy within 12 months prior to enrolment.
* History of pelvic radiation
* Subjects who are allergic to fish
* Subjects who have diabetes mellitus
* Subjects who are pregnant or breast-feeding
* Subjects taking aspirin or other non-steroidal anti-inflammatory drugs on a regular basis other than low dose (75 mg) cardioprotective dose.
* Subjects who have aspirin-sensitive asthma
* Subjects suffering from haemorrhagic disorders
* Subjects who are taking warfarin or other anticoagulants
* Subjects who have significant abnormalities on their screening blood tests
* Subjects taking lipid lowering medication
* Subjects with gastrointestinal malabsorptive disease
* Subjects with known or prior coagulopathy
* Subjects with uncontrolled hypercholesterolaemia
* Subjects who are taking other fish-oil supplements (e.g. cod liver oil) who are unwilling to stop them for the duration of the study. Subjects previously taking fish oil must have a washout period of 1 month prior to study enrolment.
* Subjects who are deemed mentally incompetent, or have a history of anorexia nervosa or bulimia
* Subjects with a history of alcohol or drug abuse, including laxative abuse which would render the subject unreliable.
* Subjects considered by their physician unlikely to be able to comply with the protocol.
* Subjects who have taken part in an experimental drug study in the preceding 3 months.
* Subjects who have a positive pregnancy test within 14 days prior to baseline visit.