Inclusion Criteria:

- Women diagnosed with breast cancer stages I-III initiating first adjuvant AI therapy
with any of the Food and Drug Administration- (FDA) approved AIs (anastrozole,
exemestane, letrozole)

- Concurrent gonadotropin-releasing hormone (GnRH) agonist therapy is allowed

- Concurrent breast related radiation therapy is allowed

- Prior tamoxifen use is allowed

- Prior chemotherapy is allowed

- History of osteoarthritis and/or fibromyalgia is allowed

- Ability to understand and the willingness to sign a written informed consent document

Exclusion Criteria:

- Metastatic malignancy of any kind

- Rheumatoid arthritis and other types of autoimmune and inflammatory joint disease,
with the exception of osteoarthritis and fibromyalgia

- AI use > 2 weeks prior to study enrollment

- Known bleeding disorders

- History of diabetes mellitus, heart disease or TIA/stroke

- Current use of warfarin or other anticoagulants

- Uncontrolled intercurrent illness including, but not limited to, ongoing or active
infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac
arrhythmia,or psychiatric illness/social situation that would limit compliance with
study requirements

- Daily use of n-3 PUFA concentrates or capsules or regular or any other supplements
that might interact with n-3 PUFA supplements within six months of study initiation;
sporadic use of n-3 PUFA supplement may be eligible if there has been a 3-month
washout period prior to randomization

- Pregnant or nursing women

- Known sensitivity or allergy to fish or fish oil

- Concurrent use of daily full dose aspirin (≥ 325 mg/day), nonsteroidal
anti-inflammatory drugs (NSAIDs) or NSAID-containing products or steroids; one month
washout period is required prior to randomization

- Unable to give informed consent

- In patients consenting for optional MRIs, any contraindication to MRI examination
including but not limited to ferromagnetic metal in the body, pacemaker, or severe
claustrophobia