Intervention: Doconexent
Trial phase: Phase 2
SMILES: CC/C=C\C/C=C\C/C=C\C/C=C\C/C=C\C/C=C\CCC(=O)O
Sex: Female
Age groups: Adult | Older Adult
Healthy volunteers: No
Participants at risk: 32
Group description: Docosahexaenoic Acid 1000 mg orally twice a day for 12 weeks.
Eligibility criteria:
Inclusion Criteria:

Participants must have a history of histologically-confirmed stage I-III invasive breast cancer or ductal carcinoma in situ (DCIS), Paget's disease, lobular carcinoma in situ (LCIS), or proliferative benign breast disease
No evidence of disease (in situ or invasive cancer that would normally be treated by resection) at trial entry as determined by the investigator
>= 6 months from all previous breast cancer treatment (including surgery for invasive cancer, chest wall radiotherapy, chemotherapy, trastuzumab and endocrine therapy)
Participants must have a body mass index (BMI) >= 25, defined as (weight in kilograms/[height in meters]^2)
Participants must have adequate accessible breast tissue as determined by the treating physician, consisting of one breast unaffected by invasive cancer, which has not been radiated; a history of prior pre-invasive breast cancer or benign biopsy of this breast will be permitted
Daily DHA consumption =< 200 mg/day in the month prior to screening estimated by an abbreviated DHA food frequency questionnaire
Mammogram within no more than 6 months prior to the date of informed consent (normal/benign Breast Imaging-Reporting and Data System [BI-RADS] 1 or 2) and no further routine breast imaging planned during the course of the study (12 weeks DHA/placebo)
Eastern Cooperative Oncology Group (ECOG) performance status must be =< 2 (Karnofsky >= 60%)
Absolute neutrophil count >= 1,500/uL
Platelets >= 75,000/uL
White blood cells >= 3,000/uL
Hemoglobin >= 10 g/dL
Total bilirubin within 1.5 times the institution's upper limit of normal (ULN)
Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase [SGOT])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase [SGPT]) within 1.5 times the institution's ULN
Serum creatinine within 1.5 times the institution's ULN
Pregnant women will be excluded; for women of childbearing potential; negative pregnancy testing within 72 hours prior to or on study visit #1 (day 0) and willingness to use adequate contraception during the study intervention OR post-menopausal defined as any one of the following 1) prior hysterectomy, 2) absence of menstrual period for 1 year in the absence of prior chemotherapy or 3) absence of menstrual period for 2 years in women with a prior history of chemotherapy exposure who were pre-menopausal prior to chemotherapy
Willingness to comply with all study interventions and follow-up procedures including the ability to swallow the study drug
Ability to understand and the willingness to sign a written informed consent document

Exclusion Criteria:

Any type of active invasive cancer (excluding breast and non-melanoma skin cancer) within the preceding 18 months
A history of histologically-confirmed bilateral invasive breast cancer
Bilateral mastectomy
Prior history or evidence of metastatic breast cancer
Prior radiation therapy to the contralateral (unaffected) breast
Prior history of contralateral (unaffected) breast augmentation with breast implant placement
History of daily use of aspirin or non-steroidal anti-inflammatory drugs (NSAIDs) in the week preceding study entry
History of DHA supplementation > 200 mg/day in the month preceding study entry
History of autoimmune disorder or any illness that requires therapy with chronic steroids or immunomodulators
History of therapeutic doses of anticoagulants including warfarin and low molecular weight heparin (e.g. for prior deep venous thrombosis and pulmonary embolism) in the preceding year
Participants may not be receiving any other investigational agents during the study
Women who have received cancer surgery, chemotherapy, biological therapy (e.g., trastuzumab), or radiotherapy for the treatment of any cancer within 6 months of study participation
Women who are receiving endocrine therapy for breast cancer treatment or chemoprevention including tamoxifen, letrozole, anastrozole, fulvestrant, or exemestane at the time of screening
Individuals with severe underlying chronic illness, such as uncontrolled diabetes; ongoing or active infection, psychiatric illness or social situations which in the opinion of the investigator would interfere with study participation
History of allergic reactions attributed to compounds of similar chemical or biologic composition to DHA or corn/soy oil in placebo agent
Pregnant, breastfeeding, or women of childbearing potential unwilling to use a reliable contraceptive method