Inclusion Criteria - Pre-Registration:

• Age ≥ 18 years and ≤ 45 years of age.
• Presence of lesion suspicious for benign breast disease on mammography and planned breast biopsy.
• Had a live birth ≤ 5 years prior to pre-registration.
• Pre-menopausal.
• Provide written informed consent.
• Ability to complete questionnaire(s) by themselves or with assistance.
• Willingness to provide mandatory blood and urine specimens for correlative research.
• Willingness to provide mandatory tissue specimens for correlative research.

Inclusion Criteria - Registration:

• Age ≥ 18 years and ≤ 45 years of age.
• Histological confirmation of benign breast disease (i.e., no evidence of DCIS or invasive cancer).
• Registration must be completed ≤ 30 days after pre-registration biopsy performed for this study.
• Hemoglobin ≥ 9.0 g/dL (obtained ≤ 30 days prior to registration).
• Platelet count ≥ 100,000/mm^3 (obtained ≤ 30 days prior to registration.
• Serum creatinine ≤ 2.0 mg/dl (obtained ≤ days prior to registration).
• Negative pregnancy test done ≤ 7 days prior to registration.
• Willing to use contraception while on treatment.
• Provide written informed consent.
• Ability to complete questionnaire(s) by themselves or with assistance.
• Willingness to provide mandatory blood and urine specimens for correlative research.
• Willingness to provide mandatory tissue specimens for correlative research.
• Willing to return to enrolling institution for follow-up.

Exclusion Criteria - Pre-Registration:

• History of breast cancer including ductal breast carcinoma in situ (DCIS).
• Received systemic treatment for any other cancer at any time.
• Currently taking aspirin or other non-steroidal anti-inflammatory drugs (NSAIDS) (no doses within ≤ 5 days prior to pre-registration and no more than four doses within ≤ 30 days prior to pre-registration).
• Currently taking other agents for the prevention of breast cancer.
• Currently taking anticoagulants.
• Contraindication for aspirin use.

Exclusion Criteria - Registration:

• No research tissue collected during pre-registration biopsy performed for this study.
• Currently taking aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs).
  • NOTE: no doses within ≤ 5 days prior to registration and no more than four doses within ≤ 30 days prior to registration.
• Co-morbid illnesses/conditions which, in the judgment of the investigator, would make the patient inappropriate for entry into this study or interfere significantly with the proper assessment of safety and toxicity of the prescribed regimens.
• Any contraindication to aspirin use including but not limited to:
  • Bleeding disorders (e.g., hemophilia);
  • Stomach or intestinal bleeding ≤ 6 months prior to registration;
  • Known allergy to other non-steroidal anti-inflammatory drugs (NSAIDs).
• Currently taking anticoagulants.
• Any malignancy requiring systemic therapy.
• Currently pregnant or planning to become pregnant in the next 90 days.
• Post-menopausal:
  • Prior bilateral surgical oophorectomy; or
  • No menses for > 1 year with estradiol levels within postmenopausal range, according to institutional standard.

Eligibility last updated 1/3/23. Questions regarding updates should be directed to the study team contact.