Experimental, clinical, and epidemiological studies have all demonstrated the strong association between chronic inflammation and cancer, and many studies have correlated the prolonged presence of the inflammatory milieu with an increased risk for developing cancer.(1) Although the potential mechanism for aspirin preventing breast cancer is not known, possible pathways may involve platelets, inflammation, cyclooxygenase (COX) 2, hormones, or PI3 kinase. (2).

In actual clinical practice there exist clear guidelines for the use of aspirin in colorectal cancer but no such guidelines exist for the use of aspirin in breast cancer patients.

In the Unit´s proper experience, in patients under active surveillance and metastatic ones some present very good responses both in the neoadjuvant and in the metastatic setting but investigators intend to provide evidence and not just the experience. This study patients are proposed to combine their standard treatment with aspirin.

Breast cancer patients with diagnosis of Ductal or Lobular Invasive Carcinoma or CDis that refuse to underwent surgery or are not qualified for, and independently of age or of their actual staging, are going to be allocated, randomly and in double masked way to one of two arms:

Arm 1: standard Unit´s protocol + placebo Arm 2: standard Unit´s protocol + aspirin

Inclusion Criteria:

Every adult (above 18) y.o.patient with histologic diagnosis of Breast Cancer that refuse or is not suitable for surgical treatment, or with metastatic disease, remaining this way in an "active surveillance"

Exclusion Criteria:

Allergy or toxicity to aspirin