OBJECTIVE:

To determine the cumulative incidence of breast cancer at five years of follow-up in patients with preinvasive or premalignant lesions of the mammary gland in a referral canter and to establish the associated risk factors.

MATERIALS AND METHODS:

Retrospective cohort study carried out in patients seen at Hospital Ángeles Lomas between 2012 and 2016 with a diagnosis, during their mastographic screening, of a precursor or pre-invasive lesion of breast cancer. Categorical variables are expressed in frequencies and percentages. The χ2 test was used for difference of proportions between groups.

RESULTS:

We obtained 3360 patients who attended the mastology service during the established time. We obtained 245 patients with premalignant lesions but 30 of them did not comply with the five-year follow-up and were lost within the stipulated surveillance period. This left 215 patients who met all the inclusion criteria. The overall cumulative incidence of invasive breast cancer was that at 5 years 14.9% of patients with premalignant lesions will have breast cancer. Lobular carcinoma in situ had the highest incidence or progression of invasive cancer, with 32.1% at 5 years, followed by mucocele-like lesions, ductal carcinoma in situ and intraductal papilloma with 23.1, 21.1 and 17.1%, respectively.

CONCLUSIONS:

Breast cancer remains a public health problem in Mexico and worldwide. Although more and better screening programmes are becoming available, this has brought with it other problems, such as premalignant or high-risk carcinogenic lesions, which have increased in incidence.

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