[Early menarche as a risk factor of breast cancer]. / Menarquia temprana como factor de riesgo de cáncer de mama.

BACKGROUND: Most of the information in medical literature report diverse factors of breast cancer, which are related to the reproductive life of the woman. It is mentioned that menarche before the 12 years elevates the relative risk of this disease, in comparison with its appearance after the 13 years. OBJECTIVE: To determine if early menarche is a risk factor associated to breast cancer. MATERIAL AND METHODS: This retrospective, observational and descriptive study included 162 women with breast cancer from a 3 years period (2002-2004), in the Juarez Hospital of Mexico. In addition other well known risk factors for breast cancer were evaluated. The statistical analysis was made with the software program SPSS; the descriptive analysis was made by means of summary of statistics, histograms, box and bar charts. RESULTS: Early menarche doesn't have correlation with breast cancer nor with the appearance of the disease in early ages; it was present in the 12.3% (n = 20) of the patients; the menarche initiated between 12 and 13 years in 64.4% (n = 104.3) of the cases. The average age at the time of the diagnosis of breast cancer in the early menarche group was of 55 years and for the group in general of 47.6 years. The factor that seems to be related to breast cancer is overweight and obesity with 54.26 and 17.11% respectively, with an average body mass index of 27.7 kg/m2. CONCLUSIONS: There was not a correlation between early menarche as risk factor for breast cancer neither between the reproductive risk factors considered habitual and increased risk of breast cancer. Overweight and obesity seem to be related to the appearance of the disease, reason why it is required to investigate this with different random control groups in the country. We propose to study other factors that may be implicated in the genesis of breast cancer such as inflammatory factors, similar insulin growth factors and hyperinsulinism.