Abstract P3-07-13: Importance of socioeconomic status in relation to breast cancer risk and prognostic factors in Argentina.
Authors: Croce MV , Demichelis SO , Cermignani L , Zwenger A , Segal-Eiras A , Giacomi N 
Published: August 2014

In Argentina, there are no studies evaluating neither breast cancer screening nor risk and prognostic factors in relation to socioeconomic status among women in metropolitan areas. Taking into account that Argentina presents social and economical disparities and that there is a mixture of features of both developed and developing societies, it is interesting to compare prognostic and risk factors in disadvantaged and advantaged women as it would clarify the influence of socioeconomic factors in breast cancer biology. The purpose of this study was to compare risk and prognostic factors of invasive breast cancer in two different Argentine populations. Study participants and data collection. A total of 625 women who had a histologically confirmed diagnosis of invasive primary breast cancer were included; 270 patients belonged to a private clinic of the city of La Plata (province of Buenos Aires) belonging to an Advantaged Population (AP) and 355 patients belonged to a public hospital of the city of Neuquén (province of Neuquén, Patagonia) belonging to a Disadvantaged Population (DP). Women of these geographical regions and first diagnosed with invasive primary breast carcinoma from 2002 until 2007 were eligible as cases. There were no racial or ethnic differences between the two groups of women; all of them were born in Argentina. Risk factors included age at diagnosis, menarche and menopause status, breastfeeding and parity, while prognostic factors were: disease stage, number of metastatic lymph nodes, tumor size, histological and nuclear grade, vascular invasion, ER, PR, and Her2neu statuses.

Methods: Statistical analysis included frequency analysis and ANOVA (p &lt; 0.05).

Results: A remarkable difference between the two populations was found: the age at diagnosis was significantly lower in DP than in AP: 63% of DP versus 44% of AP was &lt;55 years old. AP stage III was observed at X = 49 years old versus DP at X = 54 years old; cutaneous and/or thoracic wall invasion was found at diagnosis in 15.4% of DP, while it was absent in all APs. Both groups showed advanced stages in younger patients. In general, tumor size versus age showed a negative relationship (p &lt; 0.04); this observation was only significant for AP (p &lt; 0.02). ER, PR expression, and Her2neu status presented differences between the two populations. Percentage of AP patients with positive ER were 78.8%, positive PR: 79.5%; while Her2-neu positive status was found in 5.3%. In the case of DP patients, positive percentages were: ER: 66.3%, PR: 51.2%; and finally Her2-neu: 38.8%. Histological and nuclear grade DP compared to AP were significantly higher, while vascular and lymphatic invasion showed the inverse DP: 30% versus AP: 18%, p &lt; 0.01. Taking into account the number of children, significant differences between groups were found: DP, 2.8+/−0.11 while AP, 1.9+/−0.13 (media +/− standard error). In general, it was observed that patients who had breastfed presented lower number of metastatic lymph nodes than those who had not.

Conclusions: Patients belonging to these two different geographical regions constitute two different populations. Breastfeeding and number of children, considered in relation to socio-economic features, are important risk factors of invasive breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-07-13.