Impact of mammographic screening in staging, treatment and prognosis of breast cancer: Early assessment

Abstract

10537 Background: The use of breast cancer mammographic screening (MS) leads to early detection and has been shown to reduce the mortality rate and to increase the proportion of breast-conserving surgery. The aim of this study is to analyze the impact of mammography in the staging, treatment and prognosis of breast carcinoma. Methods: In 1993, a population-based mammographic screening among women aged from 45 to 70 years was introduced in the community of Valencia. We examined the effects of this MS program by the comparison of two populations. The first one included all the women with screen-detected invasive breast carcinoma between 1993 and 2002 in the community of Valencia. The second one was comprised of all the women with invasive breast carcinoma, diagnosed in the same period, aged 45–70, not attending the MS and treated at H. Clinico of Valencia. Results: Between January, 1993 and December, 2002, 2313 new invasive breast cancer patients were detected by the MS program in the community of Valencia, and 1349 women aged 45–70, not attending de MS were diagnosed with invasive breast carcinoma in H.Clinico of Valencia. The median follow-up period was 45.5 months for the screen-detected breast cancer and 51.9 months for not screen-detected patients. The screen-detected tumors had smaller pathological size (pT1 tumors 70.2% vs 40.5%, p < 0.0001), were more likely to have pathologically confirmed negative nodal status (66.4% vs 52.2%, p < 0.0001) and stage I disease (55.3% vs 26.1%, p < 0.0001). Breast-conserving surgery was performed in 50.4% of patients with screen-detected tumors and in 31.9% of women who had not undergone MS (p < 0.0001). The 5-year estimated survival was 95.5% (SE 0.57) for women with screen-detected breast cancer and 85.5% (SE 1.17) for those with not screen-detected tumors (p < 0.0001). Conclusions: Our data demonstrate a better prognosis in terms of 5-year survival in screen-detected breast cancer patients that may explain why breast carcinoma mortality rates have decreased in recent decades. These patients have also been found to have smaller tumors, a more favorable tumor stage and a higher proportion of breast-conserving surgery. No significant financial relationships to disclose.