Louro, Javier, Román, Marta, Posso, Margarita, Comerma, Laura, Vidal, Carmen, Saladié, Francina, Alcantara, Rodrigo, Sanchez, Mar, Quintana, M. Jesús, del Riego, Javier, Ferrer, Joana, Peñalva, Lupe, Bargalló, Xavier, Prieto, Miguel, Sala, Maria, Castells, Xavier, Universitat Autònoma de Barcelona, [Louro J] Hospital Del Mar Medical Research Institute (IMM), Barcelona, Spain. Research Network on Health Services in Chronic Diseases (REDISSEC), Barcelona, Spain. Servei d’Epidemiologia i Avaluació, Hospital del Mar, Barcelona, Spain. European Higher Education Area (EHEA) Doctoral Programme in Methodology of Biomedical Research and Public Health in Department of Pediatrics, Obstetrics and Gynecology, Preventive Medicine and Public Health, Universitat Autònoma de Barcelona (UAB), Barcelona, Spain. [Román M, Posso M] Hospital del Mar Medical Research Institute (IMM), Barcelona, Spain. Research Network on Health Services in Chronic Diseases (REDISSEC), Barcelona, Spain. Servei d’Epidemiologia i Avaluació, Hospital del Mar, Barcelona, Spain. [Comerma L] Servei de Patologia, Hospital del Mar, Barcelona, Spain. [Vidal C] Institut Català d’Oncologia (ICO), Barcelona, Spain. [Saladié F] Cancer Epidemiology and Prevention Service, Hospital Universitari Sant Joan de Reus, Institut d’Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Reus, Spain. [Alcándara R] Servei de Diagnòstic per la Imatge, Hospital del Mar, Barcelona, Spain. [Sánchez M] Direction General of Public Health, Cantabria, Spain. [Quintana MJ] Department of Clinical Epidemiology and Public Health, University Hospital de La Santa Creu i Sant Pau, IIB Sant Pau, Barcelona, Spain. CIBER of Epidemiology and Public Health (CIBERESP), Spain. [Del Riego J] Women’s Imaging, Department of Radiology, UDIAT Centre Diagnòstic, Parc Taulí Hospital Universitari, Sabadell, Spain. [Ferrer J] Radiology Department, Hospital de Santa Caterina, Institut d’Assistència Sanitària (IAS), Salt, Spain, and Institut d'Assistència Sanitària
Introduction We aimed to assess differences in breast cancer risk across benign breast disease diagnosed at prevalent or incident screens. Materials and methods We conducted a retrospective cohort study with data from 629,087 women participating in a long-standing population-based breast cancer screening program in Spain. Each benign breast disease was classified as non-proliferative, proliferative without atypia, or proliferative with atypia, and whether it was diagnosed in a prevalent or incident screen. We used partly conditional Cox hazard regression to estimate the adjusted hazard ratios of the risk of breast cancer. Results Compared with women without benign breast disease, the risk of breast cancer was significantly higher (p-value = 0.005) in women with benign breast disease diagnosed in an incident screen (aHR, 2.67; 95%CI: 2.24–3.19) than in those with benign breast disease diagnosed in a prevalent screen (aHR, 1.87; 95%CI: 1.57–2.24). The highest risk was found in women with a proliferative benign breast disease with atypia (aHR, 4.35; 95%CI: 2.09–9.08, and 3.35; 95%CI: 1.51–7.40 for those diagnosed at incident and prevalent screens, respectively), while the lowest was found in women with non-proliferative benign breast disease (aHR, 2.39; 95%CI: 1.95–2.93, and 1.63; 95%CI: 1.32–2.02 for those diagnosed at incident and prevalent screens, respectively). Conclusion Our study showed that the risk of breast cancer conferred by a benign breast disease differed according to type of screen (prevalent or incident). To our knowledge, this is the first study to analyse the impact of the screening type on benign breast disease prognosis., Highlights • Breast cancer risk after a benign breast disease varied with the screening type. • Incident benign breast disease had a higher breast cancer risk than prevalent. • The risk remained increased regardless of benign breast disease subtype.