Risk factors of invasive ductal breast carcinoma in elderly (≥65 years) women. Retrospective study in a cohort of 299 postmenopausal patients who underwent curative surgery

Background: In patients with breast cancer (BC) a number of risk factors (RF) have been studied. Unfortunately, many RFs associated with BC cannot be changed. However, several observational trials showed that the use of oral contraceptive (OC) and hormone replacement therapy (HRT), together with familial and reproductive RFs, can be useful in active or passive prevention of BC. The aim of this retrospective study was to evaluate the weight of the main data obtained from patients’ medical history (MH) in a population of elderly (≥65 years) women with confirmed invasive BC. Materials and Methods: We retrospectively reviewed data regarding a series of 299 consecutive postmenopausal women (mean age, 62.3±9.1 years), who underwent curative surgery for pT1-2, N0-1 (stage I and IIA) invasive ductal breast carcinoma. Two Groups of patients were considered: elderly (≥64 years) patients (Group 1, N=93, median age 73, range 65-86 years), and younger (<65 years) patients (Group 2, N=206, median age 57, range 45-64 years). Odds ratio (OR) estimates and the associated 95% confidence interval (95%CI) were obtained. Ninety-eight (47.6%) and 64 (68.8%) patients, respectively, underwent dual-energy X-ray absorptiometry for studying bone density. Results: At univariate analysis, HRT (OR=5.62, 95%CI=3.21-9.87, p<0.001), OC use (OR=2.58, 95%CI=1.31-5.10, p=0.005), first childbearing >30 years (OR=3.00, 95%CI=1.13-8.00, p=0.02) were strong RFs in younger patients (Group 2), while BMI>25 (OR=1.81, 95%CI=1.02-3.20, p=0.04) was a weak RF in elderly patients (Group 1). As expected, the presence of osteopenia or osteoporosis (OR=0.46, 95%CI=0.24-0.88, p=0.02) represented a protective factor in Group 1. Other data obtained from patients’ MH, including family history of BC (p=0.79), no pregnancies (p=0.58) or breast-feeding (p=0.09), and history of benign breast diseases (p=0.43) did not differ significantly between Groups. At multivariate analysis, only HRT was an independent RF, and the area under the curve (ROC) was 0.68. Conclusions: In older (≥65 years) patients, most of whom (62.1% vs. 22.6%, χ2=31.1, p<0.001) had taken HRT, such as MH represents a significant RF for BC, and should be more carefully considered in the prevention campaigns.