Risk factors for lung metastases from invasive ductal breast carcinoma. A case-control study at five-year follow-up in a population of women who underwent curative surgery

Background: Breast cancer (BC) accounts for about one-third of cases of cancer in women. BC occurs predominantly in elderly women, continue to be one of the most common causes of cancer death, and mainly metastasizes to the skeleton and lung. Although complete excision of primary tumor improves survival in patients with advanced metastatic disease, pulmonary metastasectomy plays a role in the management of patients. However, patients with small metastasis have a better overall survival, and thus the early detection of lung metastases (LM) is crucial. Indeed, in several studies, risk factors (RFs) such as age, stage of the disease, serum tumor markers, and other biological parameters obtained from pathological specimen, have been evaluated. The aim of this study was to analyze their role in differentiating patients at risk of having LMs among a cohort of women with BC. Patients and methods: We retrospectively reviewed data regarding a series of 348 women (median age 60 years, range 28-85) who underwent curative surgery for pT1-2, N0-1 (stage I and IIA) invasive ductal breast carcinoma. During five-year follow-up, 15 (4.3%) patients developed LMs (cases), and 39 (11.2%) other type of cancer relapse, while 294 (84.5%) were disease-free (controls). The followings parameters were considered: age of the patients, size of the tumor (T), axillary lymph node (AN) status (N), estrogen (ER) and progesterone (PR) receptor negativity, human epidermal growth factor receptor 2 (HER2) and nuclear antigen Ki67 overexpression, adjuvant chemotherapy. Odds ratio (OR) estimates and the associated 95% confidence interval (CI) were obtained, and the significance level was set at p<0.01. Results: Age<50 (OR=4.55, 95%CI 1.58-13.05, p=0.005), and N1 status (OR=8.03, 95%CI 2.48-25.98, p=0.0002) were statistically significant RFs for LM from BC. Tumor size>2 cm (T2) (OR=2.90, 95% CI 1.02-8.27, p=0.041), and ER negativity (OR=3.51, 95% CI 1.21-10.17, p=0.018) were weak RFs, while PR negativity (OR=2.01, 95% CI 0.70-5.73, p=0.14), HER2 (OR=1.48, 95% CI 0.49-4.49, p=0.32) and Ki67 (OR=1.72, 95% CI 0.59-4.99, p=0.23) overexpression, and no chemotherapy administration (OR=1.06, 95% CI 0.35-3.20, p=0.55) were independent of LMs onset.