Clinical Characteristics and Features of Noninvasive Breast Cancer

Introduction. This article presents the study of 110 female patients diagnosed with stage 0 breast cancer conducted at the P. Hertsen Moscow Oncology Research Institute between 2023 and 2024. Materials and methods . By histological type, ductal carcinoma in situ (Tis, DCIS) predominated in 100/110 cases (90.9%), followed by Paget’s disease (Tis, Paget) in 7/110 (6.4%), and lobular carcinoma in situ (Tis, LCIS) in 3/110 (2.7%). Mastectomy was performed in 17 patients (15.5%), skin-sparing mastectomy with reconstruction in 44 (40%), and breast-conserving surgery in 49 (44.5%). Results . According to routine histological examination, progression of DCIS was identified in 42/110 patients (38.2%). Among them, stage I breast cancer was diagnosed in 33.6% and stage II in 4.5%. In routine morphological examination, positive resection margins (R1) were detected in 15 patients (13.6%). Discussion . Breast MRI in non-invasive breast cancer is an essential procedure for determining disease extent, assessing multifocality or multicentricity, and thus guiding the decision on breast-conserving surgery versus mastectomy. Another important issue is the need to evaluate sentinel lymph nodes in cases of non-invasive breast cancer. Conclusion . Local recurrences of breast cancer in the analyzed group were diagnosed in 2 patients (1.8 ± 1.6%). Progression of stage 0 breast cancer to higher stages, i.e., cTis → pT+, was observed in 42/110 patients (38.2%). Despite the extent of disease (mean size of carcinoma in situ was 42 mm), breastconserving surgery or nipple-/skin-sparing mastectomy with reconstruction were performed in 93% of cases. Thus, carcinoma in situ may progress to higher stages in about 40% of patients. The role of diagnostic methods in assessing breast cancer stage is therefore crucial for selecting an optimal surgical management.