Clinical and morphological parameters and assessment of disease prognosis in patients with breast cancer under 40 years of age

Background: Over 10 years from 2013 to 2023, the number of new cases of breast cancer (BC) among women under the age of 40 increased in the Krasnoyarsk region. The increase in new cases was 63.9 % (from 83 cases in 2013 to 136 cases in 2023). Aim: The analysis of clinical and morphological parameters and assessment of the prognosis of the disease in young women under 40 years old with breast cancer in the Krasnoyarsk region. Materials and methods: We performed a retrospective analysis of data from the Population Cancer Registry, the TFOMS Oncology Registry and MIS qMS on breast cancer patients under 40 years diagnosed in the Krasnoyarsk region for the period of 2013–2023. Statistical analysis was carried out using Microsoft Excel, Statistica 12 and StatTech 4.0.6 software products. Survival analysis was performed using Kaplan-Meier curves, and the log-rank test was used to evaluate differences in survival. Outcomes of interest were event-free survival (EFS) and overall survival (OS). EFS was defined as the time period from diagnosis to disease relapse, disease progression, or death, whichever occurred first. OS was defined as the time period from diagnosis until final analysis (3 / 31 / 2024) or death, whichever occurred first. The significance level of the test was considered statistically significant at p < 0.05. Results: In the region, women with breast cancer were detected in the early stages predominately (73.0 %), mostly invasive carcinomas by morphological type (89.6 %) and HR(+) Her2(–) molecular genetic subtype (50.6) %. Five-year survival rate during the study period increased by 48.1 %, one-year mortality decreased by 81.7 %. OS and EFS for patients with advanced breast cancer are statistically significantly lower. There was no correlation between OS and EFS by tumor subtype. Lower OS rates in patients with HR(–) Her2(–). Lower EFS rates in patients with HR(+) Her2(–). Conclusions: The results of the analysis to identify the clinical features of the course and assess the prognosis of the disease in patients with breast cancer under the age of 40 years indicate the need to revise the age for starting screening studies aimed at detecting breast cancer in the early stages.