A long-term retrospective comparative study of the oncological outcomes of 598 very young (≤35 years) and young (36–45 years) breast cancer patients

Background Breast cancer diagnosed in very young women (VYWBC; ≤35 years) and young women (YWBC; 36–45 years) tends to be heterogeneous. The current study aimed to compare the clinicopathological characteristics and long-term clinical outcomes between YWBC and VYWBC subgroups. Patients and methods The institutional prospectively led database was retrospectively analysed from 2000 to 2014 at the National Institute of Oncology, Hungary. A total of 297 patients were assigned to the VYWBC group, and 301 patients were assigned to the YWBC group. Results The median follow-up period was 69 months for the VYWBC group and 79 months for the YWBC group. Significant differences were observed based on breast cancer subtype. The proportion of Triple-negative and ER-negative patients was higher in the VYWBC group than in the YWBC group (P = 0.00008). The incidence of distant metastasis was significantly higher in the VYWBC group (P = 0.01). Significant differences in the frequency of chemotherapy (P = 0.049) and endocrine therapy (P = 0.037) were observed between the two groups. The YWBC group exhibited significantly better overall survival (OS) and disease-free survival (DFS) rates than did the VYWBC group (P = 0.00005 and P = 0.00004, respectively). Conclusion Breast cancers in VYWBC are biologically different from those in YWBC and tend to be more aggressive. Younger age was associated with worse OS and DFS. Young women with breast cancer should be subgrouped into VYWBC and YWBC populations, and these subgroups should be targeted by specialized clinical trials and further investigations.