br Patients with missing information were excluded All patie
Patients with missing information were excluded. All patients were followed up, and their status was checked from their medical records. The follow-up period was managed by regular visits with physical examinations every 3 months during the first 2 years, every 6 months from years 3e5, and annually thereafter. Annual mammography with ultrasound was performed. For cases of local, regional or distant relapse suspicion in the CT scan, PET/CT scans or MRI was used. For BRCA K 252a holders, mammography, ultra-sonography and breast MRI was alternated every six months.
Overall survival (OS) and disease-free survival (DFS) were
calculated from the date of surgery until the date of death and the diagnosis of the first locoregional or systemic recurrence, respec-tively. In cases of incomplete events, OS and DFS were calculated for the entire investigated period until the last visit. Survival analyses were performed using the Kaplan-Meier method. The comparison between survival functions for different strata was assessed with log-rank statistics. Qualitative variables are expressed as a number and percentage, and quantitative variables are expressed as the median with minimum and maximum values. For the comparison of qualitative data, a chi-square test or Fisher's exact test was applied. Asymmetric numerical data were analysed using a Mann-Whitney test. Statistical significance was confirmed when P values were <0.05. Data analysis was performed using Statistica 13.4 (TIBCO Software Inc., Palo Alto, CA) and PAST version 1.86b .
During the investigation period, a total of 420 patients were assigned to the VYWBC group, and 390 patients were assigned to the YWBC group. Patients with missing information or those who were lost to follow-up were excluded. In total, we analysed data from 297 patients in the VYWBC group and 301 patients in the YWBC group. The median follow-up period was 69 months (range, 1e198 months) for the VYWBC group and 79 months (range, 1e170 months) for the YWBC group. The general characteristics of the two groups are presented in Table 1. Significant differences in the clinical characteristics were observed based on breast cancer sub-type (P ¼ 0.00008). The proportion of TN patients was higher in the VYWBC group than in the YWBC group. The proportion of luminal A type tumours was significantly higher than the luminal B type tu-mours in the YWBC group compared to the VYWBC group (Table 1). Significant differences in ER % (P < 0.000001), PR % (P < 0.000001), HER2 status (P ¼ 0.017) and Ki67 value (P < 0.000001) were observed between the two groups (Fig. 1) (Table 1). Significant differences only in the frequency of chemotherapy and endocrine therapy were observed (Table 2).
The YWBC group exhibited significantly better OS rates than did the VYWBC group (P ¼ 0.00005; log-rank) (Fig. 2). The BRCA 1/2 mutation holders did not exhibit significantly worse OS or DFS rates than those with negative results (P ¼ 0.749; log-rank) (Fig. 3).The YWBC group exhibited significantly better DFS rates than did the VYWBC group (P ¼ 0.00004; log-rank) (Fig. 4).
Compared to young breast cancer patients, very young breast cancer patients have poorer outcomes, which are in part attributed to more aggressive tumours and less favourable tumour subtypes . The current study showed a significantly higher mortality rate among women 35 years of age compared with women 36e45 years of age. Very young women in our study were not diagnosed with more advanced pT and pN disease compared with young women, but the frequency of distant metastasises was significantly higher in the younger group. According to a Danish study designed by Kroman et al. , where data from 10356 premenopausal women with breast cancer were analysed, the frequency of the pT1 category was lower in women aged under35 years than in women aged 35e45 years (49.7% vs. 54.7%), and the frequency of the pT2 category was higher in the younger group (38.1% vs. 34.3%). In our study, the rates of pT1 and pT2 categories in VYWBC vs. YWBC were