Table 3.
Comparison of clinicopathological characteristics between synchronous and metachronous bilateral breast cancer
| Characteristics | SBBC | MBBC |
|---|---|---|
| Incidence rate [55,56] | 0.7%-1.4% | 0.91%-2.5% |
| Average age [56] | 53.5 years old | 44 years old, Median interval for SPC: 67.9 months [57]1 |
| TNM2 staging [58] | Stage III accounts for 50.5% | T1 accounts for 68.9% |
| Imaging findings | Multifocality/Multicentricity [59] | Often accompanied by axillary lymph node enlargement [60] |
| Molecular subtype | ER+(60%-75%), HER-2 + 315%-20% [25, 61] | ER+(50%-65%), TNBC20%-25% [62] |
| Pathological type | Invasive ductal carcinoma(80%-90%) [63] | Invasive ductal carcinoma(75%-85%), the proportion of invasive pathology is higher in second cancers [8] |
| Histological grade | Mainly Grade 2(60.8%) [58] | The second cancer may be of a higher grade [64] |
| 5-year OS | 74.6%-82% [28, 65] | 63.2%-70%, if the interval is > 5 years, it increases to 75% [1, 66] |
1Mruthyunjayappa et al. analyzed 52 cases in a U.S. cohort and found that the median interval time for MBBC was 67.9 months
2TNM staging: The TNM staging system (Tumor, Node, Metastasis) classifies cancer progression based on primary tumor extent (T), lymph node involvement (N), and distant metastasis presence (M)
3HER-2 + indicates HER-2 expression++/+++, and FISH staining is positive