Do site and type of metastasis in breast cancer show a changing pattern with increased age? A cross comparison of clinicopathological characteristics between age groups

Abstract Background In here, we evaluated pattern of metastasis and cross-compared clinicopathological features between different age groups with breast cancer (BC). Methods This study was conducted in the Shiraz Breast Cancer Registry (largest BC registry in Iran). Patients were classified as  60 years old (group 3). The three age groups were compared regarding clinical and baseline characteristics. Results Overall, 564 individuals entered group 1, 4519 group 2, and 670 group 3. Group 1 had lower rates of tumor necrosis (p  60 years old had more lung metastasis (33 vs. 12.6 and 6.7% for groups 2 and 1, respectively) (p < 0.001). Younger groups had more < 5-year recurrence (16.3, 11.7, and 8.9%, for groups 1, 2, and 3, respectively) (p = 0.023). Conclusion Pattern and site of recurrence changes according to age in BC. This brings up the question whether age is an independent predictor of organ of metastasis or is site of metastasis the result of other clinicopathological determinants which differ between age groups