Journal of Clinical Oncology vol:27 issue:18 pages:2931-2937
Purpose: To study the relation between the presence of axillary lymph node (LN) involvement and age in breast cancer.
Patients and methods: The breast cancer database of the University Hospitals Leuven contains complete data on 2.227 patients with early breast cancer consecutively treated between 2000 and 2005. A multivariate piecewise logistic regression model was used to analyze LN involvement in relation to age at diagnosis. A similar analysis was then performed on a large, independent, population-based database from the Eindhoven Cancer Registry to investigate whether the effects of the Leuven model could be replicated.
Results: We observed a piecewise effects of age. That is, women up to 70 years of age were less likely to have positive LNs with increasing age (odds ratio per 10-year increase, 0.87). In contrast, older women were more likely to have positive LNs with increasing age. However, for older women, the effect of age interacted with tumor size (P = .0044), suggesting that increasing age is associated with increased risk of LN involvement, mainly in small tumors. These findings were replicated in the Eindhoven Cancer Registry database.
Conclusion: Axillary LN involvement varies with age at diagnosis; its probability decreases with increasing age up to the age of approximately 70 years, but increases again thereafter. However, this increase is mainly seen in smaller tumors and suggests a different behavior of small breast cancers in older adult patients. We hypothesize that decreased immune defense mechanisms, related with aging, may play a role in earlier invasion into LNs.