Modeling effective tumor burden of primary lesion and metastatic lymph node in breast cancer patients from the SEER database.

Background: Characterizing the role of the primary tumor and axillary lymph nodes (ALNs) in metastasis progression can provide a rational basis for effective local control and systemic treatments.

Methods: We employed data from the Surveillance, Epidemiology, and End Results (SEER) database to perform survival analysis and modeling to estimate breast cancer (BC) progression in both untreated and treated patients. Effective tumor burden was defined as the number of cancer cells that can lead to distant metastasis. Quantified analysis was conducted for primary lesion and metastatic nodes, respectively. A tumor growth model was built based on mathematical modeling: . In this model, the parameters "m" and "n" represent the contributions of the primary lesion and metastatic lymph nodes (LNs) to distant metastasis, respectively.

Results: We found that both the primary lesion and the metastatic LNs contribute to the effective tumor burden. Through fitting the built tumor growth model, "m" in treated groups was determined to be 1, and "n" was determined to be 1.5; while in the untreated group, "m" was determined to be 1, and "n" was 0.15, which was 10 times smaller than in treated groups.

Conclusions: Our study revealed that the prognostic value of the anatomic stage in BC progression varied in different historical periods, due to the development of oncological treatments. While tumor size was a significant prognostic factor in both untreated and treated patients, the prognostic value of nodal status was only significant in patients who received locoregional treatment and systemic treatment.