The Benefit of Baseline Staging-Risk Assessment of Distant Breast Cancer Metastases by Tumor Stage.

Background: Despite recommendations of international societies, use of baseline staging in breast cancer varies considerably. We retrospectively analyzed the prevalence of metastases in each pTN stage to estimate the benefit of staging.

Patients And Methods: The prevalence of metastases at primary diagnosis (M1) and in the first year after diagnosis (M112) was determined in 2,906 patients.

Results: The prevalence of M1 was 0.95% [95% confidence interval (CI)=0.53-1.70%] in pT1pN0, 2.17% (95% CI=1.00-4.64) in pT1pN1 and 1.53% (95% CI=0.78-2.99%) in pT2pN0. The prevalence of M112 was 2.17% (95% CI=1.47-3.18%) in pT1pN0 and 3.25% in pathological stage IIA (upper confidence bound 5.14%). In pT2pN1 the prevalence of M1 and M112 was 3.49% (95% CI=1.96-6.14%) and 6.35% (95% CI=4.15-9.60%), respectively. Results for stage pT3pN0 and higher were inconclusive.

Conclusion: Baseline staging can be safely abandoned in pathological stage I and IIA. Individual decisions should be made for pT2pN1. Staging is recommended in stages of pT3pN0 or higher.