Are There Breast Cancer Patients with Node-Negative Small Tumours, Who Do Not Benefit from Adjuvant Systemic Therapy?

To identify subgroups of patients with pT1 pN0 breast cancer (BC) who might not profit from adjuvant systemic therapy (AST).

Data of 3,774 pT1 pN0 BC patients from 17 certified BC centres within the BRENDA study group were collected between 1992 and 2008 and retrospectively analysed. Uni- and multivariate analyses were performed using Kaplan-Meier methods and Cox regression models.

279 (7.4%) of the pT1 pN0 BC patients were T1a, 944 (25.0%) were T1b and 2,551 (67.6%) were T1c. There was no significant difference (p > 0.1) in recurrence-free survival (RFS)/overall survival (OAS) between patients with pT1a, pT1b, and T1c. Patients receiving any type of AST had a better outcome compared to women without AST after adjusting for age, tumour size, and intrinsic subtypes (RFS: p < 0.001; OAS: p < 0.001). AST was the most important prognostic parameter for RFS followed by intrinsic subtypes and age.

Patients with pT1 pN0 BC profit from AST independently of molecular subtypes, tumour size, age or comorbidity, with 5-year RFS of more than 95%. The correct definition of subgroups of patients who do not need AST is still an open question.