Tumour size and vascular invasion predict distant metastasis in stage I breast cancer. Grade distinguishes early and late metastasis

Background: Recent Dutch guidelines recommend adjuvant systemic treatment (AST) for women with high grade stage I breast carcinoma greater than or equal to1 cm. High grade is defined as Bloom and Richardson grade 3 (B&R3), Nottingham modification, or mitotic activity (MAI) greater than or equal to 10/1.59 mm(2). Aims: To investigate the validity of these histological prognostic factors as the exclusive defining criteria. Materials/methods: Fifty patients with stage I breast carcinoma who developed distant metastases and 50 matched controls without metastasis were studied; none had received AST. Results: Cases more often had tumours greater than or equal to1 cm (p = 0,019), B&R3 tumours (p = 0.059), grade 3 nuclei (p = 0.005), and vascular invasion (p = 0.007). No differences were found for MAI greater than or equal to 10 (p = 0.46). In multivariate analysis, the only significant variables were vascular invasion and tumour size ( odds ratios: 8.21 and 5.35, respectively). In a separate analysis, the 50 cases were divided into 25 patients with early and 25 with late metastasis. Those with early metastasis more often had B&R3 tumours (p = 0.009) and grade 3 nuclei (p = 0.006). No differences were found for tumours greater than or equal to 1 cm, vessel invasion, or MAI greater than or equal to 10. Using the present Dutch guidelines for AST, based on B&R3, 20 cases and 11 controls would have received AST. Based on MAI greater than or equal to 10, 14 cases and 11 controls would have received AST. Conclusions: Tumour size and vessel invasion are the best prognostic factors for disease free survival in patients with stage I breast cancer. Dutch selection criteria for AST for these patients need to be improved. Some prognostic factors are time dependent, making their use as selection criteria for AST more complicated.