Loco-regional recurrences after mastectomy in breast cancer: prognostic factors and implications for postoperative irradiation.

Abstract

Potential risk factors including DNA flow cytometric-derived parameters predicting loco-regional recurrence (LRR) in early breast cancer were investigated. This study included 608 patients treated by modified radical mastectomy between 1982 and 1987. Recommendations regarding local treatment as well as adjuvant systemic therapy did not change during this period. Patients treated by adjuvant chemotherapy were randomized to receive additional medroxyprogesterone acetate (MPA) treatment. Only 59 (10%) patients received postoperative irradiation (XRT) to the chest wall and/or axillary lymph nodes; another 121 (20%) patients received XRT to the internal mammary nodes because of centromedially located tumours. Patients were followed for a median period of 7.5 years. The event-free survival at 10 years was 50%. The cumulative incidence rate of LRR at 10 years was 18% (n = 93), either with (n = 30) or without (n = 63) concurrent distant metastases. The chest wall, regional lymph nodes or both were involved in 41 (44%), 38 (41%) and 12 (13%) patients, respectively. Multivariate analysis according to the Cox model revealed two factors associated with LRR, i.e. pT (P < 0.05) and nodal status (P < 0.05). In node-positive patients extracapsular tumour extension (ECE) and pT were independent risk factors. DNA ploidy and S-phase fraction did not yield additional information. Based on pT, nodal status and extracapsular extension of tumour growth a high risk (> 10%) and low risk (< 10%) group for LRR could be identified. Results indicate that T-stage and nodal status, combined with ECE, may help to identify patients at risk for loco-regional recurrence, whereas DNA flow cytometry does not.