The spatial degrees of freedom will be sacrificed to perform the precoding-based interference management (IM) for the cell-edge user (CEU) in a massive multiple-input and multiple-output enabled irregular network. It is desired to evaluate the impact of the precoding-based IM on the performance of both the cell-centre user (CCU) and CEU, which leads to a consideration of the balance between the CEU performance enhancement and the CCU tolerable performance degradation. Thus the separate analysis of CEU and CCU performance under the precoding-based IM is imperative. To facilitate the analysis, the authors propose an approximate distribution of the CEU numbers with a flexible CEU definition in a single-tier irregular network. With this distribution, the upper bound of the success probability of the typical CEU using the precoding-based IM is analysed. Also, a lower bound of the success probability of the typical CCU is given. Moreover, the impact of the cell-edge area on the success probability of both the CCU and CEU is discussed. It is found that the success probability of both the CCU and CEU decreases with the enlarged cell-edge area in the case of the high density of users and small density of base stations. Nevertheless, the tendency of the success probability versus the cell-edge area becomes diverse in the dense network or sparse user scenario.