In addition to residual tumor cells, surgery-induced inflammation significantly contributes to tumor recurrence and metastasis by recruiting polymorphonuclear neutrophils (PMNs) and promoting their involvement in tumor cell proliferation, invasion and immune evasion. Efficiently eliminating residual tumor cells while concurrently intervening in PMN function represents a promising approach for enhanced postoperative cancer treatment. Here, a chitosan/polyethylene oxide electrospun fibrous scaffold co-delivering celecoxib (CEL) and doxorubicin-loaded tumor cell-derived microparticles (DOX-MPs) is developed for postoperative in-situ treatment in breast cancer. This implant (CEL/DOX-MPs@CP) ensures prolonged drug retention and sustained release within the surgical tumor cavity. The released DOX-MPs effectively eliminate residual tumor cells, while the released CEL inhibits the function of inflammatory PMNs, suppressing their promotion of residual tumor cell proliferation, migration and invasion, as well as remodeling the tumor immune microenvironment. Importantly, the strategy is closely associated with interference in neutrophil extracellular trap (NET) released from inflammatory PMNs, leading to a substantial reduction in postoperative tumor recurrence and metastasis. Our results demonstrate that CEL/DOX-MPs@CP holds great promise as an implant to enhance the prognosis of breast cancer patients following surgery.