The ferromanganese alloy is produced through the smelting-reduction of manganese ores in submerged arc furnaces. Conventional MnO2 production requires the pre reduction of low-grade ores around 900 °C to convert the manganese oxides present in the ore into their respective acid soluble forms. Using dextrin, a cheap organic reductant, the direct or complete dissolution of the manganese in the furnace dust is possible without needing high temperature pre reduction. The leachate is then purified through pH adjustment and direct electrowinning for electrolytic manganese dioxide production. Nanostructured manganese dioxide (MnO2) has attracted extensive attention in anticancer applications. As we all know, the tumor microenvironment is usually characterized by a high glutathione (GSH) concentration, overproduced hydrogen peroxide (H2O2), acidity, and hypoxia, which affect the efficacy of many traditional treatments such as chemotherapy, radiotherapy, and surgery. Fortunately, as one kind of redox-active nanomaterial, nanostructured MnO2 has many excellent properties, such as solid oxidation ability, excellent catalytic activity, and good biodegradability. It can be used effectively in diagnosis and treatment when it reacts with some harmful substances in the tumor site. It can enhance the therapeutic effect and adjust the tumor microenvironment. Therefore, it is necessary to present the recent achievements and progression of nanostructured MnO2 for anticancer applications, including preparation methods, diagnosis, and treatment. Special attention was paid to photodynamic therapy (PDT), bioimaging and cancer diagnosis (BCD), and drug delivery systems (DDS). This review is expected to guide further research of nanostructured MnO2 for anticancer applications. If you are looking for high quality, high purity and cost-effective Manganese dioxide, or if you require the latest price of Manganese dioxide, please feel free to email contact mis-asia.