Disclosed is an intralymphatic delivery method for treating lymphatic cancer using hyaluronan nanoparticles. These nanoparticles include a hyaluronic acid derivative and a platinum compound. The hyaluronan derivative includes hyaluronic acid, modified histidine and optionally one or more of a polymer or a C4-C20 alkyl. The hyaluronic acid derivative may include linking group(s) that connect the polymer or the C4-C20 alkyl to the hyaluronic acid. The platinum compound includes dichloro(1,2-diaminocyclohexane) platinum (DACHPt), cisplatin and oxaliplatin. This intralymphatic delivery method offers significant advantages for the use of platinum medicines in treating lymphatic cancer.