Management of docetaxel-induced edema is important as severe edema may lead to discontinuation of chemotherapy. Patients with stage IV breast cancer (BC) treated with docetaxel have shown lower limb edema; however, details of its developmental and healing processes are unknown, and thus management strategies have not been established. The aim of this study was to investigate the characteristics of the development and healing process of docetaxel-induced lower limb edema in stage IV BC patients. This prospective observational study was conducted on patients with BC who were administered docetaxel between September 2020 and September 2021 at a National Hospital in Japan. Skin changes such as pitting test, circumference, along with ultrasound images and subjective symptom changes were evaluated. The progression of these changes was compared between patients with stage IV and non-stage IV disease. Five patients were enrolled in the study, of which two and one patients with stage IV and non-stage IV disease, respectively, developed lower limb edema. Early signs of lower limb edema were observed in ultrasound images, 15 cm below the peroneal head, before edema was confirmed by the pitting test and subjective symptoms. In patients with stage IV disease, edema worsened to Grade 3, and reduced four months after the end of drug administration. For patients with stage IV disease, care should be initiated from the time the early signs are observed using ultrasound and continued for up to four months after the end of docetaxel administration.