Remitting seronegative symmetrical synovitis with pitting edema (RS3PE) syndrome develops in patients with various underlying diseases. The involvement of vascular endothelial growth factor in the development of this syndrome has been suggested and malignant disease could be one of the underlying diseases of RS3PE syndrome. This syndrome is interpreted as one of the paraneoplastic syndromes that often have a poor prognosis. There have been few reports of lung cancer patients who developed RS3PE syndrome, and the prognosis of these patients has been rarely discussed. The present case report describes a very elderly lung cancer patient with RS3PE syndrome. We believe he is the oldest patient with advanced lung cancer to have developed RS3PE syndrome. Edema of the dorsum of both hands disappeared by one month after the start of first-line chemotherapy. The relatively long disease control period of the first and later lines of chemotherapy led to a long-term survival of 45 months. The existence of a patient with such a slow clinical course should be considered valuable for future research. It is important to continue optimal treatment even in elderly patients with RS3PE syndrome, one of the paraneoplastic syndromes.