Study of the problem of multiple primary malignant neoplasms (MPMNs) becomes more important and significant in modern clinical oncology. MPMN is a varied group of independent tumors of varying origin located in one or several organs. Due to introduction of single-use elastomeric microinfusion pumps into the clinical practice, continuous cyclical drug outpatient and in-hospital treatment of oncological patients with MPMNs can be performed. Significant successes of specific therapy led to increased lifespan of patients with MPMNs. Prolonged administration of drugs using infusion pump with set velocity allows to deliver cytostatics into the patient’s body in strictly controlled amounts. The article presents 2 clinical cases of effective antitumor treatment of patients with MPMNs using infusion pum