Capillary leak syndrome: terra incognita and a dangerous complication of anticancer therapy

This review focuses on capillary leak syndrome (CLS) as a potential complication of anticancer therapy, its pathogenesis, and possible diagnostic and treatment options. Over the past decade, cardio-oncology, an interdisciplinary field of medicine, has been rapidly developing. Its aim is to assess the underlying cardiac risk in patients with malignant neoplasms and, on the one hand, to manage the complications of anticancer therapy. While the term “cardiotoxicity” has long been known, the concept of “vasculotoxicity” remains somewhat terra incognita for the vast majority of oncologists. One manifestation of vasculotoxicity can be capillary leak syndrome, or CLS. In 1960, the first clinical case of recurrent edema syndrome, combined with manifestations of hypovolemic shock, was described. In the development of CLS, the leading role is assigned to the disruption of endothelial dysfunction, associated immune reactions and a number of inflammatory mediators. Cases of primary CLS are rare, while secondary one is observed in a wide range of conditions, including hematological malignancies, dermatological and systemic diseases, infections, the use of certain medications or exposure to toxins, and postoperative and traumatic events. A total of 243 drugs have been identified that are potentially associated with at least one case of vascular endothelial dysfunction. 560 individual safety reports were compiled for 52 of the 243 drugs. Of these 52 drugs, 45 (86,5 %) were antineoplastic and immunomodulatory agents. Because a large number of CLS cases are associated with antineoplastic treatment, special attention to this serious complication should be paid by oncologists, hematologists, and physicians of all specialties involved in the monitoring of these patients.