演題番号 : P-413
Pneumothorax was not reported as a common adverse event of pazopanib (PZ). However, according to subsequent studies, the incidence might exceed it. The actual etiology of pneumothorax has not been elucidated, but was considered to be leak of air from degenerated tumor by PZ. In this study, we reviewed the experience of pneumothorax during PZ and proposed two different types of the pneumothorax caused by PZ.
Materials and methods
The pneumothorax patterns were defined as follows; 1. Peripheral type: The metastatic lesion is located around or attached to the visceral pleura. After the cavitation of the metastatic tumor, the pneumothorax occurred by the connection to the chest cavity and the ruptured cavity. Central type: The metastatic lesion is located at the central part of the lung. After the cavitation, the check valve or continuous air leakage to the cavity are generated. In the end, the high-pressured thin cavity ruptures and pneumothorax occurs. From 2014 to 2018, patients with metastatic soft-tissue tumors in lung and treated by PZ were analyzed. Then, the pneumothorax patterns were classified.
Total 12 patients were treated by PZ. The majority of the histology was UPS and the mean age of the patients was 44. Of these, 13 incidences of pneumothorax (4 patients) occurred as peripheral pattern and 2 incidences of pneumothorax (2 patients) occurred as central pattern. The severity of pneumothorax was small in 11 incidences large in 2 incidences in peripheral type; large in 2 incidences in central type. Time to first pneumothorax was 6 months (2 weeks to 20 months). Cavitation of the tumor preceded in all the pneumothorax cases.
As a response to PZ, cavitation of lung lesion occurs. Depending on the patterns of cavitation, 2 different types of pneumothorax pattern were observed. Peripheral type was more prevalent and milder than central type. Once the pneumothorax occurred, it sometimes repeated and intractable.