Pneumothorax in lung metastasis of advanced soft tissue sarcoma patients treated with oral pazopanib.

Aim: Data on occurrence of pneumothorax after the use of oral pazopanib in advanced soft tissue sarcoma (STS) with lung metastases are scarce in literature. We aimed to evaluate those in our patients.

Methods: This was a single center retrospective study of incidence of pneumothorax in patients with lung metastases in advanced STS treated with oral pazopanib between July, 2016 and December, 2020. Patients were treated with pazopanib usually from 2 nd line onwards with a dose ranging from 400 mg to 800 mg once daily.

Results: Total of 34 patients with lung metastasis in a setting of advanced STS were treated with oral pazopanib during the study period. The setting of pazopanib use was 2 nd line in four and 1 st line in one of them. The starting dose was 600 mg once daily in three patients, 400 mg OD in one patient, and 800 mg OD in one patient. Five patients developed pneumothorax with duration on pazopanib of 6, 7, 24, 6, and 2.5 months, respectively. Three patients had symptoms and required chest tube drainage. None of them were smokers or had any other underlying lung disease. The disease response of those patients was stable disease in four and partial response in one during treatment with pazopanib. One patient had a rechallenge with further pazopanib course without any recurrence of pneumothorax.

Conclusions: Pneumothorax is a rare pulmonary complication after pazopanib use in patients with lung metastasis. Clinicians should be aware of this rare complication as literature is scarce. Rechallenge with pazopanib is feasible after pneumothorax.