Adverse drug reactions are appreciably harmful or unpleasant reactions resulting from an intervention related to the use of medical products, which predicts hazard from future administration and warrants prevention or specific treatment, or alteration of the dosage regimen, or withdrawal of the product. Given medical case reports extracted from MEDLINE, the task is to classify whether the case report mentions the presence of any adverse drug reaction. Classify your answers into non-adverse drug event and adverse drug event.
Q: Our experience of this case led us to conclude that: patients with pulmonary metastases may develop bilateral and/or recurrent pneumothoraces following chemotherapy; computed tomography scan is essential for defining the cause of SSP; and closed chest tube drainage remains the therapy of choice, while chemical pleurodesis may also be used to prevent recidivant SSP.
A: 
non-adverse drug event