Early diagnosis of lung cancer still poses a major issue, with a large proportion of patients diagnosed at late stages. Therapeutic options and treatment remain limited in these patients. In most cases only palliative therapies are available to alleviate any severe symptoms. Endobronchial cryotherapy (EC) is one form of palliative treatment offered to patients with obstructive airway tumours. Although successful, the impact on circulating tumour cell (CTCs) spread has not been investigated in detail. This study recruited 20 patients awaiting EC treatment. Baseline and post EC blood samples were analysed for presence of CTCs. Results showed an increase in CTCs following EC in 75% of patients. Significant increases were noticeable in some cases. Although EC is a well-accepted modality of treatment to alleviate symptoms, it may lead to an increase in CTCs, which in turn may have implications for tumour issemination and metastatic spread.