OBJECTIVE More than 80% of patients with lung cancer are unsuitable for curative surgical treatment. Palliative relief of symptoms, often caused by airway obstruction, is very important. Endobronchial cryosurgery is used for destruction of intraluminal tumors. This study analyzes the effects of cryosurgery on patients with obstructive endobronchial carcinoma. METHODS Retrospective analysis of data extracted from a prospective computerized database. METHODS Tertiary referral thoracic surgical center. METHODS Data of the 172 patients who underwent at least two sessions of endobronchial cryosurgery (group A) were compared with 157 patients who underwent one session of cryosurgery (group B) for malignant primary or metastatic obstructive lung carcinoma over a 5-year period. METHODS Endobronchial cryosurgery is performed under general anesthesia. A nitrous oxide cryoprobe is inserted through a rigid bronchoscope. The probe achieves a temperature of - 70 degrees C at its tip and is applied to the tumor for two 3-min periods. Statistical analysis assessed the effects of cryosurgery on symptoms, lung function, Karnofsky performance score, and survival. RESULTS Symptoms of dyspnea, cough, and hemoptysis were significantly reduced in both groups after cryosurgery (p < 0.001), although group A benefited more than group B. Lung function test results improved significantly in group A. The mean Karnofsky performance score (+/- SD) increased from 67 +/- 9 to 74 +/- 10 (group A) and from 67 +/- 10 to 73 +/- 11 (group B). The mean survival was 15 months (median, 11 months) for group A and 8.3 months (median, 6 months) for group B (p = 0.006). Univariate regression analysis showed that no particular patient or tumor characteristic was associated with reduction of symptoms. Patients who had cryosurgery and external beam radiotherapy showed longer survival (p < 0.01). Females and patients with stage IIIa and IIIb tumors achieved significantly improved Karnofsky scores (p < 0.02). Female sex was also a factor for increase in FEV at 1 min (p = 0.003) and FVC (p < 0.001). CONCLUSIONS Cryosurgery is a safe method for palliation of endobronchial malignancies causing airway obstruction. Statistical analysis showed improvement of dyspnea, cough, and hemoptysis. Cryosurgery can be considered in patients with inoperable obstructive endobronchial carcinoma.