The study was designed to evaluate a treatment-tradeoff method for its potential in helping lung cancer patients make treatment decisions. A treatment-tradeoff interview was conducted to determine how patients weighed potential survival benefits against the potential toxicities of different treatment options: 1) low-dose versus high-dose radiotherapy, and 2) high-dose radiotherapy versus combination chemo-radiotherapy. Fifty-six patients who had experienced cancer and 20 clinic staff participated; twenty of these participants repeated the interview in an assessment of response consistency. The treatment-tradeoff method proved feasible: all staff and 53 of the 56 patients were able to complete the process. A wide range of threshold scores across participants was observed for both tradeoffs. Sixty percent of the patients would accept the more toxic combination therapy over high-dose radiotherapy if the former offered a 10% absolute improvement in three-year survival. The method also proved reliable: test-retest correlations were high (tau ranged from 0.7 to 0.87 and r from 0.82 to 0.94) and test-retest mean score differences were low (1.3-4.2). The most clinically useful measure of consistency was a "preference consistency" index, which revealed that most patients declared the same treatment preference at test and retest. The authors conclude that, while there is great interindividual variability in willingness to accept aggressive treatments for lung cancer, patients' values can be consistently elicited with the tradeoff method. The method has potential for clinical application in decision making and for health-care policy development.