In this study, PEG-Intron(Trademark) will be administered subcutaneously once a week at low doses (0.3 microgram per kilogram of body weight) for a 4-week cycle. The cycles will be repeated indefinitely until progression of disease or serious side effects develop. For less severe effects, the dose will be lowered and the patient may remain in the study. For more severe effects, the dose will be discontinued. Patients in the study may receive supportive medication but may not receive other forms of chemotherapy.