The role of palliative irradiation was analysed in 55 patients with liver metastases from colorectal (n = 35), breast (n = 10) and lung cancer (n = 10), treated between January 1982 and June 1992 with irradiation doses more than 10 Gy. In 47 patients irradiation alone was done. The great majority of patients were treated because of pain (n = 21) or cholestasis (n = 22). In 29 patients the disease involved not only the liver, but was disseminated. A mean dose of 23.8 Gy was delivered, with daily fractions of 1.5 (n = 30), 1.8 (n = 1) or 2 Gy (n = 16). Complete and near complete pain relief was obtained in six (28.6%) and nine (42.9%) patients. Normalized and near normalized values of bilirubin serum levels were obtained in five (22.7%) and seven (31.9%) patients. As well relief of pain as normalisation of cholestasis were significantly correlated with the irradiation doses applied. Median survival was 36.5 days for patients with lung cancer, 70.5 and 73 days for patients with breast and colorectal cancer. Irradiation doses given (10 to 18 Gy vs. 19 to 28 Gy vs. 29 to 48 Gy) and the status of disease (liver only vs. disseminated) were significantly correlated to prognosis (p = 0.00001, p = 0.0007). Patients of the high-dose group or patients with liver metastases alone revealed a median survival of 174 or 175 days. Since May 1991 simultaneous radio-chemotherapy, with the systemic application of leukovorine and 5-FU, was performed in eight patients with colorectal cancer. After performing a three-dimensional radiotherapy planning, which enclosed the whole liver inside the target volume, a mean dose of 29.4 Gy, with daily single fractions of 1.5 Gy was delivered. The follow-up, done with CT or NMR revealed in seven patients a progression free interval of three to 8.5 (5.5) months. After a median follow-up of 221 days the median survival was 333 days. In the treatment of patients with liver metastases a clear therapeutic selection has to be done according to valid prognostic criteria. In the majority of our patients with clinical symptoms, i.e. pain or cholestasis, irradiation alone was sufficient for palliation of these symptoms. Prognosis is limited because of the disseminated state of disease in 62% of the patients. In a group of patients, suffering from colorectal cancer with good prognostic criteria, the simultaneous application of radiotherapy and systemic chemotherapy was able to increase significantly the survival with minor toxicity.(ABSTRACT TRUNCATED AT 400 WORDS)