Factors predictive of completion of treatment and survival after palliative radiation therapy.

Ninety-seven patients who underwent radiation treatment for metastatic carcinomas and sarcomas were evaluated to define prognostic factors that may reliably help determine survival and probability of completing a course of palliative radiation therapy. Actuarial and logistic models were used for analysis. Predictor variables included age; sex; symptoms; primary site of disease; pathologic diagnosis; prior metastatic disease, treatment, and response; solitary versus multiple metastatic sites; location of metastasis; status of primary lesion; interval between initial diagnosis and treatment for metastatic disease; and Karnofsky performance score (KPS). The interval between primary diagnosis and metastatic treatment, and KPS, were significant variables for 22 patients (23%) who failed to complete their planned radiation treatment. KPS was consistently significant for probability of survival at 2-, 4-, 8-, and 16-month intervals. At 8 months and 16 months, site of primary disease was significant, and at 16 months, solitary site of metastasis was also significant. Conventional factors, especially KPS, are useful in predicting the likelihood of completing radiation therapy and of subsequent survival for patients undergoing palliative treatment.