Serial circulating immune complex values and development of metastatic disease in breast cancer and malignant melanoma patients.

A polyethylene glycol precipitation technique was used to determine the levels of circulating immune complexes (CIC) in breast cancer and melanoma patients. All patients in the study had undergone surgery and were free of distant metastatic disease. CIC were measured at two to four time intervals, of 3 to 6 months each, over an average follow-up period of 13.5 months (range 7-20 months). In both groups of patients, metastatic disease developed with a higher frequency in patients who had undetectable CIC levels throughout the follow-up period or had become negative at the time metastases were discovered.