Four hundred patients who were radically treated for breast carcinoma during the period May 1974 to December 1980 were followed for a minimum of 4 years. The outcomes of the 128 patients with recurrences were studied. A differentiation into two groups was made: those in whom recurrences were detected as a real result of follow-up (27%) and those in whom this was not the case (73%). Both groups were comparable as regards age, period "at risk," nature and site of recurrence, type of therapy instituted, and their response to it. No differences could be found in any of these factors. The recurrence-free interval, the survival after institution of therapy, and the total survival after the primary procedure were the same in both groups.