Practical utility of specific red cell adherence test in bladder cancer.

There is a highly significant correlation between specific red cell adherence (SRCA) tests for ABO(H) blood group antigens and the biologic potential of a bladder cancer in terms of both superficial tumor recurrences and the subsequent development of invasive cancer. The correlation with superficial recurrences is of limited practical value because almost one half of patients with antigen-positive tumors have superficial recurrences. Similarly, because in approximately one third of patients with SRCA-negative tumors invasive cancer does not develop, SRCA tests cannot be used to select patients for early cystectomy. Because invasive cancer proceeds to develop in less than 10 per cent of patients with high-grade, antigen-positive tumors, SRCA tests may be of use to identify patients with high-grade tumors who deserve a trial of conservative therapy. SRCA tests must be interpreted with caution in patients who have been treated previously with radiation therapy or thiotepa, in whom false positive tests may occur, and in patients with type O blood in whom false negative tests may occur.