The sensitivity of flow cytometry compared with conventional cytology in the detection of superficial bladder carcinoma.

Three groups of patients with superficial bladder carcinoma were studied: 110 patients had carcinoma in situ (TIS), 54 had noninvasive papillary transitional cell carcinoma (TA), and 64 had transitional cell carcinoma infiltrating the lamina propria (T1). One to six conventional cytologic examinations per patient (mean 2.8) were obtained during the 24 hour period before biopsy. For all tumor categories combined, the sensitivity was 49%, 54%, 62%, and 66% for one, two, three, and four cytologic examinations per patient, respectively. Cytologic sensitivity varied according to tumor category; it was greater in the TIS and T1 categories than in the TA category. To compare with the cytologic results, a subset of 103 patients had bladder irrigation performed immediately before the biopsy which was subsequently analyzed by flow cytometry. The sensitivity of a single flow cytometric examination for all tumor categories combined was 78%. As with the cytologic examinations, the sensitivity of flow cytometry varied with tumor category; it was greater in TIS and T1 categories than in the TA category. The sensitivity of one flow cytometric examination was superior (binomial test, P less than or equal to 0.05) to that of one or two cytologic examinations for TA tumors and to that of one, two, or three cytologic examinations for TIS, T1, and all tumor categories combined. Only three of 103 patients had their cancers detected by cytologic examination and not by flow cytometry.