IS MICROSTAGING OF EARLY INVASIVE CANCER OF THE URINARY-BLADDER POSSIBLE OR USEFUL

Reports suggest that it is possible and useful to classify T1 (Stage A ) carcinomas of the urinary bladder into subgroups dependent on the de pth of invasion as defined by the muscularis mucosae (MM). In an attem pt to evaluate the reproducibility of these findings, we reviewed the slides from 77 cases of T1 bladder cancer diagnosed in 1983 in Iowa re sidents, The cases were identified through a statewide cancer registry , Slides and pathology reports were obtained from the original laborat ories. Two pathologists independently evaluated each case, most (74 ca ses) of which were transurethral resections, for the presence or absen ce of MM and three levels of invasion (lamina propria, MM, and submuco sa), Disagreements were resolved by simultaneous review resulting in a consensus diagnosis. Because of the population-based source, tissue h ad been obtained by multiple urologists and processed in multiple labo ratories, resulting in noticeable variation in quality of material, In terobserver agreement for level of invasion was poor between the two p athologists (kappa = 0.22; 95% C.I.=0.08-0.36). Consensus resulted in 34 cases (44.2%) invasive to the lamina propria, 23 (29.9%) to the MM, and 11 (14.3%) to the submucosa The level was indeterminate in nine ( 11.7%), All of the 77 cases were followed until death or 1993-95, with 57 patients dying during this interval, There were no significant dif ferences in survival for each level of invasion (lamina propria, MM, s ubmucosa) and the indeterminate cases, as determined by either consens us or individual observer evaluation, Our findings suggest that micros taging of early invasive bladder cancer is technically difficult and, at least in cases derived from various urologists and laboratories, do es not yield a prognostically significant separation.