Incidental diagnosis of bladder cancer in a national observational study in spain

Bladder cancer (BC) is a common malignancy in Spain. The aims of this study were: to identify the proportion of patients diagnosed with BC incidentally or after symptomatic presentation in a contemporary period in Spain; to compare demographic, clinical, and pathologic characteristics between these groups.

This was a retrospective analysis of a multi-centre observational study of 26 hospitals in the Spanish National Health System of all BCs newly diagnosed in 2011. The study represented 21.5% of the Spanish population and hospitals were selected in proportion to Spain's regions to ensure a representative sample. Patients were categorized by whether the cancer was diagnosed incidentally or after symptomatic presentation and baseline demographic, pathologic, and clinical characteristics were analyzed.

2472 were newly diagnosed with BC at the 26 participating Spanish hospitals with 308 (12.5%) of cases diagnosed incidentally and 2164 (87.5%) diagnosed after symptomatic presentation. No differences were observed between patients diagnosed incidentally vs. symptomatically in terms of demographics or measured co-morbidities. Compared to symptomatically diagnosed bladder tumours, those diagnosed incidentally were more likely to have a papillary appearance, to be significantly smaller, and less likely to have positive/suspicious cytology. Additionally, incidentally diagnosed bladder tumours were less likely to be muscle-invasive (11.7% vs. 25.0%, p < 0.01) nor aggressive at pathology, with 33.6% Grade 3 compared to 50.1%, (p < 0.01).

We identified a significant percentage (12.5%) of new bladder cancer diagnosis made incidentally in a representative sample of the Spanish population. These tumours exhibited less aggressive pathologic characteristics than their symptomatic counterparts.