Management of small cell carcinoma of the bladder: Consensus guidelines from the Canadian Association of Genitourinary Medical Oncologists (CAGMO).

Small cell carcinomas (SCC) most commonly arise from the lung.1 These tumours are aggressive, present with early metastasis and are associated with a poorer prognosis compared to non-small cell lung cancer.2,3 Extra-pulmonary SCC was first described by Duguid and Kennedy in 19304 and subsequently has been reported in the gastrointestinal tract,5 head and neck6 and genitourinary (GU) system.7 SCC of the GU system (SCCGU) are uncommon, but can occur in the kidneys,8 renal pelvis,9 ureter,10 bladder,7 urachus,11 urethra12 and prostate.13 Although rare, these cancers are not insignificant. SCC accounts for 0.5% to 0.7% of all bladder cancers diagnosed.14,15 SCCGU also behaves more aggressively than typical GU histological counterparts.16 There is little medical literature to guide the optimal management of SCCGU malignancies and therefore treatment paradigms have by default mirrored those of the more common small cell carcinoma of the lung. Given the rarity of SCCGU tract and the lack of good clinical guidelines, it was clear that a guideline to help Canadian physicians and surgeons manage these patients with SCCGU was needed. This document achieves that goal for small cell carcinoma of the bladder (SCCB).