Anti-cancer drug eluting stents prepared by supercritical fluid technology targeting urothelial tumors of upper urinary tract.

Upper tract urothelial carcinoma (UTUC) are fairly unusual compared to bladder cancer, but 60% of UTUCs are invasive at diagnosis. Urothelial carcinomas (UCs) are the fourth most common tumors [1]. They can be located in the lower (bladder and urethra) or upper (renal pelvis and ureter) urinary tract UTUCs account for 5-10% of UCs, with an estimated annual incidence in Western countries of ~2 cases per 100,000 inhabitants[1,2]. The conventional treatment is based on the use of anti-cancer drugs that have the ability to kill the cancer cells when in contact with them during some time. But the major problem in the conventional therapies is the short residence time and low penetration of the drug within the ureter, resulting in a need for frequent drug instillation. The ureter has a peristaltic movements and with the flow of the urine the contact time of the anti-cancer drugs with the cancer cells is not enough [3]. To avoid the problems of conventional therapies, such as the need for frequent instillation and poor tolerance we developed a biodegradable ureteral stent impregnated by supercritical fluid CO₂ (scCO₂) with the most commonly used anti-cancer drugs, namely epirubicin, doxorubicin, paclitaxel and gemcitabine. We hypothesized that the time of contact will be higher if the drugs flow from the stent placed in ureter instead need a frequent drug instillation and the deliver will be more local.