Prostate treatment using fluid stream to resect prostate tissue, thereby relieving symptoms of conditions such as BPH, prostatitis, and prostatic carcinoma. A device having a fluid delivery element is positioned within a lumen of the urethra within the prostate. A fluid stream is directed outwardly from the fluid delivery element toward a wall of the urethral lumen. The fluid delivery element is moved to scan the fluid stream over the wall to remove a volume of tissue surrounding the lumen. The fluid may be combined with therapeutically active substances or with substances that increase resection efficiency. Fluid force may be adjusted to provide selective tissue resection such that soft tissue is removed while harder tissue is left undamaged. In order to gain a working space within the urethra, another fluid may be introduced to insufflate the urethra in the region of treatment.