A method and apparatus for direct interstitial treatment of tissue, while preventing backflow and decreasing drainage of a flowable composition from an injected area, by using a catheter and / or a needle with single or multiple inflatable member(s) that stretches, dilates and compresses target tissue and allows for an improved interstitial deposition, distribution and retention of the flowable composition, drug(s), agent(s), or particle(s), into a body organ, fluid, tissue, or tumor, thereby increasing procedural safety and efficacy of direct interstitial therapies.