In recent years, minimally invasive treatments of solid tumors, such as image-guided radiofrequency (RF) ablation, have emerged as a powerful alternative therapy to surgery for patients with unresectable tumors. One major limitation of RF ablation is frequent recurrence of tumors due to incomplete destruction of cancerous cells at the tumor boundary. Biodegradable polymer millirods, composed of poly(D,L-lactide-co-glycolide) (PLGA) and impregnated with anti-cancer agents, have been designed to be implanted in tumors after RF ablation to deliver drugs to the surrounding tissue and kill the remaining tumor cells. By tailoring device design, it is possible to create dual-release polymer implants that incorporate both a burst release to rapidly raise the surrounding tissue drug concentrations as well as a sustained release to maintain those drug concentrations for an extended period of time. Combination of RF ablation with local drug therapy will provide a minimally invasive paradigm for the effective treatment of solid tumors.