The disclosure describes a method and a system that may be used to provide feedback on the progress of ablation therapy. The system includes a first needle that penetrates a target tissue to deliver radio frequency energy, with or without a conductive fluid, that heats and ablates the target tissue and a second needle that penetrates the target tissue and detects a tissue property indicative of the ablation progress. Temperature, impedance, or another parameter may be the tissue property detected and measured by the system. In addition, more than one sensor may be positioned on the first or second needle. The system may provide real-time monitoring of the tissue property or use the tissue property measurement to automatically terminate the ablation therapy. In particular, the system may be used to treat benign prostatic hypertrophy.