Embodiments of the invention provide a system and method for resecting a tissue mass. The system for resecting a tissue mass includes a surgical instrument and a first sensor for measuring a signal corresponding to the position and orientation of the tissue mass. The first sensor is dimensioned to fit insider or next to the tissue mass. The system also includes a second sensor attached to the surgical instrument configured to measure the position and orientation of the surgical instrument. The second sensor is configured to receive the signal from the first sensor. A controller is in communication with the first sensor and/or the second sensor, and the controller executes a stored program to calculate a distance between the first sensor and the second sensor. Accordingly, visual, auditory, haptic or other feedback is provided to the clinician to guide the surgical instrument to the surgical margin.