This study will enroll 60 women, older than 60 years of age, with breast cancer not more than 2 cm in size and without evident additional tumoral foci around the tumor or in other areas of the breast. An MSK radiologist will review your mammography to be sure you qualify for this study. You may be asked to undergo additional mammography or other examinations, such as breast ultrasound in order to verify that the tumor is located in a single quadrant of the breast. Some of these procedures are routinely performed in all candidates for conservative breast surgery.