I have this theory that Tsunade might have not only mastered the art of Medical Jutsu in regards to healing, but also to reversing or stopping someones cellular regeneration. Medical Ninjutsu uses Yang release which governs vitality and physical life force. Yang Release is used to breath life into form. This is how she uses creation rebirth. But if she can do that, she must also be able to use it ina nreversed way to harm other people. As Kabuto said, when Orochimaru wanted her to heal his arms. She had a killing intent.