This paper presents data on the risk of recurrence of osteosarcoma in the tissue exposed to radiation and freezed bone replants, used for replacing of bone defects in organ-preserving surgical operations on canine long bones. The best option of reconstructive surgery during replacement of bone graft in patients with bone tumors is obtaining of graft directly during the operation from the resected bone after pretreatment. One way of anticancer treatment of replanted bone is its single-phase exposition to radiation in vitro at the dose of 200 Gray (Gy) after preliminary freezing in liquid nitrogen vapor. Despite the ongoing treatment, there is a certain risk of recurrence of osteosarcoma in tissues of the replant