Bone may be irradiated either as a target volume in the treatment of metastases or primary bone tumors, or as an organ at risk in soft tissue sarcomas (STS) and other cancers. This review aims to answer 5 key questions: 1. What are the causes, mechanisms, and locations of post-irradiation fractures (PIF)? Radiotherapy affects bone metabolism and surrounding soft tissues, contributing to fractures and complicating their treatment. In STS, periosteal stripping and radiation doses exceeding 50 Gy increase the risk of PIF, especially in the femur, which is the most frequently affected site. Fractures of the tibia, fibula, metatarsals, and upper limb are less common. PIF can also occur in the mandible (head and neck cancers), ribs or spine (lung and breast cancers), upper humerus, or pelvis. Osteoradionecrosis (ORN) is mostly associated with head and neck or maxillofacial sites but can affect other parts of the skeleton and pose significant therapeutic challenges. 2. How can post-irradiation fractures be prevented? Prevention of PIF mainly involves reducing skeletal radiation exposure and correcting any pre-existing osteopenia. Antioxidants and hyperbaric oxygen therapy are effective in preventing ORN. Preventive femoral nailing is recommended when general and especially local risk factors are present, such as during resection of STS of the thigh. Skeletal coverage with a flap can prevent complications caused by the sacrifice of soft tissue during resection of the primary tumor. 3. How is a post-irradiation fracture diagnosed? Some PIFs are easy to diagnose, while others are discovered fortuitously. It is important to differentiate PIFs from other lesions (metastasis, tumor progression, radiation-induced sarcoma, osteonecrosis), which may require a biopsy. 4. How are post-irradiation fractures treated? PIF treatment is associated with high rates of non-union and infection. Autologous bone grafts, and especially vascularized grafts, are recommended. Intra-medullary nailing is the preferred internal fixation technique. In certain cases, prosthetic replacement or even amputation may be necessary. 5. What are the specific features of radiotherapy in children and adolescents? Prevention and treatment of PIF in pediatric populations require a multidisciplinary approach, coordinated with the treatment of the underlying tumor, which remains the top priority.

Expert opinion.