This document discusses the approach towards re-irradiation of common cancers. It begins by noting that local recurrence after radiation therapy and second primary tumors in irradiated areas are challenges, though re-irradiation can provide durable disease control in some cases. It then discusses key considerations for re-irradiation of head and neck cancers, gliomas, gynecological cancers, bone metastases, and brain metastases. Important factors include the initial radiation dose, interval since prior radiation, intent of re-irradiation, cumulative organ doses, and risk versus benefit. Advanced radiation techniques like IMRT can help minimize toxicity risks from re-irradiation. Careful patient selection and multidisciplinary evaluation are emphasized for meaningful survival benefits from re-