BACKGROUND: The sacroiliac (SI) joint is a common cause of low back pain, for which radiofrequency (RF) denervation has been shown to provide long-term relief. However, controversy exists surrounding the innervation, which treatment paradigm to utilize, and how best to select patients who might benefit. OBJECTIVE: To describe a patient with terminal breast cancer and tumor infiltration of the sacroiliac joint who was treated with cooled RF of the sacral lateral branches as an end-of-life palliative measure. The objectives of this review are to provide insight into the innervation of the SI joint; address controversial issues surrounding the targeted nerves in a patient with transitional anatomy; outline risk-mitigation strategies; and highlight the need for individually tailored treatment plans. METHODS: Case-based focused literature review in a patient treated with cooled RF ablation of the L4-S3 primary dorsal rami and lateral branches. RESULTS: Treatment was tailored to facilitate the rapid treatment of this terminal patient by performing the prognostic blocks and RF ablation at the same visit. Until her death 5 days post-procedure, the patient reported significant pain relief and began to ambulate and use the bathroom on her own, activities she could not do before treatment. In addition to functional improvement, she was also able to significantly reduce her opioid intake. CONCLUSION: This is the first report of cooled SI joint RF ablation to treat cancer pain. Our patient's positive response to the procedure suggests the possibility that the lateral branches innervate not only the posterior ligaments, but also the bony articulation. The decision to proceed with RF ablation on the same day as a prognostic lateral branch block was based on our patient's terminal condition, and the fact that cooled RF does not require sensory stimulation to ensure proximity to the target nerves. Because of her transitional anatomy, we elected to target L4.