Abstract
INTRODUCTION: Treatment for oligometastasis in prostate cancer has changed from systemic therapy to metastatic lesion-targeted therapy. Early detection of metastatic lesions and assessment of the treatment response have become very important. Therefore, we started to perfume assessments with whole-body magnetic resonance imaging, especially diffusion-weighted imaging with background body signal suppression, as a modality to detect metastasis in patients with prostate cancer. CASE PRESENTATION: We encountered two cases of castration-resistant prostate cancer in which oligometastasis was detected by diffusion-weighted imaging with background body signal suppression. Metastasis-directed therapy was initiated for to treat the lesions in each case. The treatment was effective for disease control and symptom relief. Diffusion-weighted imaging with background body signal suppression could detect new lesions at an early phase and delineate changes in lesions immediately after therapy. CONCLUSION: Diffusion-weighted imaging with background body signal suppression enables early decision-making for metastasis-directed therapy compared with conventional imaging modalities. Further, metastasis-directed therapy targeting oligometastatic lesions detected by diffusion-weighted imaging with background body signal suppression may improve patients' overall survival and quality of life.