[Active Surveillance and Focal Therapy in Localized Prostate Cancer from the Perspective of Organ Preservation Strategy].

While the widespread use of PSA testing has led to early detection of prostate cancer, the increased diagnosis of clinically insignificant cancers has led to overtreatment, such as prostatectomy and radiation therapy. The side effects of this overtreatment may lead to a decline in the quality of life of patients. Therefore, organ- preservation strategies for localized prostate cancer are expected to combine cancer control with functional preservation and maintenance of quality of life. In this regard, active surveillance and focal therapy are ideal concepts in organ preservation. Active surveillance is an established strategy for low-risk and some intermediate-risk prostate cancers, and focal therapy is not yet recommended as primary therapy for localized prostate cancer in various guidelines. However, focal therapy as a primary treatment targets clinically significant cancer for intervention, while active surveillance is applied to manage other insignificant cancers, potentially highlighting a compatibility between the 2 approaches. We proposed a treatment strategy in which focal therapy is performed on localized lesions and then active surveillance is continued again when disease progression is observed during active surveillance. We believe that this approach is an effective way to avoid overtreatment and to maintain the patient's quality of life for a long time. Although uniformity in diagnostic imaging quality and establishment of treatment indication criteria are needed to realize this approach, it may become a new approach to prostate cancer treatment in the future.