Radiotherapy for Oligometastatic Prostate Cancer

The knowledge that disease progression after chemotherapy often occurs in areas affected by the disease at the time of diagnosis has given rise to the concept of oligometastasis. Although it is difficult to define oligometastatic disease clearly, most studies include cases with up to 3-5 metastases in this group. This review aimed to elucidate the role of radiotherapy in oligometastatic prostate cancer, identify appropriate radiotherapy modalities, and establish appropriate dose/fraction schemes. We can discuss radiotherapy for oligometastatic prostate cancer under two main headings: metastasis-directed therapy (MDT) and primary treatment. Most studies on MDT in patients with oligometastatic prostate cancer are retrospective; however, in the results, it is noteworthy that a group of patients benefit from MDT within the classification defined as "oligometastasis". Studies on primary-directed radiotherapy for oligometastatic prostate cancer have revealed the potential benefits of curative treatment. These results should be supported by prospective phase 3 studies. We observed that stereotactic body radiotherapy (SBRT) is a frequently used radiotherapy technique for oligometastatic prostate cancer. The capability of the treatment machine, the location and size of the metastasis, and patient immobilization should be taken into consideration for dose/fraction selection. MDT and primary-directed treatment can slow disease progression in patients with oligometastatic prostate cancer. SBRT is the most commonly preferred treatment modality for this purpose. Prospective studies are needed to clearly define the patient group that will benefit from treatment.