Clinical outcome in metastatic prostate cancer after primary radiotherapy

PURPOSE: To describe a local radio-oncological treatment for patients with prostate cancer that metastasized to either the lymph nodes or distant regions. METHODS AND MATERIALS: We included 133 patients with prostate cancer that displayed either distant metastases (DM) or lymph node metastases alone (NM) and were treated between 2004 and 2019. All patients underwent computed tomography and a bone scan or 18F- or prostate-specific membrane antigen-targeted positron emission tomography. Patients received local external beam radiation therapy to the prostate to achieve local control (60–81.4 Gy to the prostate, and 45–50.4 Gy to pelvic lymph nodes), with either the 3D conformal (4-field box) or volumetric modulated arc therapy technique. A urologist prescribed additional therapy. RESULTS: We included 51 patients with DM and 82 patients with NM. The mean follow-up was 42 months for all patients. The groups were similar in T stage, initial prostate-specific antigen, histology, androgen deprivation therapy, age, treatment techniques, and prescribed doses, but different in lymph node inclusion and follow-up times. In the NM and DM groups, the 5‑year biochemical recurrence-free rates were 52% and 24%, respectively (p < 0.0001); the 5‑year disease-specific survival rates were 92% and 61%, respectively (p = 0.001); and the 5‑year OS rates were 77% and 48%, respectively (p = 0.01). The groups had similar acute and late gastrointestinal and genitourinary side effects, except that late genitourinary side effects occurred significantly more frequently in the NM group (p = 0.01). CONCLUSIONS: DM was associated with significantly worse outcomes than NM. The long-term survival of patients with metastatic prostate cancer was low.