Optimal management of recurrent and metastatic upper tract urothelial carcinoma: Implications of intensity modulated radiation therapy.

<bold>Background: </bold>Upper tract urothelial carcinoma (UTUC) is rare and the treatment for recurrent or metastatic UTUC is unclear. We evaluated the outcomes of salvage and palliative radiotherapy (RT) and prognostic factors in UTUC patients and find implications for salvage and palliative RT.<bold>Methods: </bold>Between August 2006 and February 2021, 174 patients (median age, 68 years; range, 37-90) underwent salvage and palliative RT. Disease status at RT included initially diagnosed advanced disease (n = 8, 4.6%), local recurrence only (n = 56, 32.2%), distant metastasis only (n = 59, 33.9%), and local recurrence and distant metastasis (n = 51, 29.3%). The primary tumor location included the renal pelvis (n = 87, 50%), ureter (n = 77, 44.3%), and both (n = 10, 5.7%). Radical nephroureterectomy, chemotherapy, and immunotherapy were used in 135 (77.6%), 101 (58%), and 19 (10.9%) patients, respectively. Survival outcomes and prognostic factors were analysed using Cox and logistic regression analysis.<bold>Results: </bold>Salvage RT and palliative RT was administered in 73 (42%) and 101 (58%) patients, respectively. The median radiation dose was 45 Gy (range, 15-65). Two-dimensional (2D) or three-dimensional (3D) RT and intensity modulated RT (IMRT) were used in 61 (35.1%) and 113 (64.9%) patients, respectively. The median follow-up was 7.8 months. The median duration of overall survival (OS) was 13.4 months, and the 1-year OS was 53.5%. The median progression-free survival (PFS) was 4.7 months, and the 6-month PFS was 41.9%. The 6-month infield PFS was 84%. In multivariate analysis, RT method (2D/3D vs. IMRT, p = 0.007) and RT response (p = 0.008) were independent prognostic factors for OS, and RT response correlated with PFS (p = 0.015). In subgroup analysis in patients with PD-L1 data, positive PD-L1 correlated with better PFS (p = 0.009). RT response-associated factors were concurrent chemotherapy (p = 0.03) and higher radiation dose (p = 0.034). Of 145 patients, 10 (6.9%) developed grade 3 acute or late toxicity.<bold>Conclusions: </bold>Salvage and palliative RT for UTUC are feasible and effective. Patients with RT response using IMRT may have survival benefit from salvage and palliative RT. Positive PD-L1 status might be related to radiosensitivity. High-dose radiation with concurrent chemotherapy may improve RT response. [ABSTRACT FROM AUTHOR]