Recurrent oligometastatic transitional cell bladder carcinoma: is there room for radiotherapy?

This paper presents a retrospective report on radiotherapy (RT) in the oligometastastic recurrence of bladder cancer. Thirteen patients treated for low-volume metastatic transitional cell urinary bladder carcinoma (TCC) were reviewed, with the primary endpoint to evaluate the safety and efficacy of RT, proposed as an alternative to systemic treatment and/or to defer commencement of systemic therapy. The inclusion criteria were: patients who received RT without other local/systemic therapy for oligometastatic TCC with lymph node, bone and lung lesions or local recurrence. Previous systemic therapy and surgery on the primary tumor were allowed in this tumor response, and toxicity evaluation and progression free-survival was also assessed. Thirteen patients with 21 lesions were treated with stereotactic body radiotherapy (SBRT) or conformal 3D radiotherapy (3D-CRT) between 2012 and 2017. All participants were discussed by a multidisciplinary urological board. The median age at RT was 68 years (range 50-80), the median Karnofsky performance status (KPS) was 90 (range 80-90) and the median interval between TCC diagnosis and commencement of RT on oligometastasis was 23 months (range 8-105). The median treatment dose was 25 Gy (range 20-36 Gy) given over a median of 5 fractions (range 3-10 fractions) with a median follow-up of 25 months (range 3-43 months). Imaging assessment was available for 20 lesions. The radiological progression of disease was registered in 9 patients at the median of 4.2 months from radiotherapy (range 1.9-18.8 months). This identified in-field and out-field progression in 6 patients and only out-field progression in the remaining 3. At last contact, 3 patients were alive with no evidence of disease, 3 had evidence of disease, 6 died of cancer-related disease and one died from another cause. No severe acute and late toxicity was observed. The literature contains no consistent data on TCC oligometastatic setting, but radiotherapy on lymph node, bone and/or lung oligo-recurrence from TCC offers durable disease control in a small number of patients with a very low toxicity profile. Further studies are required to establish the radiotherapy role in oligometastatic recurrent bladder cancer.