Stereotactic radiosurgery for bone metastases in oligometastatic prostate cancer patients: DESTROY-2 clinical trial subanalysis.

INTRODUCTION: Aim of this analysis was to report toxicity and clinical outcomes in oligorecurrent prostate cancer (PCa) patients treated with single fraction stereotactic radiosurgery (SRS) for bone metastases. METHODS: We separately analyzed clinical data of PCa patients with bone oligometastases enrolled in a prospective phase I trial (DESTROY-2). DESTROY-2 was based on SRS delivered using volumetric modulated arc therapy in patients with primary or metastatic tumors in several extra-cranial body sites. Acute and late toxicity, biochemical tumor response, local control (LC), distant metastases-free (DPFS), progression-free (PFS), time to next-line systemic treatment-free (NEST-FS), and overall survival (OS) were calculated. RESULTS: Data on 37 PCa patients, carrying out 50 bone metastases, candidates for curative-intent treatment and treated with SRS at our Institution were collected. SRS dose ranged between 12 and 24 Gy. One grade 1 acute skin toxicity in one patient treated on the hip (24 Gy) and one grade 1 late skin toxicity in a patient with a scapular lesion (24 Gy) were recorded. No cases of bone fracture were registered in the treated population. With a median follow-up of 25 months (range 3-72 months) 2-year actuarial LC, DPFS, PFS, and OS were 96.7%, 58.1%, 58.1%, and 95.8%, respectively. Median and 2-year NEST-FS were 30 months (range 1-69 months) and 51.2%, respectively. CONCLUSIONS: Data analysis showed few toxicity events, high local control rate and prolonged NEST-FS after linear accelerator-based radiosurgery of bone oligometastases from PCa. The possibility of postponing systemic treatments in patients with oligometastatic PCa by means of SRS should be taken into account. Further prospective studies on larger series are needed to confirm the reported results.

Benefit of ablative versus palliative-only radiotherapy in combination with nivolumab in patients affected by metastatic kidney and lung cancer.

PURPOSE: Here, we present the results from a retrospective analysis, with the purpose of evaluating the safety and feasibility of nivolumab and radiotherapy (RT) concomitant association in metastatic kidney and lung cancer patients. MATERIALS AND METHODS: From August 2015 until September 2017, we retrospectively observed 20 patients with metastatic lung and renal cell carcinoma who had been initiated therapy with nivolumab and underwent concomitant RT. RT was administered either as an ablative therapy in the oligometastatic/oligoprogressive setting or as palliative-only treatment for symptomatic patients. Data on progression-free and overall survival (PFS and OS), treatment response and adverse events were collected and reported. Comparison between palliative-only and ablative treatments was performed. RESULTS: PFS and OS were 7 and 12.5 months in the entire population, respectively. Oligoprogressive patients treated with ablative intent, compared to patients undergoing RT with palliative-only intent, had statistically longer PFS (11.5 vs 5.2 months, HR 0.42, CI 0.18-0.98, p 0.03) and OS (17.9 vs 10.31 months, HR 0.41 CI 0.16-1.02, p 0.04). Considering only patients treated with ablative intent, 87.5% showed response to treatment, and complete response was reported in 37.5% of cases. Adverse G2-G3 related to combination treatment were reported as follows: 1 gastrointestinal (nausea), 4 breakthrough pain. CONCLUSIONS: Our data showed significant advantage for oligoprogressive patients treated with RT during nivolumab therapy. No safety alert emerged. These results underline the potential synergistic effects of RT and Immune therapy combination. Our analysis prompts further prospective studies exploring the benefit of integrated treatment strategies.