Pattern of recurrence after stereotactic body radiotherapy for para-aortic oligo-recurrent prostate cancer, a multicentric analysis.

BACKGROUND: M1a disease represents an intermediate status between loco-regional relapse and bone metastatic disease. Metastasis directed therapy (MDT), through stereotactic body RT (SBRT) may be offered to patients, aiming to exclusively treat sites of macroscopic relapse and avoiding wide prophylactic treatment volumes. This appears as a viable treatment, especially after the rise of PSMA tailored treatment approaches. MATERIALS AND METHODS: Data about patients treated in two different institutions were retrieved from a prospectively collected dataset. All included patients were affected by oligo-recurrent M1a disease after definitive RT or radical prostatectomy, defined as ≤ 3 nodal lesions situated above aortic bifurcation and below renal arteries. Both castration resistant PCa (CRPC) and castration sensitive (CSPC) PCa patients were included. All imaging methods were allowed to detect recurrence (CT scan, Choline or PSMA PET/CT).All sites of recurrences were treated with SBRT. RESULTS: Median PFS was 10 months (95% CI 8-17). Twelve patients died, with a median OS of 114 months (95% CI 85-114). Out of the 83 recurrences, 2 (2.4%), 11 (13.25%), 36 (43.37%) and 15 (18%) patients had respectively prostate bed only, pelvic nodal, para-aortic or distant relapse. Furthermore, 19 (22.9%) patients experienced a biochemical only relapse with negative imaging at re-staging. DISCUSSION: MDT conferred a remarkable PFS outcome in a mixed cohort of CSPC and CRPC patients with m1a disease, with an optimal safety profile. Prospective trials are needed in order to compare MDT and ENRT for these patients, allowing to select the best treatment option.

Three Months' PSA and Toxicity from a Prospective Trial Investigating STereotactic sAlvage Radiotherapy for Macroscopic Prostate Bed Recurrence after Prostatectomy-STARR (NCT05455736).

Biochemical recurrences after radical prostatectomy (RP) can be managed with curative purpose through salvage radiation therapy (SRT). RT dose escalation, such as stereotactic RT (SSRT), may improve relapse-free survival in this setting. STARR trial (NCT05455736) is a prospective multicenter study including patients affected by macroscopic recurrence within the prostate bed after RP treated with SSRT. Recurrence was detected with a Choline or PSMA CT-PET. In the current analysis, the early biochemical response (BR) rate and toxicity profile after three months of follow-up were assessed. Twenty-five patients were enrolled, and data about BR and toxicity at three months after treatment were available for 19 cases. Overall, BR was detected after three months in 58% of cases. Four G1-G2 adverse events were recorded; no G ≥ 3 adverse events were detected. SSRT appears feasible and safe, with more than half of patients experiencing BR and an encouraging toxicity profile. The STARR trial is one of the few prospective studies aimed at implementing this promising treatment strategy in this scenario.

Predictive factors for tolerance to taxane based chemotherapy in older adults affected by metastatic prostate cancer (ANCHISES-NCT05471427): A prospective observational trial including patients with metastatic hormone sensitive and castrate resistant prostate cancer treated with taxane chemotherapy.

INTRODUCTION: Taxane-based chemotherapy is one of the main cornerstones for treatment of metastatic prostate cancer (mPCa). In aged and well-fit patients, an indication for taxane chemotherapy should remain similar to the general population. Aiming to explore predictive factors of fitness to taxane chemotherapy in older adult patients, a prospective observational study was carried out in our institution. MATERIALS AND METHODS: We collected data from a prospective mono-centric database of patients aged ≥70 years old that were treated in our department. All patients underwent taxane treatment (either docetaxel or cabazitaxel, the latter only in second line setting) starting with standard treatment schedules (75 mg/m2 or 25 mg/m2 every three weeks, respectively). Data about G8 score post treatment decreases were collected and reported. We explored associations between baseline age, G8 score, and Charlson Comorbidity Index (CCI) with taxane dose reduction (DR), treatment temporary suspension (TS), or definitive interruption (TDI). Logistic regression analysis was performed to explore potential predictive factors for tolerability in patients treated with docetaxel. RESULTS: One hundred-eighteen patients underwent taxane chemotherapy between 2011 and 2022, the majority of cases in metastatic castrate resistant prostate cancer (mCRPC) setting (85.6%). In the overall population, DR was performed in 40.7% of cases, and TS and TDI were deemed necessary in 28% and 22.9% of patients, respectively. Forty-seven percent of patients reported a significant deterioration in terms of G8 score (from > to ≤14). Sixty-two percent of the overall population were deemed fit for further treatment after taxane chemotherapy. Rate of DR, TS, and TDI was 29.4%, 11.8% and 9.2% in the docetaxel subgroup, vs 48%, 60% and 12% of patients treated with cabazitaxel, respectively. Lower baseline G8 was reported as a continuous variable and the only independent predictive factor for TDI in docetaxel subgroup (odds ratio [OR] 0.41, 95% confidence interval [CI] 0.25-0.68, p = 0.0008). DISCUSSION: Our data suggest that tolerability of taxane regimens in a pre-treated population of older patients with prostate cancer is acceptable, despite a non-negligible rate of TDI. Taxane chemotherapy should not be denied a priori in order to avoid undertreatment of older adult patients.

Prospective assessment of AR splice variant and multi-biomarker expression on circulating tumor cells of mCRPC patients undergoing androgen receptor targeted agents: interim analysis of PRIMERA trial (NCT04188275).

Circulating tumor cells detection and ARV7 expression are associated with worse clinical outcomes in metastatic Castration-Resistant Prostate Cancer (mCRPC) undergoing Androgen Receptor Targeted Agents. ARFL, PSMA and PSA may help to refine prognostic models. In our institution, a prospective observational trial testing CTC detection in mCPRC undergoing I line ARTA therapy terminated the planned enrollment in 2020. Here, we present a pre-planned interim analysis with 18 months of median follow-up. RT-qPCR was used to determine the CTC expression of PSA, PSMA, AR and ARV7 before starting ARTA. PSA-drop, Progression-Free and Overall Survival (PFS and OS) and their correlation with CTC detection were reported. Forty-four patients were included. CTC were detected in 43.2% of patients, of whom 8.94% expressed PSA, 15.78% showed ARV7, 63.15% and 73.68% displayed ARFL and PSMA, respectively. Biochemical response was significantly improved in CTC + vs CTC- patients, with median PSA-drop of 18.5 vs 2.5 ng/ml (p = 0.03). After a median follow-up of 18 months, 50% of patients progressed. PFS was significantly longer in CTC- patients (NR vs 16 months). Eight (18.2%) patients died, a non-significant trend in terms of OS was detected in favor of CTC- patients (NR vs 29 months, p = 0.05). AR, PSA and PSMA expression in CTC + had no significant impact on PSA-drop, PFS or OS. PRIMERA-trial confirmed the CTC detection predictive importance in mCRPC patients.