The results of this study demonstrate the value of interdisciplinary tumor board (ITB) discussions for patients with mCRPC. In this cohort, 42.9% of ITB recommendations adhered to established guidelines, while 57.1% deviated towards individualized treatment decisions. The fact that a substantial proportion of patients received non-standard recommendations highlights the importance of multidisciplinary input in ITB, which allows for patient-specific tailoring of treatment regimens. Interestingly, patients who received individualized treatment recommendations exhibited significantly longer OS, underscoring the clinical benefit of such approaches.

Several mechanisms may explain how ITB discussions improve patient outcomes. These include access to a broader range of expert opinions, a reduced risk of human error, and more coordinated care resulting from the involvement of multiple specialists (Huang et al. 2024). Furthermore, many novel or not yet fully approved therapies may be offered to patients via ITB consultations. A key example in our study is the early indication for PSMA-ligand therapy, which was recommended in 41.6% of patients, significantly prior to its official approval (Sartor et al. 2021; Keam 2022; Sar et al. 2023). During the study period, PSMA-ligand therapy had not yet received approval from the European Medicines Agency (EMA), which was granted only in December 2022 (Heilinger, et al. 2023). Consequently, even for patients who had already undergone chemotherapy with docetaxel and/or cabazitaxel, its use was considered off-label and required a tumor board decision for cost coverage. Noteworthy, the nowadays guideline-compliant decision to perform PSMA-PET/CT and PSMA-ligand therapy in our study was based on tumor board recommendations only and did not reflect NCCN® guidelines at the time. Similarly, olaparib, a PARP inhibitor, was not approved as a monotherapy for mCRPC following a positive Breast Cancer Gene 1 and Breast Cancer Gene 2 (BRCA1/2) mutation analysis, necessitating tumor board recommendations to facilitate cost coverage. In these cases, genomic testing to determine BRCA1/2 mutation status was specifically advised. This highlights the potential of ITB to facilitate access to cutting-edge therapies that might not be available outside of multidisciplinary settings.

In our analysis, 24.8% of patients were offered the option of participating in clinical trials. Clinical trial participation has been shown to improve outcomes for patients with mCRPC, and is strongly advocated by international consensus conferences, such as the Advanced Prostate Cancer Consensus Conference (APCCC) (Gillessen et al. 2023). In addition to clinical trial enrollment, ITB discussions provide access to modern targeted therapies, next-generation imaging, and advanced molecular analyses, especially in late-stage disease (Unger et al. 2016). While clinical guidelines are crucial in ITB decision-making, they are often challenged by the need to integrate novel, high-level evidence that may not yet be fully reflected in current recommendations (Winn et al. 1996).

Our study also identified key predictors of reduced OS in mCRPC, including renal impairment (GFR < 60 ml/min), symptomatic metastases, and visceral metastases. These findings are consistent with prior research demonstrating that visceral metastases, especially in sites such as the liver and lungs, are associated with poor prognosis in prostate cancer. Studies by Budnik et al. and Tappero et al. similarly reported that patients with visceral metastases had significantly worse survival outcomes compared to those with metastases confined to the bone (Budnik et al. 2019; Tappero 2023). Additionally, our findings align with other research suggesting that patients with multiple visceral metastases experience even poorer outcomes than those with isolated metastasis sites (Cui et al. 2020).

The role of symptomatic metastases as a marker of disease progression is well documented. Symptom onset or worsening in mCRPC is strongly associated with disease progression and shorter survival (Saad et al. 2018). The management of symptomatic metastases often requires individualized care, including interventions such as metastasis-directed radiotherapy (Boyer et al. 2014). In our investigation, 67.1% of patients had symptomatic metastases, and 14.9% received palliative radiotherapy.

Chronic renal impairment is highly prevalent in patients with mCRPC and is associated with increased cancer-related mortality (Launay-Vacher et al. 2016). The impact of renal function on drug pharmacokinetics and treatment toxicity must be carefully considered in treatment planning for this population (Launay-Vacher et al. 2016; Bednarek 2020). This is particularly relevant for agents such as novel hormonal therapies and chemotherapy, which can have detrimental effects on renal function (Bednarek 2020). The complex interplay between drug-drug interactions and renal impairment underscores the need for individualized dosing and therapeutic strategies, often achieved through ITB consultation (Papotti et al. 2021; Leeuwen et al. 2015).

Furthermore, molecular tumor boards (MTB) are gaining importance in mCRPC, particularly as more targeted therapies become available (Slootbeek et al. 2022). Recent studies have shown that genetically matched therapies recommended by MTB can lead to durable responses in a significant proportion of patients (Slootbeek et al. 2022). As biomarkers such as circulating tumor cells (CTC), DNA repair gene alterations, and androgen receptor splice variants become more widely implemented in clinical practice, ITB and MTB discussions will play a pivotal role in guiding personalized treatment for mCRPC (Slootbeek et al. 2022; Asif and Teply 2021).

Despite the strengths of this study, certain limitations must be acknowledged. First, all ITB recommendations were evaluated based on NCCN® guidelines, and any deviations were classified as individual therapies. However, some patients receiving individual therapies may have participated in clinical trials where guideline-compliant therapies were administered as part of control groups. Additionally, data on progression-free survival (PFS) were not available, limiting the ability to assess the impact of ITB recommendations on this important clinical endpoint. Our study is further limited by the fact that ITB registrations from external centers without patient admissions make it impossible to conduct an onsite assessment of the registered patients’ performance status based on the ECOG score in these cases.

Overall, in our study, individual treatment recommendations in ITB lead to improved OS in mCRPC. Therefore, urologists and oncologists treating CRPC patients in their daily practice should be encouraged to forward case discussions in an ITB. To date, utilization of ITB in genito-urinary cancer does not appear to be widespread everywhere (Heidenreich 2019; Atwell et al. 2019). Atwell et al. observed heterogeneous ITB referral rates depending on tumor entities at their institution (Atwell et al. 2019). While 90–100% of patients with lung cancer or upper gastrointestinal cancer were referred to ITB, only 34% and 28% of patients with prostate cancer and bladder cancer, respectively, were discussed in an ITB (Atwell et al. 2019).

It is important to note that establishing a formal ITB at regular intervals demands additional work time, as well as administrative and financial resources (Heidenreich 2019). Despite the substantial resource requirements, implementing ITB in specialized uro-oncology centers is beneficial, and both internal and external referrals should be encouraged, especially in the mCRPC scenario (Huang et al. 2024).