Objectives: The incidence of renal cell carcinoma (RCC) has been rising, largely due to increased incidental detection from widespread imaging. Although synchronous distant metastasis (SM) with a primary renal tumor measuring <4 cm (cT1a) is uncommon, its presence may influence survival outcomes and the utility of cytoreductive nephrectomy. We sought to investigate clinical characteristics, metastatic patterns, treatments, and survival outcomes of patients with T1a RCC. Methods: All patients aged ≥18 years diagnosed with RCC between 2004 and 2019 were extracted from the National Cancer Database. The Cochran–Armitage test was used for trend analysis, while multivariable analyses were conducted to identify variables associated with SM and to assess the impact of cytoreductive surgery on mortality across isolated metastatic sites. Kaplan–Meier analysis was performed to compare survival outcomes. Results: A total of 263,911 individuals diagnosed with T1a RCC were analyzed in the study. Among them, 114,661 patients (43.4%) were classified as having cT1a tumor stage, and of these patients with cT1a RCC, 2275 (2.0%) exhibited SM. The proportion of SM cT1a was 3.39% in 2004 and 2.08% in 2019, with an Average Annual Percent Change (AAPC) of −0.037% (p = 0.830). The most common sites of metastasis were bone (59%), followed by lung (35%), liver (16%), and brain (12%). Resection of the primary tumor and receipt of systemic therapy were significantly associated with reduced mortality among all metastatic sites, especially in individuals with lung-only metastases (HR = 0.02, p = 0.013). Metastasectomy was associated with improved survival in patients with brain-only metastases (HR = 0.26, p = 0.006) but did not demonstrate the same benefit in patients with bone-, lung- or liver-only metastases. The worst 5-year OS rate was observed in cases with metastasis to multiple sites, whereas isolated metastases had similar survival rates (p < 0.0001). Our findings are limited by retrospective study design. Conclusions: This comprehensive analysis of T1a RCC patients reveals that while synchronous metastasis is relatively uncommon (2.0%), it presents significant clinical challenges, with bone as the most common metastatic site, contrasting with the typical lung predominance in larger tumors. Primary tumor resection showed survival benefit in patients with isolated metastases, especially for lung-only metastasis. These findings highlight the heterogeneous nature of tumor biology in small renal masses and underscore the importance of tailored, multimodal treatment strategies for the effective management of SM T1a RCC.

While multi-parametric magnetic resonance imaging (mpMRI) is known to be a specific and reliable modality for the diagnosis of non-metastatic prostate cancer (PC), positron emission tomography (PET) using ⁶⁸Ga labeled ligands targeting the prostate-specific membrane antigen (PSMA) is known for its reliable detection of prostate cancer, being the most sensitive modality for the assessment of the extra-prostatic extension of the disease and the establishment of a diagnosis, even before biopsy. Background/Objectives: Here, we compared these modalities in regards to the localization of intraprostatic cancer lesions prior to local HDR brachytherapy. Methods: A cohort of 27 patients received both mpMRI and PSMA-PET/CT. Based on 24 intraprostatic segments, two readers each scored the risk of tumor-like alteration in each imaging modality. The detectability was evaluated using receiver operating characteristic (ROC) analysis. The histopathological findings from biopsy were used as the gold standard in each segment. In addition, we applied a patient-based “congruence” concept to quantify the interobserver and intermodality agreement. Results: For the ROC analysis, we included 447 segments (19 patients), with their respective histological references. The two readers of the MRI reached an AUC of 0.770 and 0.781, respectively, with no significant difference (p = 0.75). The PET/CT readers reached an AUC of 0.684 and 0.608, respectively, with a significant difference (p < 0.001). The segment-wise intermodality comparison showed a significant superiority of MRI (AUC = 0.815) compared to PET/CT (AUC = 0.690) (p = 0.006). Via a patient-based analysis, a superiority of MRI in terms of relative agreement with the biopsy result was observed (n = 19 patients). We found congruence scores of 83% (MRI) and 76% (PET/CT, p = 0.034), respectively. Using an adjusted “near total agreement” score (adjacent segments with positive scores of 4 or 5 counted as congruent), we found an increase in the agreement, with a score of 96.5% for MRI and 92.7% for PET/CT, with significant difference (p = 0.024). Conclusions: This study suggests that in a small collective of low-/intermediate risk prostate cancer, mpMRI is superior for the detection of intraprostatic lesions as compared to PSMA-PET/CT. We also found a higher relative agreement between MRI and biopsy as compared to that for PET/CT. However, further studies including a larger number of patients and readers are necessary to draw solid conclusions.

Purpose The field of immunotherapy combinations for advanced renal cell carcinoma (aRCC) has been expanded in recent years. However, the treatment response varies widely among individual patients. It is still a challenge to predict oncological outcome in clinical practice. We assessed the impact of an activated immune system reflected by changes in C-reactive protein (CRP) levels and the early onset of treatment-related adverse events (TRAEs) on the treatment response. Methods In this retrospective analysis of 57 aRCC patients, CRP kinetics based on previous descriptions of CRP flare-response, CRP response or CRP non-response, and the TRAEs, which occurred within a month after therapy initiation, were obtained for this study. According to logistic regression analysis of both factors, we stratified the patients into risk groups: the presence of CRP flare-response/response and early onset of TRAE (low-risk group); the presence of a single factor (intermediate-risk group); and without both factors (high-risk group). Results Ten patients (17%) experienced primary disease progression. No progressive disease was observed in the low-risk group, while 60% (n = 6/10) of the high-risk group showed a primary disease progression. Significantly, an increased risk of disease progression was observed by patients without CRP response and TRAEs (p < 0.001). Conclusion The present analysis displays the predictive value of the on-treatment risk model based on CRP kinetics and the early onset of TRAEs, which can be easy to implement in clinical practice to optimize the treatment monitoring.

Micro-ultrasonography (microUS)-guided biopsy has emerged as an alternative to MRI fusion-guided biopsy for the diagnosis of prostate cancer. This study aimed to externally validate the PRI-MUS (Prostate Risk Identification using Micro-Ultrasound) scoring system for predicting clinically significant prostate cancer (csPCa) using data from the OPTIMUM trial. A secondary analysis of the OPTIMUM trial was conducted to evaluate the diagnostic performance of the PRI-MUS scoring system. The analysis included patients who underwent microUS-guided prostate biopsy, with each core assigned a PRI-MUS score. The diagnostic performance of the PRI-MUS scoring system for identifying csPCa was assessed at per-core and per-lesion levels. 347 patients receiving microUS-guided biopsy were included. At the per-core level, 4,590 biopsy cores were analyzed and assigned a PRI-MUS score. When comparing PRI-MUS 1-2 versus 3-5, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for detecting csPCa were 72%, 74%, 37%, and 93%, respectively. The AUC was 0.78 (95% [CI]: 0.76-0.8). At the per-lesion level, 322 lesions were analyzed. When comparing PRI-MUS 1-2 versus 3-5, the corresponding sensitivity, specificity, PPV, and NPV were 92%, 34%, 55%, and 83%, respectively. The AUC was 0.78 (95% CI: 0.73-0.82). Nineteen high-risk anterior lesions were biopsied, with csPCa detected in 11 (57.8%). The PRI-MUS scoring system demonstrated high sensitivity and NPV for diagnosing csPCa at both the per-core and per-lesion levels, supporting its validity as a risk-stratification tool for microUS-guided biopsy.