New EAU/ASCO guideline recommendations on sentinel node biopsy for penile cancer and remaining challenges from a nuclear medicine perspective.

INTRODUCTION: The European Association of Urology (EAU) and the American Society of Clinical Oncology (ASCO) recently issued updated guidelines on penile cancer, emphasising dynamic sentinel node biopsy (DSNB) as the preferred method for surgical staging among patients with invasive penile tumours and no palpable inguinal lymphadenopathy. This paper outlines the rationale behind this new recommendation and describes remaining challenges, as well as strategies for promoting DSNB worldwide. MAIN TEXT: DSNB offers high diagnostic accuracy with the lowest postoperative complications compared to open or minimally invasive inguinal lymph node dissection (ILND), prompting its preference in the new guidelines. Nevertheless, despite its advantages, there are challenges hampering the widespread adoption of DSNB. This includes the false-negative rate associated with DSNB and the potential negative impact on patient outcome. To address this issue, improvements should be made in several areas, including refining the timing and interpretation of the lymphoscintigraphy and the single photon emission computed tomography/computed tomography images. In addition, the quantity of tracer employed and choice of the injection site for the radiopharmaceutical should be optimised. Finally, limiting the removal of nodes without tracer activity during surgery may help minimise complication rates. CONCLUSION: Over the years, DSNB has evolved significantly, related to the dedicated efforts and innovations in nuclear medicine and subsequent clinical studies validating its efficacy. It is now strongly recommended for surgical staging among selected penile cancer patients. To optimise DSNB further, multidisciplinary collaborative research is required to improve SN identification for better diagnostic accuracy and fewer complications.

Penile cancer care in the Netherlands: increased incidence, centralisation, and improved survival.

OBJECTIVE: To evaluate penile squamous cell carcinoma (PSCC) incidence and centralisation trends in the Netherlands over the past three decades, as well as the effect of centralisation of PSCC care on survival. PATIENTS AND METHODS: In the Netherlands PSCC care is largely centralised in one national centre of expertise (Netherlands Cancer Institute [NCI], Amsterdam). For this study, the Netherlands Cancer Registry, an independent nationwide cancer registry, provided per-patient data on age, clinical and pathological tumour staging, follow-up, and vital status. Patients with treatment at the NCI were identified and compared to patients who were treated at all other centres. The age-standardised incidence rate was calculated with the European Standard Population. The probability of death due to PSCC was estimated using the relative survival. Multivariable Cox regression analysis was performed to evaluate predictors of survival. RESULTS: A total of 3160 patients were diagnosed with PSCC between 1990 and 2020, showing a rising incidence (P < 0.001). Annual caseload increased at the NCI (1% in 1990, 65% in 2020) and decreased at other (regional) centres (99% to 35%). Despite a relatively high percentage of patients with T2-4 (64%) and N+ (33%) at the NCI, the 5-year relative survival was higher (86%, 95% confidence interval [CI] 82-91%) compared to regional centres (76%, 95% CI 73-80%, P < 0.001). Patients with a pathological T2 tumour were treated with glans-sparing treatment more often at the reference centre than at the regional centres (16% vs 5.0%, P < 0.001). After adjusting for age, histological grading, T-stage, presence of lymph node involvement and year of diagnosis, treatment at regional centres remained a predictor for worse survival (hazard ratio 1.22, 95% CI 1.05-1.39; P = 0.006). CONCLUSION: The incidence of PSCC in the Netherlands has been gradually increasing over the past three decades, with a noticeable trend towards centralisation of PSCC care and improved relative survival rate.

Comparison of two hybrid sentinel node tracers: indocyanine green (ICG)-99mTc-nanocolloid vs. ICG-99mTc-nanoscan from a nuclear medicine and surgical perspective.

BACKGROUND: Lymph node (LN) metastasis is a relevant predictor for survival in patients with a.o. penile cancer (PeCa), malignant melanoma. The sentinel node (SN) procedure comprises targeted resection of the first tumour-draining SNs. Here, the hybrid tracer indocyanine green (ICG)-99mTc-nanocolloid has been used for several years to combine optical and nuclear detection. Recently, the resource of the nanocolloid precursor stopped production and the precursor was replaced by a different but chemically comparable colloid, nanoscan. Our aim was to study the performance of ICG-99mTc-nanoscan compared to ICG-99mTc-nanocolloid from a nuclear and surgical perspective. METHODS: Twenty-four patients with either PeCa or head-and-neck (H&N) melanoma and scheduled for a SN procedure were included. The initial group (n = 11) received ICG-99mTc-nanocolloid until no longer available; the second group (n = 13) received ICG-99mTc-nanoscan. Tracer uptake was assessed on lymphoscintigraphy and single-photon emission (SPECT). Intraoperatively, SNs were identified using gamma tracing and fluorescence imaging. Ex vivo (back-table) measurements were conducted to quantify the fluorescence emissions. Chemical analysis was performed to compare the ICG assembly on both precursors. RESULTS: The mean tracer uptake in the SNs was similar for ICG-99mTc-nanocolloid (2.2 ± 4.3%ID) and ICG-99mTc-nanoscan (1.8 ± 2.6%ID; p = 0.68). 3 SNs (interquartile range (IQR) 3-4) were detected on lymphoscintigraphy in PeCa patients receiving ICG-99mTc-nanoscan compared to 2 SNs (IQR 2-3) in PeCa patients receiving ICG-99mTc-nanocolloid (p = 0.045), no differences were observed in H&N patients. Back-table measurements of resected SNs revealed a lower total fluorescence intensity in the ICG-99mTc-nanoscan group (24*109 arbitrary units (A.U) IQR 1.6*109-14*109 in the ICG-99mTc-nanocolloid group versus 4.6*109 A.U. IQR 2.4*109-42*109 in the ICG-99mTc-nanoscan group, p = 0.0054). This was consistent with a larger degree of "stacked" ICG observed in the nanoscan formulation. No tracer-related adverse events were reported. CONCLUSIONS: Based on this retrospective analysis, we can conclude that ICG-99mTc-nanoscan has similar capacity for SN identification as ICG-99mTc-nanocolloid and can safely be implemented in SN procedures.

Single-cell Atlas of Penile Cancer Reveals TP53 Mutations as a Driver of an Aggressive Phenotype, Irrespective of Human Papillomavirus Status, and Provides Clues for Treatment Personalization.

BACKGROUND AND OBJECTIVE: TP53 loss-of-function (TP53LOF) mutations might be a driver of poor prognosis and chemoresistance in both human papillomavirus (HPV)-independent (HPV-) and HPV-associated (HPV+) penile squamous cell carcinoma (PSCC). Here, we aim to describe transcriptomic differences in the PSCC microenvironment stratified by TP53LOF and HPV status. METHODS: We used single-cell RNA sequencing (scRNA-seq) and T-cell receptor sequencing to obtain a comprehensive atlas of the cellular architecture of PSCC. TP53LOF and HPV status were determined by targeted next-generation sequencing and sequencing HPV-DNA reads. Six HPV+ TP53 wild type (WT), six HPV- TP53WT, and four TP53LOF PSCC samples and six controls were included. Immunohistochemistry and hematoxylin-eosin confirmed the morphological context of the observed signatures. Prognostic differences between patient groups were validated in 541 PSCC patients using Kaplan-Meier survival estimates. KEY FINDINGS AND LIMITATIONS: Patients with aberrant p53 staining fare much worse than patients with either HPV- or HPV+ tumors and WT p53 expression. Using scRNA-seq, we revealed 65 cell subtypes within 83 682 cells. TP53LOF tumors exhibit a partial epithelial-to-mesenchymal transition, immune-excluded, angiogenic, and morphologically invasive environment, underlying their aggressive phenotype. HPV- TP53WT tumors show stemness and immune exhaustion. HPV+ TP53WT tumors mirror normal epithelial maturation with upregulation of antibody-drug-conjugate targets and activation of innate immunity. Inherent to the scRNA-seq analysis, low sample size is a limitation and validation of signatures in large PSCC cohorts is needed. CONCLUSIONS AND CLINICAL IMPLICATIONS: This first scRNA-seq atlas offers unprecedented in-depth insights into PSCC biology underlying prognostic differences based on TP53 and HPV status. Our findings provide clues for testing novel biomarker-driven therapies in PSCC. PATIENT SUMMARY: Here, we analyzed tissues of penile cancer at the level of individual cells, which helps us understand why patients who harbor a deactivating mutation in the TP53 gene do much worse than patients lacking such a mutation. Such an analysis may help us tailor future therapies based on TP53 gene mutations and human papillomavirus status of these tumors.

Corporal Skip Metastases in Penile Squamous Cell Carcinoma: An Unknown and Distinct Pattern of Spread with Poor Prognosis.

BACKGROUND: Penile squamous cell carcinoma (PSCC) is characterised by stepwise lymphatic dissemination. Skip metastases (SkMs) are rare metastases in the corpus cavernosum or spongiosum without continuity to the primary tumour or its resection site. OBJECTIVE: To assess the distinct pattern of spread in SkM+ patients and the effect of SkM on prognosis. DESIGN, SETTING, AND PARTICIPANTS: We conducted a retrospective analysis of patients with SkM+ PSCC at ten high-volume international referral centres between January 2006 and May 2022. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We evaluated histopathological data, primary lymph node (LN) staging, and metastatic spread. We included a cohort of patients matched for pT stage, LN status, and grade who did not have SkM (SkM-) to compare the SkM prognosis and predictive value for cancer-specific mortality (CSM). RESULTS AND LIMITATIONS: Among the 63 SkM+ patients who met our inclusion criteria, the SkM diagnosis was synchronous in 54.0% and metastases were mostly located in the corpus cavernosum. SkM was symptomatic in 14% of cases, was detected on imaging in 32%, and was found incidentally on pathological examination in 27%. Fifty-one patients (81%) presented with positive LNs and 28 (44%) developed distant metastases. Seven patients (11%) presented with or developed distant metastasis without displaying any LN involvement. The 2-yr cancer-specific survival estimates were 36% (95% confidence interval [CI] 25-52%) for SkM+ and 66% (95% CI 55-80%) for matched SkM- patients (p < 0.001). On multivariable Cox regression analysis, SkM presence was an independent predictor for higher CSM (hazard ratio 2.05, 95% CI 1.06-4,12; p = 0.03). CONCLUSIONS: PSCC-related SkM is associated with aggressive disease behaviour and poor survival outcomes. Palpation of the entire penile shaft is essential, and distant staging is recommended in patients suspected of having SkM owing to the tendency for distant metastatic spread. PATIENT SUMMARY: We investigated outcomes for patients with cancer of the penis who had metastases in the tissues responsible for erection. We found that metastases in this location were associated with poor prognosis, even in the absence of more typical spread of cancer via the lymph nodes.