Management of the Clinically Negative (cN0) Groin Penile Cancer Patient: A Review

[The malignant epithelial carcinomas of the penis: A review of the different histological types]

The most frequent cancer of the penis is the squamous cell carcinoma. Several variants of squamous cell carcinoma exist. It is important to make a difference between squamous cell carcinomas with and without a HPV infection. Furthermore, it is extremely important to recognize the different variants as their prognosis differs. These tumors are rare therefore classifying them can be challenging. This review is supposed to give an overview on the existing entities since 2016, but also allows a glimpse into the future with some comments on the upcoming WHO classification 2021.

The role of fluorescent and hybrid tracers in radioguided surgery in urogenital malignancies

The increasing availability of new imaging technologies and tracers has enhanced the application of nuclear molecular imaging in urogenital interventions. In this context, preoperative nuclear imaging and radioactivity-based intraoperative surgical guidance have become important tools for the identification and anatomical allocation of tumor lesions and/or suspected lymph nodes. Fluorescence guidance can provide visual identification of the preoperatively defined lesions during surgery. However, the added value of fluorescence guidance is still mostly unknown. This review provides an overview of the role of fluorescence imaging in radioguided surgery in urogenital malignancies. The sentinel node (SN) biopsy procedure using hybrid tracers (radioactive and fluorescent component) serves as a prominent example for in-depth evaluation of the complementary value of radio- and fluorescence guidance. The first large patient cohort and long-term follow-up studies show: 1) improvement in the SN identification rate compared to blue dye; 2) improved detection of cancer-positive SNs; and 3) hints towards a positive effect on (biochemical) recurrence rates compared to extended lymph node dissection. The hybrid tracer approach also highlights the necessity of a preoperative roadmap in preventing incomplete resection. Recent developments focus on receptor-targeted approaches that allow intraoperative identification of tumor tissue. Here radioguidance is still leading, but fluorescent and hybrid tracers are also finding their way into the clinic. Emerging multiwavelength approaches that allow concomitant visualization of different anatomical features within the surgical field may provide the next step towards even more refined procedures.

Contemporary Incidence and Predictors of Occult Inguinal Lymph Node Metastases in Men With Clinically Node-negative (cN0) Penile Cancer

OBJECTIVE

To (1) examine the contemporary incidence of occult inguinal LN metastases and (2) identify predictors of occult inguinal LN metastases to improve selection of cN0 patients for inguinal lymphadenectomy (ILND).

METHODS

We identified 590 men with cTany cN0 cM0 penile cancer who underwent partial/radical penectomy and ILND from 2006-2016 in the NCDB. Rates of pN+ disease were examined, and a multivariable regression model was constructed to identify features associated with pN+ disease.

RESULTS

Tumors were ≤pT1 in 21%, pT2 in 43%, and pT3/pT4 in 24% of patients. A median of 15 (IQR 8-22) LNs were removed at ILND. The overall pN+ rate was 24% and did not vary over the study period. The pN+ rate, stratified by pT stage, varied from 18-33%. On multivariable analysis, only higher tumor grade (OR 2.16; P = 0.02 for grade 2; OR 2.81; P = 0.005 for grade 3-4, versus grade 1) and lymphovascular invasion (OR 3.12; P <0.001) were independently associated with pN+ disease, whereas pT stage was not.

CONCLUSION

The contemporary rate of occult LN metastases in men with cN0 penile cancer remains high at approximately 24%. Our results suggest that high tumor grade and/or lymphovascular invasion are better determinants of lymph node involvement than primary tumor stage.

Interventional nuclear medicine: a focus on radioguided intervention and surgery

Within interventional nuclear medicine (iNM) a prominent role is allocated for the sub-discipline of radioguided surgery. Unique for this discipline is the fact that an increasing number of clinical indications (e.g. lymphatic mapping, local tumor demarcation and/or tumor receptor targeted applications) have been adopted into routine care. The clinical integration is further strengthened by technical innovations in chemistry and engineering that enhance the translational potential of radioguided procedures in iNM. Together, these features not only ensure ongoing expansion of iNM but also warrant a lasting clinical impact for the sub-discipline of radioguided surgery.

Recent advances in the synthesis of (99mTechnetium) based radio-pharmaceuticals

Technetium radionuclide (99mTc) has excellent extent of disintegration properties and occupies a special place in the field of nuclear medicinal chemistry and other health disciplines. Current review describes recent approaches of synthesis in detailed ways for radio-pharmaceuticals of technetium which have been developed to treat and diagnose the biotic disorders. These technetium labeled radio-pharmaceuticals have been established to apply in the field of diagnostic nuclear medicine especially for imaging of different body parts such as brain, heart, kidney, bones and so on, through single photon emission computed tomography (SPECT) that is thought to be difficult to image such organs by using common X-ray and MRI (Magnetic Resonance Imaging) techniques. This review highlights and accounts an inclusive study on the various synthetic routes of technetium labeled radio-pharmaceuticals using ligands with various donor atoms such as carbon, nitrogen, sulphur, phosphorus etc. These compounds can be utilized as next generation radio-pharmaceuticals.

Potential Receptors for Targeted Imaging of Lymph Node Metastases in Penile Cancer

Imaging modalities using tumor-directed monoclonal antibodies may be of value to improve the pre- and intraoperative detection and resection of lymph node (LN) metastatic disease in penile squamous cell carcinoma (PSCC). We investigated the expression of prostate-specific membrane antigen (PSMA), vascular endothelial growth factor (VEGF), epidermal growth factor receptor (EGFR) and epithelial cell adhesion molecule (EpCAM) to analyze their potency for diagnostic applications. Antigen expression was determined in primary tumors and LNs with and without metastases of 22 patients with PSCC. The total immunostaining score (TIS, 0–12) was determined as the product of a proportion score (PS, 0–4) and an intensity score (IS, 0–3). EGFR and VEGF expression were high in primary tumor (median TIS 8) and LN metastases (median TIS 6 and 8, respectively). No EGFR expression was seen in LNs without metastases. However, LNs without metastases did show VEGF expression (median TIS 6). No EpCAM or PSMA expression was seen in PSCC. This study shows that VEGF and EGFR expression is moderate to high in LN metastases of PSCC. Both VEGF and EGFR warrant further clinical evaluation to determine their value as a target for pre- and intraoperative imaging modalities in the detection of LN metastases in PSCC.

Robot-assisted endoscopic inguinal lymphadenectomy: A review of current outcomes

Objective

To review the role of robot-assisted endoscopic inguinal lymphadenectomy (RAIL) in the management of penile cancer.

Methods

A PubMed search for all relevant publications regarding RAIL series up until August 2019 was performed using the keyword “robotic”, “inguinal lymph node dissection”, and “penile cancer”. Weighted mean was calculated in the largest series for all outcomes using the number of patients included in each study as the weighting factor.

Results

We identified 23 articles, of note the three largest series that included 102, 27, and 20 RAIL in 51, 14, and 10 patients, respectively. Saphenous vein was spared in 88.93% of RAIL cases in these series and node yield was 11.42 per groin; 35.28% of patients had positive pathological nodes. The weighted mean of operative time was 87.98 min per RAIL and the estimated blood loss was 37.08 mL per patient. The mean length of hospital stay was 1.29 days and the drain was kept in place for 17.02 days; the major complication rate was only 5.31% in these series. The mean follow-up was 33.46 months with a recurrence-free survival of 96.33%.

Conclusion

The literature regarding RAIL describes promising results, although it has shorter follow-up and higher costs when compared to historically series from the open approach. Initials series reported lower cutaneous complications compared to conventional approach, without compromising oncological outcomes. However, long-term results and larger trials are crucial to validate those findings.

Nomogram prediction of overall survival based on log odds of positive lymph nodes for patients with penile squamous cell carcinoma

Purpose

This study aimed to establish a nomogram to predict the long‐term overall survival (OS) for patients with penile squamous cell carcinoma (PSCC).

Method

The PSCC patients receiving regional lymph node dissection (RLND) were enrolled from the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2015. The dataset of all eligible patients were used to develop the predictive model. The significant independent predictors were identified through Cox regression modeling based on the Bayesian information criterion and then incorporated into a nomogram to predicted 1‐, 3‐, and 5‐year OS. Internal validation was performed using the bootstrap resampling method. The model performance was evaluated using Harrell's concordance index (C‐index), calibration plots, integrated discrimination improvement (IDI), net reclassification improvement (NRI), and decision curve analysis (DCA).

Results

Totally, 384 eligible PSCC patients were enrolled from the SEER database. A nomogram for OS prediction was developed, in which three clinical variables significantly associated with OS were integrated, including age, N classification, and log odds of positive lymph nodes (LODDS). The C‐index of the nomogram (0.746, 95% CI: 0.702‐0.790) was significantly higher than that of the American Joint Committee on Cancer (AJCC) staging system (0.692, 95% CI: 0.646‐0.738, P = .020). The bootstrap optimism‐corrected C‐index for the nomogram was 0.739 (95% CI: 0.690‐0.784). The bias‐corrected calibration plots showed the predicted risks were in good accordance with the actual risks. The results of NRI, IDI, and DCA exhibited superior predictive capability and higher clinical use of the nomogram compared with the AJCC staging system.

Conclusion

We successfully constructed a simple and reliable nomogram for OS prediction among PSCC patients receiving RLND, which would be beneficial to clinical trial design, patient counseling, and therapeutic modality selection.