The Management of Regional Lymph Nodes in Patients with Penile Carcinoma and Reliability of Sentinel Node Biopsy

Role of Sentinel Lymph Node Biopsy in Clinically Node Negative Carcinoma Penis - a Prospective Study

Nodal metastasis is a strong prognostic indicator in carcinoma penis, with 25% difference in 5-year cancer-specific survival among node negative and node positive patients. This study aims to assess efficacy of SLNB in identifying occult nodal metastasis (seen in 20-25% of cases), thus avoiding morbidity of prophylactic groin dissection in rest. Study was conducted between June 2016 and December 2019 on 42 patients (84 groins). Primary outcomes assessed were sensitivity, specificity, false negative rates, positive predictive value, and negative predictive value of sentinel lymph node biopsy (SLNB) compared to superficial inguinal node dissection (SIND). Secondary outcomes were to know prevalence of nodal metastasis, sensitivity, specificity, false negative rates, positive predictive value (PPV), negative predictive value (NPV) of frozen section study, and ultrasonography (USG) compared to histopathological examination (HPE) and to evaluate false negative results of fine needle aspiration cytology (FNAC). Patients with impalpable inguinal nodes were subjected to USG and FNAC of suspicious nodes. Only those with non-suspicious USG/negative FNAC were included. Patients who were node positive, had prior chemotherapy/radiotherapy/prior groin surgery, or medically unfit for surgery were excluded. Dual-dye technique was used to identify sentinel node. Superficial inguinal dissection was done in all cases and both specimens were subject to frozen section. If ≥ 2 nodes were involved on frozen section, ilioinguinal dissection was done. SLNB had sensitivity, specificity, PPV, NPV, and accuracy of 100%, respectively. There were no false negative results of frozen section study among 168 specimens. Ultrasonography had sensitivity of 50%, specificity of 48.75%, PPV of 4.65%, NPV of 95.12%, and accuracy of 48.81%. We had 2 false negative results of FNAC. Sentinel node biopsy with frozen section study when done in properly selected cases using dual-dye technique in high volume centers by experienced professionals is a very reliable tool in establishing the nodal status, thereby facilitating need directed treatment, thus prevent either over/under treatment.

Predictors of inguinal lymph node metastasis in penile cancer patients: a meta-analysis of retrospective studies

Purpose

Inguinal lymph node metastasis (LNM) is one of the most significant prognostic factors for patients with penile cancer. This study aimed to identify potential predictors of inguinal LNM.

Patients and methods

A comprehensive search of the PubMed, Embase, and Cochrane Library databases for studies that reported predictors of inguinal LNM in penile cancer was performed. Finally, we selected 42 eligible studies with 4,802 patients. Accumulative analyses of odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were performed. All analyses were performed by using Review Manager software version 5.3.

Results

Among the 4,802 patients, 1,706 (36%) were diagnosed with inguinal LNM. Predictors of LNM included two categories: tumor-associated biomarkers and invasive clinicopathologic characteristics. Biomarker-specific predictors: the program death ligand 1 (PD-L1) overexpression (OR=2.55, p=0.002), higher neutrophil-to-lymphocyte ratio (NLR) (OR=4.22, p=0.010), higher C-reactive protein (CRP) (OR=4.78, p<0.001), squamous cell carcinoma antigen (SCC-Ag) overexpression (OR=8.52, p<0.001), P53 protein overexpression (OR=3.57, p<0.001). Clinicopathological predictors: positive clinical lymph node (cN+) (OR=5.86, p<0.001), high-risk histopathological subtype (OR=14.63, p<0.001) and intermediate-risk subtype (OR=3.37, p<0.001), vertical growth pattern (OR=1.97, p=0.020), higher stage (AJCC: OR=3.66, p<0.001; UICC: OR=2.43, p<0.001), higher tumor grade (OR=3.37, p<0.001), tumor size (>3 cm) (OR=2.00, p=0.002), LVI (OR=3.37, p<0.001), invasion depth (>5 mm) (OR=2.58, p=0.002), nerve invasion (OR=2.84, p<0.001), corpora cavernosum invasion (OR=2.22, p<0.001), corpus spongiosum invasion (OR=1.73, p=0.002) and urethra invasion (OR=1.81, p=0.030).

Conclusion

Current meta-analysis conclusively identified valuable predictors of inguinal LNM for patients with penile cancer. However, high-quality studies are warranted to further validate our conclusions. The intrinsic link between these predictors needs to be further investigated to create an accurate mathematical prediction model for LNM.

Beyond penile cancer, is there a role for sentinel node biopsy in urological malignancies?

This review aims to discuss the current state-of-the-art of sentinel node (SN) mapping in urological malignancies. The principles and methodological aspects of lymphatic mapping and SN biopsy in urological malignancies are reviewed. Literature search was restricted to English language. The references of the retrieved articles were examined to identify additional articles. The review also includes meta-analyses published in the past 5 years. SN biopsy for penile cancer is recommended by the European Association of Urology as the preferred staging tool for clinically node-negative patients with at least T1G2 tumours (level of evidence 2a, Grade B). The feasibility of SN biopsy in prostate cancer has been repeatedly demonstrated and its potential value is increasingly being recognised. However, conclusive prospective clinical data as well as consensus on methodology and patient selection are still lacking. For bladder, renal and testicular cancer, only few studies have been published, and concerns around high false-negative rates remain. Throughout the years, the uro-oncological field has portrayed a pivotal role in the development of the SN concept. Recent advances such as hybrid tracers and novel intraoperative detection tools such as fluorescence and portable gamma imaging will hopefully encourage prospectively designed clinical trials which can further substantiate the potential of the SN approach in becoming an integral part of staging in urological malignancies beyond penile cancer.

Minimal Invasive Management of Lymph Nodes

Penile cancer is a rare genitourinary malignancy. Lymph node involvement is the single most important factor determining survival in these patients, and those patients with occult disease are difficult to identify on conventional cross-sectional imaging. Until recently, lymph node sampling (eg, lymphadenectomy) has been the diagnostic modality of choice in the detection of micrometastasis. More recently, several novel molecular and minimally invasive diagnostic techniques have been developed, which have been demonstrated to decrease the false-negative and -positive results of conventional imaging and lymphadenectomy. This article focuses on the minimally invasive management of lymph nodes in men with penile cancer.

Elevated C-reactive protein values predict nodal metastasis in patients with penile cancer

Background

The nodal status is a strong predictor for cancer specific death in patients with penile carcinoma, and the C-reactive protein (CRP) level at diagnosis has recently been shown to be associated with poor clinical outcome in various solid malignancies. Therefore, this retrospective study was performed to evaluate the association between preoperative CRP levels and the incidence of nodal metastasis in patients with squamous cell carcinoma (SCC) of the penis.

Methods

The analysis included 51 penile cancer patients who underwent either radical or partial penectomy for pT1-4 penile cancer between 1990 and 2010. The nodal status was correlated with patient and tumor specific characteristics.

Results

Sixteen (31%) patients had lymph node metastasis at the time of penile cancer surgery. Nodal status was associated with tumor stage but did not correlate significantly with tumor grade. In contrast, high presurgical CRP levels were significantly associated with the diagnosis of nodal involvement (p = 0.04). The optimal CRP cut-off value to predict lymph node metastasis was set at 20 mg/l based on ROC analysis.

Conclusions

Since a high preoperative serum CRP level was closely correlated with nodal disease, it could be used as an additional marker to help identify patients with penile cancer who may benefit from inguinal lymph node dissection.

Accuracy of sentinel lymph node biopsy for inguinal lymph node staging of penile squamous cell carcinoma: systematic review and meta-analysis of the literature

PURPOSE

Sentinel lymph node biopsy is emerging as a promising method for inguinal lymph node staging of penile squamous cell carcinoma. In the current systematic review we evaluated the accuracy of sentinel lymph node biopsy for inguinal lymph node staging of penile squamous cell carcinoma and studied possible influential factors.

MATERIALS AND METHODS

MEDLINE®, Scopus®, ISI®, Ovid SP®, Springer, ScienceDirect® and Google™ Scholar were searched by the key words "(penile OR penis) AND sentinel". No date or language limitation was imposed on the search and meeting abstracts were not excluded from analysis. A random effects model was used for statistical pooling.

RESULTS

A total of 17 studies suitable for meta-analysis were detected. Three articles had 2 different subgroups of patients and each subgroup was considered as a separate study. Overall 18 studies (including the subgroups) were used for detection rate meta-analysis and 19 for sensitivity meta-analysis. The pooled detection rate was 88.3% (95% CI 81.9-92.6). Pooled detection rate of 90.1% (95% CI 83.6-94.1) was calculated for the studies using blue dye and radiotracer. The pooled sensitivity was 88% (95% CI 83-92). The highest pooled sensitivity (92% [95% CI 86-96]) was in the studies using radiotracer and blue dye, and recruiting only cN0 cases.

CONCLUSIONS

Sentinel lymph node mapping in penile squamous cell carcinoma is a method with a high detection rate and sensitivity. Using radiotracer and blue dye for sentinel lymph node mapping and including only cN0 disease ensures the highest detection rate and sensitivity.

Nodal staging in penile carcinoma by dynamic sentinel node biopsy after previous therapeutic primary tumour resection

BACKGROUND

Dynamic sentinel node biopsy (DSNB) is used to evaluate the nodal status of patients with penile carcinoma and clinically node-negative groins. This minimally invasive procedure is usually done at the same time as the treatment of the primary tumour.

OBJECTIVE

Our aim was to evaluate results of so-called postresection DSNB, that is, DSNB after previous resection of the penile tumour.

DESIGN, SETTING, AND PARTICIPANTS

All 40 patients who had undergone DSNB after previous penile carcinoma resection with histopathologically tumour-negative margins between February 2003 and July 2009 were analysed. Twenty patients (50%) had known unilateral nodal involvement, and DSNB was used to stage the clinically normal contralateral groin. Hence the study concerned 60 groins without palpable nodes. The median time between primary tumour resection and DSNB was 2.8 mo. The technique of postresection DSNB was similar to the standard procedure.

MEASUREMENTS

The sentinel node visualisation rate, identification rate, histopathologic results, and outcome during follow-up were investigated.

RESULTS AND LIMITATIONS

A sentinel node was visualised on the lymphoscintigrams of 56 of the 60 eligible groins (93%). A sentinel node was identified intraoperatively in all these 56 groins. A median of two sentinel nodes were removed. Histopathologic analysis revealed involvement of seven groins (12%) in seven patients (18%). The median size of these metastases was 6mm. Additional dissemination was found in one completed ipsilateral inguinal node dissection specimen. No recurrences developed in the groins from which one or more tumour-free sentinel nodes had been taken during a median follow-up of 28 mo after the primary tumour resection. A potential limitation of this study is the short follow-up and relatively small cohort number.

CONCLUSIONS

Postresection DSNB is a suitable procedure to stage clinically node-negative penile carcinoma after previous therapeutic primary tumour resection. The results seem similar to the favourable experience with DSNB in patients with their tumour still present.

Non-invasive and minimally invasive staging of regional lymph nodes in penile cancer

INTRODUCTION

The management of the regional lymph nodes in penile cancer patients, particularly when these lymph nodes are impalpable, remains controversial. Prophylactic bilateral inguinal lymphadenectomy is associated with high morbidity and is often unnecessary. However, there is no non-invasive or minimally invasive staging technique that can determine the lymph node status of penile cancer patients with 100% accuracy.

METHODS

We reviewed the current literature to examine the role of non-invasive and minimally invasive techniques for staging regional lymph nodes in penile cancer with particular reference to clinically impalpable disease.

RESULTS

Cross-sectional imaging (un-enhanced CT and MRI) modalities have a role in the assessment of patients with palpable inguinal basins and in locating distant metastases, but are unreliable in staging impalpable regional lymph nodes. The spatial resolution of lymphotropic nanoparticle enhanced MRI (LNMRI) and positron emission tomography (PET)/CT are limited to several millimetres and so these modalities cannot reliably detect micro-metastases (<2 mm). Ultrasound (US) and fine-needle aspiration cytology (FNAC) are indicated in staging palpable inguinal basins but are unreliable in isolation in the assessment of impalpable lymph nodes. They are, however, useful as an adjunct to dynamic sentinel lymph node biopsy (DSLNB) in lowering false-negative rates.

CONCLUSIONS

While we await staging modalities that can equal the results of DSLNB with fewer disadvantages, histological staging in the form of DSLNB remains the best minimally invasive staging modality we can offer at risk patients presenting with clinically node negative groins.