Reproducibility of histopathologic tumor grading in penile cancer—results of a European project

New histological risk grading system for prediction of lymph node metastasis in patients with penile cancer

Inguinal lymph node surgery is a standard treatment for penile cancer patients with intermediate or high risk for lymph node metastasis (LNM) according to European Association of Urology (EAU) risk grading. We are proposing a more objective histological prognostic grading system for inguinal LNM in these patients. We assessed worst pattern of invasion, lymphocytic host response, lymphovascular invasion, and perineural invasion in a population-based cohort of 306 penile cancer patients. Patients were classified into low, intermediate, and high risk for inguinal LNM. There was a significant association both between risk groups and pT stage (p < 0.001) and between risk groups and LNM. Univariate logistic regression showed 25.43 times higher odds of LNM for patients in the intermediate risk group compared with the low risk group (odds ratio (OR) 25.43; 95% confidence interval (CI): 5.94-108.97) and a 177.13 times higher odds in the high risk group compared to the low risk group (OR 177.13; 95% CI: 40.09-782.51). When comparing our histological risk grading with the EAU grading, we found a higher sensitivity, of 51.28% (95% CI: 45.68-56.88) versus 37.09% (95% CI: 31.68-42.50), as well as a higher area under the curve (0.86; 95% CI: 0.81-0.89; versus 0.65; 95% CI: 0.58-0.71) with our grading system. While our grading classified 111 patients as low risk, only 31 were considered low risk for LNM according to the EAU risk classification. The new histological risk grading system shows a higher sensitivity and includes a higher number of patients in the low risk group in whom lymph node surgery could be avoided, reducing morbidity and costs.

Global research trends in penile cancer: Bibliometric and visualized analysis

Background

Penile cancer is a malignant tumor of the genitourinary system that mostly occurs in middle-aged and elderly men aged 50-70 years, which can seriously affect physical, psychological, and sexual health. Hundreds of original articles and reviews on penile cancer are published each year. However, a bibliometric analysis of these publications has not been performed.

Objective

This study aimed to systematically analyze and visualize penile cancer-related publications through bibliometrics and reveal identified topics, hotspots, and knowledge gaps in related fields.

Methods

Based on the Web of Science core collection database, we first analyzed the quantity and quality of publications in the field of penile cancer. Second, we profiled the publishing groups in terms of country, institution, author's publication, and cooperation network. Then, we systematized and summarized the hot topics of research.

Results

This bibliometric analysis was conducted from 2001 to 2022. The analysis identified 1,687 articles and reviews, which were published in 432 journals. The number of publications and citations on penile cancer-related research has steadily increased over the last two decades. Furthermore, academic institutions in Europe and the United States play a leading role in penile cancer research. The country, institution, journal, and author with the most publications were the United States (507), H Lee Moffitt Cancer Research Center (96), Journal of Urology (83), and Spiess P (87), respectively. The most frequently used keywords were penile cancer (743), squamous-cell carcinoma (717), cancer (380), carcinoma (232), lymphadenectomy (229). 16 keyword clustering information was obtained, including #0 male circumcision, #1 lichen sclerosus, #2 chemotherapy, #3 penile neoplasms, #4 targeted therapy, #5 resection margin, #6 cervical cancer, #7 lymph node dissection, #8 prognostic factor, #9 prostate cancer, #10 inguinal lymph node dissection, #11 human papillomavirus DNA, #12 gene, #13 penile intraepithelial neoplasia, #14 male sexual function, and #15 penile cancer.

Conclusion

More and more scholars are devoted to the research on penile cancer. This bibliometric analysis revealed that the main research topics and hotspots in penile cancer included risk factors and surgical treatment plans.

Evaluation of the Cellular Dissociation Grading, Based on Tumor Budding and Cell Nest Size, in Squamous Cell Carcinoma of the Penis

The "Cellular Dissociation Grade" (CDG) is based on tumor cell budding and cell nest size. Many studies have examined the CDG in squamous cell carcinomas of other organs such as the lungs, oral cavity, pharynx, larynx, cervix and esophagus. In this study, the CDG was examined in 109 cases of invasive penile squamous cell carcinoma that were treated at the University Medicine Rostock between 2014 and 2022. Furthermore, its correlation with the pathologic status of regional lymph nodes (pN) as the main prognostic factor was verified. Finally, cellular dissociation grading was compared with classic WHO grading. The results showed that pN in penile squamous cell carcinoma showed a highly significant association with the CDG and no statistically significant association with WHO grading. These results support the notion that cellular dissociation grading is an important prognostic factor for squamous cell carcinoma.

Lymphovascular and perineural invasion are risk factors for inguinal lymph node metastases in men with T1G2 penile cancer

PURPOSE

To analyse the risk of inguinal lymph node (ILN) metastases in T1G2 penile cancer stratified by lymphovascular invasion (LVI), perineural invasion (PNI) and tumour size.

METHODS

Retrospective study of men with localised T1G2 penile cancer with non-palpable lymph nodes and no local recurrence during follow-up at six European institutional high-volume centres was performed. ILN involvement was defined as cancer detected during ultrasound-guided fine-needle aspiration cytology, core needle biopsy, dynamic sentinel lymph node biopsy, ILN dissection or inguinal recurrence during follow-up. Uni- and multivariable logistic regression analyses were performed.

RESULTS

In the cohort of 554 men with T1G2 penile cancer, from 6 European institutions, ILN metastases were observed in 46/554 men (8%, 95% confidence interval (CI) 6-11%). Men with both, LVI- and PNI- primary cancers had the lowest risk of ILN involvement (6%) whereas men with LVI + or PNI + showed ILN metastases in 22% and 30%. In multivariable regression, men with LVI + or PNI + had higher odds for ILN metastases compared to men with LVI- and PNI- (OR 3.9, 95% CI 1.6-9.0, p value < 0.01) Tumour size was not associated with ILN risk (OR 1.01 95% CI 0.99-1.04, p = 0.17).

CONCLUSION

Approximately, one out of ten men with T1G2 overall and one out of four men with either LVI + or PNI + still have ILN metastases despite being clinically node negative. Therefore, invasive ILN staging should strongly be recommended in T1G2 with LVI + or PNI + but importantly, must be discussed in patients with T1G2 with LVI- or PNI-.

Low level of interobserver concordance in assessing histological subtype and tumor grade in patients with penile cancer may impair patient care

Differentiation between penile squamous cell carcinoma patients who can benefit from limited organ-sparing surgery and those at significant risk of lymph node metastasis is based on histopathological prognostic factors including histological grade and tumor histological subtype. We examined levels of interobserver and intraobserver agreement in assessment of histological subtype and grade in 207 patients with penile squamous cell carcinoma. The cases were assessed by seven pathologists from three hospitals located in Sweden and Italy. There was poor to moderate concordance in assessing both histological subtype and grade, with Fleiss kappas of 0.25 (range: 0.02-0.48) and 0.23 (range: 0.07-0.55), respectively. When choosing HPV-associated and non-HPV-associated subtypes, interobserver concordance ranged from poor to good, with a Fleiss kappa value of 0.36 (range: 0.02-0.79). A re-review of the slides by two of the pathologists showed very good intraobserver concordance in assessing histological grade and subtype, with Cohen's kappa values of 0.94 and 0.91 for grade and 0.95 and 0.84 for subtype. Low interobserver concordance could lead to undertreatment and overtreatment of many patients with penile cancer, and brings into question the utility of tumor histological subtype and tumor grade in determining patient treatment in pT1 tumors.

The Clinical Complexity of Penile Cancer: Current Clinical-Epidemiological Data from the Database of the Free State of Saxony/Germany

OBJECTIVES

The aim of this study was to assess penile cancer incidence, clinical characteristics, treatment options, transparency of clinical quality, and relative survival based on data from the clinical cancer registry.

SUBJECTS AND METHODS

A total of 898 patients with tumours of the penis were diagnosed and analysed in the period from 2000 to 2018; they were documented in the 4 regional clinical cancer registries and summarized in the Command Office of these 4 registries.

RESULTS

The standardized incidence rate increased from 0.86 in 2000 to 2.67 in 2018. Most tumours were located at the glans (42.9%) followed by the prepuce (19.5%) and corpus penis (6.9%); they were classified into pT1a/pT1b (20.0%/7.0%), pT2 (23.5%), pT3 (12.4%), and pT4 (0.8%). In only 32.0% of all documented cases, a stage-related lymphadenectomy (LND) was carried out. Negative surgical margins were found in only 70% and the Rx status in 15.1%. Primary metastasis was detected in pN1 (5.1%), pN2 (3.9%), pN3 (3.1%), and M1 status in 3.0%, respectively. The predominant therapy was surgery in 78.3%. The proportion of penile partial resections was significantly (p = 0.0045) regredient over the control period. Adjuvant chemotherapy was performed in 4.7%, adjuvant external-beam radiotherapy in 3.0%. The 5-year relative overall survival rate was 74.7% and ranged from 108.0% (stage 0) to 17.1% (stage IV). A total of 29 hospitals performed tumour operations.

CONCLUSIONS

The multitude of clinical and epidemiological variables available in clinical cancer registries allows a safe assessment of tumour dynamics themselves, as well as good quality of transparency and broadly acceptable guideline adherence. Deviations from the accepted level of evidence were found in the grading definition, in the high quota of positive surgical margins, in the defensive indication position to the glans resurfacing/reconstruction and diagnostical LND. Based on these relevant findings in the database combined with the low frequency of the tumour in area/clinics/year, we recommended establishing SCCP reference clinics. This work is the first time that European standardized rate-based cancer registry data on penile cancer from Germany has been communicated.

[Conventional grading vs. molecular grading : Decision aids for clinical routine]

Conventional histopathological grading of a cancer is of utmost importance for the management and prognosis of the patient. Histopathological grading is predominantly a function of the differentiation and proliferation of tumor cells, the amount of necrosis present and the pattern of invasion. In addition, the molecular set-up of a given cancer which can be determined to some degree by immunohistochemistry or by methods analyzing genetic and epigenetic alterations can be used in some instances to improve the information gained by conventional histopathologic grading. Indeed, this latter option implies the promise of individualized tumor therapy. While this promise is on the horizon, the clinical implications for penile cancer are not yet transferable to individualized penile cancer treatment.

[Lesions of the penis, the anatomy, epidemiology and carcinogenesis]

The penile carcinoma is rare, but many items playing a role are complex and it is important to know as well the anatomy, but also the carcinogenesis for a perfect patient's management.

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

To determine the role of noninvasive, minimally invasive diagnostic modalities and current management recommendations for cN0 PNC, a literature review using PubMed and Web of Science search engines were conducted. We found that for predicting ILN+: physical exam has limitations, nomograms are not validated, conventional computerized tomography/magnetic resonance imaging/positron imaging tomography scans have minimal role, and dynamic sentinel lymph node biopsy is the most reliable minimally invasive modality. Adverse pathological features: G3, stage ≥ T2, presence of LVI, and rare histopathological variants are important predictors of ILN+ and their presence warrants prophylactic ILND or dynamic sentinel lymph node biopsy. In the absence of these adverse pathological features conservative management is justified.

Important Therapeutic Considerations in T1b Penile Cancer: Prognostic Significance and Adherence to Treatment Guidelines

BACKGROUND

The clinical implications and contemporary management of T1b penile cancer are unknown. National treatment guidelines advocate surgical lymph node examination (SLNE) for T1b disease.

OBJECTIVE

The aim of this study was to evaluate the prognosis of T1b disease and adherence to corresponding treatment guidelines.

METHODS

We analyzed 296 patients from two academic centers, and 1263 patients from the Surveillance, Epidemiology, and End Results (SEER) registry (median follow-up 48.3 and 21 months, respectively). Multivariate Cox and Fine-Gray regressions were applied for penile cancer-specific survival (PCSS) analyses.

RESULTS

In the academic center cohort, 28.3% of T1 patients had T1b disease, all of whom underwent SLNE. Nodal metastases were detected in 86.7% of T1b patients and 13.2% of T1a patients (p < 0.001). Using T1a as a reference, PCSS was significantly poorer in the T1b patients, with an adjusted hazard ratio (aHR) of 4.10 (p = 0.03). In the SEER cohort, 16.8% of T1 patients were classified as T1b. SLNE was performed in 21.7% of the T1b patients versus 38.2% of the T2 patients (p = 0.002). The probability of nodal metastases was 2.23-fold higher in T1b patients than in T1a patients (p < 0.001). In clinical N0M0 patients without SLNE, compared with T1a disease, T1b was associated with an aHR of 4.40 and a subdistribution HR of 4.53 for PCSS (both p = 0.003).

CONCLUSIONS

T1b penile cancer is strongly associated with nodal metastases and adverse PCSS, and is poorly managed according to guidelines recommended in the nationwide registry.

The Diagnosis and Treatment of Penile Cancer

BACKGROUND

The incidence of penile cancer in Europe lies in the range of 0.9 to 2.1 cases per 100 000 persons per year. Carcinogenesis is associated with human papilloma virus (HPV) infection and with chronic inflammation.

METHODS

This review is based on publications (2010-2017) retrieved by a selective search in PubMed and EMBASE and on the guidelines of the European Association of Urology, the European Society of Medical Oncology, the National Comprehensive Cancer Network, and the National Institute for Health and Care Excellence (NICE).

RESULTS

95% of cases of penile cancer are accounted for by squamous cell carcinoma, whose numerous subtypes have different clinical courses. Chronic preputial inflammation due to phimosis or lichen sclerosus is often associated with penile cancer. Circumcision lowers the risk of penile cancer (hazard ratio: 0.33). Maximally organ-preserving surgery with safety margins of no more than a few millimeters is the current therapeutic standard, because a local recurrence, if it arises, can still be treated locally with curative intent. Local radiotherapy can be performed in early stages. Lymphogenic metastasis must be treated with radical lymphadenectomy and adjuvant chemotherapy. Patients with clinically unremarkable inguinal lymph nodes nonetheless need invasive lymph node staging because of the high rate of lymphogenic micrometastasis.

CONCLUSION

Penile cancer is curable in all early stages with the appropriate treatment, but its prognosis depends crucially on the proper management of the regional (i.e., inguinal) lymph nodes. In many countries, the treatment of this rare disease entity has been centralized.

Contemporary management of patients with penile cancer and lymph node metastasis

Penile cancer is a rare disease that causes considerable physical and psychological patient morbidity, especially at advanced stages. Patients with low-stage nodal metastasis can achieve durable survival with surgery alone, but those with extensive locoregional metastasis have overall low survival. Contemporary management strategies for lymph node involvement in penile cancer aim to minimize the morbidity associated with traditional radical inguinal lymphadenectomy through appropriate risk stratification while optimizing oncological outcomes. Modified (or superficial) inguinal lymph node dissection and dynamic sentinel lymph node biopsy are diagnostic modalities that have been recommended in patients with high-risk primary penile tumours and nonpalpable inguinal lymph nodes. In addition, advances in minimally invasive and robot-assisted lymphadenectomy techniques are being investigated in patients with penile cancer and might further decrease lymphadenectomy-related adverse effects. The management of patients with advanced disease has evolved to include multimodal treatment with systemic chemotherapy before surgical intervention and can include adjuvant chemotherapy after pelvic lymphadenectomy. The role of radiotherapy in the neoadjuvant or adjuvant setting remains largely unclear, owing to a lack of high-level evidence of possible benefits. New targeted therapies have shown efficacy in squamous cell carcinomas of other sites and might also prove effective in patients with penile cancer.

Strong association of insulin-like growth factor 1 receptor expression with histologic grade, subtype, and HPV status in penile squamous cell carcinomas: a tissue microarray study of 112 cases

Insulin-like growth factor-1 receptor (IGF1R) plays a key role in cell growth and transformation. It is overexpressed in several solid tumors. This study evaluates IGF1R immunoexpression in penile squamous cell carcinoma (SCC). Four tissue microarrays were built from formalin-fixed, paraffin-embedded blocks of 112 penile SCC from Paraguay. Membranous IGF1R expression was evaluated by immunohistochemistry using two different approaches. An H-score was calculated in each spot (stain intensity by extent), and a median score per tumor was obtained. The second approach consisted of a score similar to the scoring system that was used for evaluating HER2 immunoexpression. For each case, the highest category obtained at any spot was used for statistical analyses. IGF1R expression was compared by histologic subtype, grade, and human papillomavirus (HPV) status. Median H-score was 22.5. The distribution of IGF1R expression by HER2 approach was as follows: 0 in 33.0% cases, 1+ in 46.4%, 2+ in 14.3%, and 3+ in 6.2%. IGF1R H-scores were associated with basaloid and warty/basaloid subtypes (p = 0.0026) and higher grade (p = 0.00052). Although weaker when using the HER2 approach, the association of IGF1R expression with subtype (p = 0.015) and grade (p = 0.015) remained significant. Furthermore, there was an association between IGF1R expression by HER2 approach and HPV status (p = 0.012). IGF1R was expressed in about two thirds of penile SCC cases, showing a strong positive association with histologic grade, subtype, and HPV status. Considering that grade is a predictor of outcome IGF1R expression may have prognostic relevance and could point to a potential role for IGF1R inhibitors in treating penile SCC.

Pathophysiological basis of human papillomavirus in penile cancer: Key to prevention and delivery of more effective therapies

Answer questions and earn CME/CNE Squamous cell carcinoma (SCC) of the penis is a rare malignancy in the United States, with a significantly higher incidence-up to 20 to 30 times greater-in areas of Africa and South America. This can be explained in part by the significantly greater prevalence of sexually transmitted diseases among high-risk males often having unprotected sex with multiple sexual partners. Human papillomavirus (HPV) has been implicated as the infectious pathway by which several these penile neoplasms originate from precursor lesions. In this regard, a fundamental understanding of HPV in penile carcinogenesis can have meaningful implications in understanding 1) the diagnosis of HPV-related precursor penile lesions, 2) targeting HPV-specific molecular pathways, and 3) cancer prevention. Using vaccination programs not only may improve patient outcomes but also may minimize the need for highly aggressive and often debilitating surgical resection. CA Cancer J Clin 2016;66:481-495. © 2016 American Cancer Society.

Pathologic Evaluation and Reporting of Carcinoma of the Penis

Carcinoma of the penis is a rare tumor in the United States and in western European countries. Clinical management has become more complex in recent years, because organ-preserving strategies are being favored. Furthermore, our understanding of the pathogenesis of this malignancy has grown considerably. As a result of these developments, the demands on the pathology reports of surgical specimens from the penis have increased. There are also some peculiarities with the current World Health Organization and TNM classification systems of penile cancer as compared with other tumor entities. This review outlines the most relevant aspects that have to be considered in the pathologic handling and typing of penile carcinoma.

The role of histologic subtype, p16(INK4a) expression, and presence of human papillomavirus DNA in penile squamous cell carcinoma

Background

Up to 50% of penile squamous cell carcinomas (pSCC) develop in the context of high-risk human papillomavirus (HR-HPV) infection. Most of these tumours have been reported to show basaloid differentiation and overexpression of tumour suppressor protein p16^INK4a. Whether HPV-triggered carcinogenesis in pSCC has an impact on tumour aggressiveness, however, is still subject to research.

Methods

In tissue specimens from 58 patients with surgically treated pSCC between 1995 and 2012, we performed p16^INK4a immunohistochemistry and DNA extraction followed by HPV subtyping using a PCR-based approach. The results were correlated with histopathological and clinical parameters.

Results

90.4% of tumours were of conventional (keratinizing) subtype. HR-HPV DNA was detected in 29.3%, and a variety of p16^INK4a staining patterns was observed in 58.6% of samples regardless of histologic subtype. Sensitivity of basaloid subtype to predict HR-HPV positivity was poor (11.8%). In contrast, sensitivity and specificity of p16^INK4a staining to predict presence of HR-HPV DNA was 100% and 57%, respectively. By focussing on those samples with intense nuclear staining pattern for p16^INK4a, specificity could be improved to 83%. Both expression of p16^INK4a and presence of HR-HPV DNA, but not histologic grade, were inversely associated with pSCC tumour invasion (p = 0.01, p = 0.03, and p = 0.71). However, none of these correlated with nodal involvement or distant metastasis. In contrast to pathological tumour stage, the HR-HPV status, histologic grade, and p16^INK4a positivity failed to predict cancer-specific survival.

Conclusions

Our results confirm intense nuclear positivity for p16^INK4a, rather than histologic subtype, as a good predictor for presence of HR-HPV DNA in pSCC. HR-HPV / p16^INK4a positivity, independent of histological tumour grade, indicates a less aggressive local behaviour; however, its value as an independent prognostic indicator remains to be determined. Since local invasion can be judged without p16^INK4a/HPV-detection on microscopic evaluation, our study argues against routine testing in the setting of pSCC.

[Organ-preserving therapy for penile carcinoma]

In recent years, a definite change towards organ-sparing, reconstructive local treatment of penile cancer has been observed. Surgical treatment aims to achieve margin-free resections with risk-adapted much smaller safety margins. Thus, the penile structures are preserved as far as possible or reconstructed in order to achieve a functionally and cosmetically satisfactory result. The oncological safety concerning tumor-free survival is not compromised. However, a higher rate of local recurrences has to be accepted.