Malignant Tumors of the Penis - Dia-gnostics and Therapy

BACKGROUND

Penile cancer belongs to group of relatively rare malignancies. It represents, on average, 0.5-1% of all tumours in males globally and occurs predominantly in older individuals (> 65 years). The geographical distribution of malignant cancer of the penis is reported. A higher incidence is observed in less developed parts of the world, particularly in South America, Southeast Asia, and some areas of Africa (> 2.0/100,000). In Slovakia, there has been a recent increase in incidence (1.1/100,000 in 2011). Mortality has stabilized at 0.3/100,000 in recent years. Significant risk factors for malignant cancers include social and cultural habits and hygienic and religious practices. Important risk factors are inadequate hygiene of the foreskin sac, phimosis, human papillomavirus infection, sexual promiscuity, smoking, genital infections, and a low socio-economic and educational status.

PURPOSE

The present paper provides an overview of pathology, symptomatology, diagnostic approaches, and classification of the extent of the disease. Treatment of the primary tumour depends on the extent of the disease and includes topical treatment, photodynamic treatment, cryoablation, laser photocoagulation, conservative surgical treatment, especially circumcision, and even radical treatment - penile amputation with perineal urethrostomy. An important part of the management of this malignancy is surgical treatment of metastases in inguinal lymph nodes. The article devotes more attention to non-surgical treatment modalities, in particular radiotherapy (external and brachytherapy) and systemic therapy (chemotherapy and biologic therapy), offering an overview of the indications and regimens in the adjuvant, neoadjuvant and palliative approaches, with and without concomitant chemoradiotherapy, and describes possible adverse effects of the treatments.  Conclusion: Patients with penile cancer should be concentrated in centres that have abundant experience in the diagnosis and treatment of this disease. Key words penile cancer - surgical treatment - radiotherapy - chemotherapy - biologic therapy The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 12. 11. 2018 Accepted: 12. 12. 2018.

Proposal for reclassification of N staging system in penile cancer patients, based on number of positive lymph nodes

In the present study, we aim to compare the rationality of proposed N classification based on the number of metastatic lymph nodes (LNs) with the current one. A total of 509 penile cancer patients at our institute were analyzed. Univariable and multivariable statistical analyses were used to assess cancer-specific survival (CSS) in 2 staging systems. Harrell's concordance index was applied to evaluate predictive accuracy of the current and proposed N classification in predicting CSS. We propose a new classification: pN1 (metastasis in 1-2 regional LNs), pN2 (metastasis in 3 regional LNs, or 3 or fewer regional lymph nodes with extranodal extension), and pN3 (metastasis in 4 or more regional LNs). According to the current and proposed N classification, the 5-year CSS of penile cancer patients with pN1, pN2 and pN3 was 85.8%, 39.0%, and 19.7%; and with pN1, pN2 and pN3 was 79.8%, 39.3% and 15.3%, which almost all showed significant difference (P < .001, P = .259) (P < .001, P < .001). Multivariable predictive accuracy of the proposed and current N staging was 76.48% and 70.92% (5.56% gain; P < .001). With a multivariable model of clinical features, both current (hazard ratio [HR], 7.761, 10.612; P < .001, P < .001) and proposed N stages (HR, 3.792, 3.971; P < .001, P < .001) exhibited independent effects on survival. The proposed N classification is superior to the current one, which is simpler and provides more accurate prognosis.

Epithelial Lesions Associated with Invasive Penile Squamous Cell Carcinoma: A Pathologic Study of 288 Cases

A heterogeneous spectrum of epithelial alterations and atypical lesions affect the squamous epithelium of penile mucosal anatomical compartments. Analogous to other genital sites, the terminology utilized to define the lesions is variable. The few pathologic studies of penile precancerous lesions are mostly related to carcinoma in situ and human papilloma virus (HPV), and the information on low-grade atypical lesions is limited. The objective of this study was to comprehensively describe the morphologic features of all epithelial alterations, benign and atypical, low grade and high grade, associated with invasive squamous cell carcinoma of the penis and to investigate their relation with each other and with subtypes of invasive carcinoma. We also propose herein a simple and reproducible nomenclature for penile precancerous abnormalities until more biological, molecular, or epidemiologic information on the lesions is available. Two hundred and eighty-eight penectomy and circumcision specimens with invasive squamous cell carcinoma were pathologically evaluated. Carcinomas were classified as usual, verrucous, papillary not otherwise specified, warty (condylomatous), basaloid, and mixed. Associated lesions were classified as squamous hyperplasia and squamous intraepithelial lesions of low and high grade (LGSIL and HGSIL). In LGSIL, atypia was confined to the lower third, and in HGSIL, atypical cells affected at least two thirds of the squamous epithelium. Subtypes of SIL were squamous, warty, basaloid, warty-basaloid, and papillary. Squamous hyperplasia, the most common lesion, was found in 83% of the cases, followed by LGSIL (59%) and HGSIL (44%). In 62% of the cases more than 1 associated lesion was present per specimen. A sequence from squamous hyperplasia to low-grade to high-grade SIL was seen frequently. Squamous hyperplasia was more commonly associated with usual squamous, papillary, and verrucous than with warty and basaloid invasive carcinomas. LGSIL was associated with all types of squamous cell carcinoma but was rarely present adjacent to basaloid or verrucous tumors. HGSIL was present in two thirds of invasive warty, basaloid, and mixed warty-basaloid tumors, in about half of usual squamous cell carcinomas, and was absent in papillary and verrucous carcinomas. Correlation of special types of invasive carcinomas with subtypes of SIL revealed morphologic correspondence of invasive tumor and the associated intraepithelial lesion. Squamous LGSIL was preferentially associated with verrucous, papillary, and usual squamous cell carcinomas; warty LGSIL, with invasive warty and mixed wartybasaloid carcinomas. High-grade SIL of the squamous type was frequently found in squamous cell carcinoma of usual type but was rarely present with warty or basaloid carcinomas. Basaloid HGSIL was associated with basaloid carcinoma, and HGSIL of warty type, with either warty or mixed warty-basaloid carcinomas. The high frequency of squamous hyperplasia and LGSIL and preferential association with usual, verrucous, and papillary carcinomas plus the subtle morphologic differences of the 2 lesions suggest that, despite its benign appearance, squamous hyperplasia is a precursor of the aforementioned carcinomas. The association and histologic similarities between high-grade SIL of the basaloid, warty, or mixed forms with their invasive counterparts indicate these lesions are their likely precursors.

Review of in situ and invasive penile squamous cell carcinoma and associated non-neoplastic dermatological conditions

Penile carcinoma is a rare genitourinary malignancy in North America and Europe with highest rates recorded in South America, Africa and Asia. Recent classifications have refined the terminology used in classifying intraepithelial/in situ lesions and additionally newer entities have been recognised in the invasive category. While increasing recognition of a bimodal pathway of penile carcinogenesis has facilitated understanding and classification of these tumours, handling and subtyping of penile malignancies presents a challenge to the reporting pathologist, in part due to their rarity. This article reviews the terminology and classification of in situ and invasive carcinomas and their relationship to human papilloma virus status. In addition, associated non-neoplastic dermatological conditions of relevance and appropriate ancillary investigations will be addressed.

[Penile squamous cell carcinoma]

Penile squamous cell carcinoma (SCC) is uncommon in Europe, where it accounts for approximately 0.7% of all malignant tumors in men. The main risk factors are poor hygiene, lack of circumcision, human papillomavirus (HPV) infection, and certain chronic inflammatory skin diseases. HPV infection is detected in 70% to 100% of all penile in situ SCCs and in 30% to 50% of invasive forms of the disease, mainly basaloid and warty SCCs. In situ tumors can be treated conservatively, but close monitoring is essential as they become invasive in between 1% and 30% of cases. The treatment of choice for penile SCC is surgery. Inguinal lymph node irradiation is no longer recommended as a prophylactic measure, and it appears that selective lymph node biopsy might be useful for reducing the morbidity associated with prophylactic inguinal lymph node dissection. Survival is directly related to lymph node involvement. Improving our knowledge of underlying molecular changes and their associated genotypes will open up new therapeutic pathways.

Shortcomings of the current TNM classification for penile carcinoma: time for a change?

INTRODUCTION

Accurate tumor staging is essential in the management of malignancies. It provides a guide in selecting accurate treatment and gives an indication of prognosis based on the extent of disease. The current TNM classification for penile carcinoma has remained unchanged since 1987. In this article, we focus on several deficiencies of the current classification.

MATERIALS AND METHODS

An analysis of the current literature regarding the current classification was done, focusing on known prognostic factors for survival. Furthermore, we discuss in detail the results from a recent analysis of more than 500 patients treated at our institute to evaluate the practical and prognostic value of the TNM-classification.

RESULTS

We found that, using the current classification system, accurate clinical staging is often difficult, because the T and N categories are defined by structures that are not easily identified using physical examination or imaging. Furthermore, the prognostic stratification of the present staging system is not optimal and there is a substantial overlap in disease-specific survival between several categories. We give an overview of modifications that could improve clinical staging and prognostic ability.

CONCLUSION

The current TNM classification for penile carcinoma has several shortcomings in terms of usability in clinical staging and prognostic value. With modifications clinical staging is facilitated, while the prognostic stratification of the classification is improved.

18F-FDG PET/CT for staging of penile cancer

The value of PET or PET/CT with (18)F-FDG for the staging of penile cancer has yet to be determined. The objective of this study was to investigate the pattern of (18)F-FDG uptake in the primary malignancy and its metastases and to determine the diagnostic value of (18)F-FDG PET/CT in the staging and restaging of penile cancer.

METHODS

Thirteen patients (mean +/- SD age, 64 +/- 14.0 y) with suspected penile cancer or suspected recurrent disease were examined with a Gemini PET/CT system (200 MBq of (18)F-FDG). The reference standard was based on histopathologic findings obtained at biopsy or during surgery.

RESULTS

Both the primary tumor and regional lymph node metastases exhibited a pattern of (18)F-FDG uptake typical for malignancy. Sensitivity in the detection of primary lesions was 75% (6/8), and specificity was 75% (3/4). On a per-patient basis, sensitivity in the detection of lymph node metastases was 80% (4/5), and specificity was 100% (8/8). On a nodal-group basis, PET/CT showed a sensitivity of 89% (8/9) in the detection of metastases in the superficial inguinal lymph node basins and a sensitivity of 100% (7/7) in the deep inguinal and obturator lymph node basins. The mean +/- SD maximum standardized uptake value for the 8 primary lesions was 5.3 +/- 3.7, and that for the 16 lymph node metastases was 4.6 +/- 2.0.

CONCLUSION

According to our results, the main indication for (18)F-FDG PET in the primary staging or follow-up of penile cancer patients may be the prognostically crucial search for lymph node metastases. With the use of a PET/CT unit, the additional information provided by CT may be especially useful for planning surgery. Implementing (18)F-FDG PET and PET/CT in future staging algorithms may lead to a more precise and stage-appropriate therapeutic strategy. Furthermore, invasive procedures with a high morbidity rate, such as general bilateral lymphadenectomy, may be avoided.

Limitations in the interpretation of biopsies in patients with penile squamous cell carcinoma

Surgeons often perform small or superficial penile biopsies that are difficult to classify definitely with regard to a benign or malignant nature, and if malignant, cannot always be accurately subclassified. Staging and therapeutic decisions rely on the identification, in these materials, of pathologic parameters related to prognosis. In this study, we evaluated the accuracy and completeness of pathologic information obtained from biopsies of 57 consecutive patients with squamous cell carcinoma (SSC) of the penis, and compared it with the information obtained from penectomies. Diagnostic accuracy was determined by recording discordances of critical factors in biopsies and penectomies. The evaluated parameters were as follows: cancer diagnosis, histologic type, tumor grade, depth of invasion (anatomical levels), and vascular invasion. Histologic subtypes of SCC were the following: usual 37, verruciform 11, mixed 7, pseudohyperplastic 1, and sarcomatoid 1. Grades were 1, 2, and 3 (well, moderately and poorly differentiated). Levels of invasion were lamina propria, corpus spongiosum, and corpus cavernosum in the glans; and lamina propria, dartos, and skin in the foreskin. In 2 patients with well-differentiated tumors a diagnosis of cancer could not be established in biopsy material. In 17 cases (30%) there was a biopsy-penectomy discordance of histologic types, especially of verruciform and mixed carcinomas. Biopsies failed to identify the correct histologic grade in 30% of the cases. A higher grade was usually identified in penectomy specimens. Because biopsies were superficial, the deepest point of invasion could not be determined in 91% of the cases. Vascular invasion was identified in biopsies in only 1 of 8 patients. In summary, biopsies were useful for cancer diagnosis except in 2 differentiated variants of penile squamous cell carcinoma. However, important pathologic parameters related to prognosis were missed on biopsy materials, and they were more accurately evaluated in penectomy specimens. We conclude that clinical and pathologic staging of penile cancer, at least in our material, cannot depend on biopsy information alone. Data from biopsies may be insufficient to make a decision whether to perform a groin dissection, or for prognostic evaluation in those patients in whom other treatment modalities (such as radiotherapy or chemotherapy) are being considered.

Genital human papillomavirus infection and associated penile intraepithelial neoplasia in males infected with the human immunodeficiency virus

OBJECTIVE

To investigate the association between human papillomavirus (HPV) infections and penile intraepithelial neoplasia (PIN) in genital lesions from human immunodeficiency virus (HIV)+ men. For comparison, we also investigated the same association using specimens from HIV- men.

STUDY DESIGN

Imprint smears from penile lesions were obtained from 70 men (mean age, 30 years) who visited a dermatologist. Thirty of them were known to be HIV seropositive. Two study groups were formed: one of 40 HIV- and another of 30 HIV+ males. The smears were examined cytologically for HPV identification or PIN, immunocytochemically for HPV detection and by in situ hybridization for HPV typing.

RESULTS

The rates of detecting HPV infection cytologically were higher among men with HIV infection (50%) than among their HIV-seronegative counterparts (30%). There was immunocytochemical evidence of HPV in HIV-infected men in a greater proportion (50%) than in HIV noninfected men (37.5%). By in situ hybridization it was found that there was a higher prevalence of potentially oncogenic HPV (16/18, 31/33/35): 75% in moderate or severe dysplasia (PIN 2 and 3) and 66.6% in HIV+ men as compared with HIV- men (10-16.6%).

CONCLUSION

HIV-seropositive males showed an unbalanced distribution of HPV, with a predominance of "high-risk" HPV types. This suggests that immunodepression encourages infection by this oncogenic virus, thereby contributing to the frequency of precancerous lesions in HIV+ men.

Warty (condylomatous) squamous cell carcinoma of the penis: a report of 11 cases and proposed classification of 'verruciform' penile tumors

Within the spectrum of penile squamous cell carcinomas, those that we descriptively refer to collectively as the "verruciform" lesions are particularly difficult to subclassify. In a review of 50 such tumors, we found 11 distinctive neoplasms with condylomatous features conforming to the appearance of so-called "warty (condylomatous) carcinoma." The average patient age was 55 years and the average duration of disease was 19 months. The primary tumor involved multiple anatomic sites (glans, coronal sulcus, and foreskin) in seven cases and a single site (glans or foreskin) in four cases. Grossly, white to gray cauliflower-like tumors typically measuring approximately 5 cm were noted. Histologically the tumors were mainly papillomatous with acanthosis and hyperkeratosis. The papillae had prominent fibrovascular cores. The most conspicuous microscopic findings were striking nuclear atypia of koilocytotic type and clear cytoplasm. The interface between tumor and stroma was irregular in the majority of cases; deep invasion of corpus cavernosum was noted in five cases. The differential diagnosis included verrucous carcinoma, low-grade papillary squamous cell carcinoma, not otherwise specified, and giant condyloma acuminatum. Among other differences, the first two lesions show no koilocytotic changes and the last lacks malignant features and irregular stromal invasion. Metastatic spread occurred in two patients; both are alive with evidence of recurrent disease 12 and 72 months after initial diagnosis. A third patient was alive with recurrent disease 12 months after diagnosis. Five patients were free of disease 8, 12, 24, 52, and 108 months after diagnosis. Three patients were lost to follow up. Warty (condylomatous) carcinomas of the penis are morphologically distinctive verruciform neoplasms with features of human papillomavirus-related lesions and should be distinguished from other verruciform tumors so that differences in behavior, if any, between these tumors will become established.

Molecular pathology and clinicopathologic features of penile tumors: with special reference to analyses of p21 and p53 expression and unusual histologic features

OBJECTIVES

To examine the histologic features of p21 in penile tumors and to determine the role of p21 and p53 in the pathogenesis of this group of tumors.

METHODS

The clinicopathologic features of 87 patients with penile tumors were studied. The expression of p53 and p21 proteins in 49 cases was investigated by immunohistochemistry.

RESULTS

Of the 87 tumors studied, 84 represented primary penile tumors (72 malignant and 12 benign) and 3 represented secondary tumors (2 from bladder, 1 from nasopharynx). The primary malignant penile tumors included 66 surface carcinomas with squamous differentiation (92%), 3 cases of Paget disease (4%), 1 case of Bowen disease (1%), and 2 penile urethral squamous cell carcinomas (3%). The former group was subdivided into squamous cell carcinoma (n = 50), verrucous carcinoma (n = 8), basaloid squamous cell carcinoma (n = 3), adenoid squamous cell carcinoma (n = 3), spindle cell carcinoma (n = 1), and adenosquamous carcinoma (n = 1). The benign tumors were squamous cell papillomas (n = 10) and fibromatoses (n = 2). Expression of p21 and p53 was noted in 40% and 89%, respectively, of the 47 patients with primary surface penile carcinoma with squamous differentiation. Positive p21 and p53 expression was also seen in 2 cases of Paget disease. Staining for p21 was often weak and was found in the suprabasal region of carcinomas with squamous differentiation, while p53 expression was seen in the basal region of squamous cell carcinomas. Preinvasive lesions also showed p21 and p53 expression. An inverse correlation between p53 and p21 expression (p53(+)/p21(-) or p53(-)/p21(+)) was noted in half of the squamous cell carcinomas, 4 of 5 verrucous carcinomas, 2 of 3 basaloid squamous cell carcinomas, and in 1 spindle cell carcinoma. The other cases did not show this correlation.

CONCLUSIONS

Penile tumors had different histologic variants and p21/p53 expression patterns. Expression of p21 did play a role in some tumors and could be dependent or independent of p53 expression.

[Carcinoma of the penis. The basic principles of the diagnostic and therapeutic guidelines]

Despite the low incidence of penile cancer nowadays, this tumor presents a difficult diagnosis and staging methodology as well as difficult therapeutic options. The author emphasises the clear destruction between superficial and invasive neoplasms. In the latter, the simultaneous treatment of the lymphatic territories is considered of extreme importance.

Squamous cell carcinoma of the penis

Penile tumors, although not frequent, represent a difficult diagnostic and therapeutic challenge. Of the malignant penile neoplasms, the most frequent is penile carcinoma, which includes squamous cell carcinoma and its well-differentiated variant, verrucous carcinoma. Current concepts about classification, epidemiology, pathogenesis, histopathology, diagnosis, staging, prognosis, and treatment are presented.

Verrucous carcinoma of the genital tract: is it a distinct entity?

Between 1974 and 1985, 16 patients (7 men, 9 women) with a diagnosis of genital verrucous carcinoma were identified from the cancer registry of the Tom Baker Cancer Centre in Calgary. All the men had lesions on the penis. In the women, five lesions were on the vulva, four were on the cervix and two were on the vagina (two women each had two involved sites). The histologic slides from the surgically excised specimens were reviewed, and, by applying strict criteria, all cases could be reclassified as giant condyloma (five cases), intraepithelial neoplasia with or without condylomatous features (eight cases) or invasive squamous cell carcinoma (five cases). The authors believe that, in genital lesions associated with the human papillomavirus, a diagnosis of verrucous carcinoma is nonspecific and may lead to inappropriate clinical management.

[Chemotherapy of penile carcinomas]

The value of chemotherapy in treatment of squamous epithelial carcinoma of the penis is still uncertain, and its clinical relevance is speculative. In locally delimited carcinoma (T1, T2), partial penectomy is still the first-line therapy, and the alternatives of bleomycin monotherapy or combination therapy with bleomycin and radiation should be applied only when patients rigorously reject surgery. The prospects of success are rather uncertain with these forms of treatment. Palliative chemotherapy for metastasized carcinoma has so far yielded data indicating that methotrexate administration is of therapeutic benefit, even if only for a short time. Elaborate multiple combinations must be considered critically, especially because of the appreciable burden on the patient, a rate of response that in the final analysis is still uncertain, and the small number of cases treated so far.

Transplantation characteristics, morphologic features, and interpretation of preputial gland neoplasia in the Fischer 344 rat

Preputial gland neoplasms in the Fischer 344 rat are relatively uncommon tumors with a prevalence of approximately 3% in the National Toxicology Program data base. They occur late in life, are well differentiated, and rarely metastasize. Based on studies through 4 serial passages, 10 well-differentiated preputial gland neoplasms transplanted into the mammary fat pads of syngeneic recipients grew to 30 mm within 10 weeks. Recipients died or were sacrificed with large transplanted tumors within 6 months. The morphologic features of the transplanted neoplasms were similar to those of the primary neoplasms through the four passages. Proliferative lesions of the preputial glands comprise a morphological continuum and separation of these growths into categories of hyperplasia, adenoma, and carcinomas is based largely on cytological features and the degree of altered growth patterns. Morphologic features to assist in diagnosis of preputial gland neoplasms and recommendations for interpreting treatment-associated increases of these neoplasms are presented.

Morphology of hyperplastic and neoplastic lesions in the clitoral and preputial gland of the F344 rat

We reviewed 359 neoplasms of the preputial and clitoral glands of F344 rats to classify the different types of tumors, in relation to the normal anatomy and histology of the glands. Most tumors originated from the acinar or ductal cells; only one tumor originated from mesenchymal tissue. They were classified as adenomas, adenocarcinomas, squamous cell or basal cell carcinomas, and mixed cell carcinomas. Only one tumor metastasized to the lung.

On the classification of penis carcinoma and its 10-year survival

With respect to the primary tumor there is no difference between the proposal of the UICC and the Heidelberg version for TNM classification of the penis carcinoma. Clinically the Heidelberg scheme seems more practical, but there were no statistical differences between them. With respect to the prognosis for the patient, the size and localization of the primary tumor are of secondary importance. What is important is the degree of tumor spreading in the lymph system. From this point of view, one needs only to differentiate between T1 (tumor restricted to the penis) and T2 (tumor extending the bounds of the penis). On the other hand, size, localization, and degree of infiltration of penis carcinoma do have different therapeutic consequences, so from this point of view the differentiation of the primary tumor from T1 up to T4 should be retained. With respect to the classification of the state of the corresponding lymph system it is our opinion that the UICC proposal is too differentiated and has little meaning. In its stead, the Heidelberg scheme is clear and simple. Any examiner can complete it. With the help of life tables extending beyond 10 years after diagnosis we were able to determine that 5 years is not a sufficiently long time to clsoe a case of penis cancer. Even with proper treatment, the patient may suffer up to 10 years or more from the disease. In patients aged between 50 and 59 years of age the cancer seems to grow faster; in spite of proper and intensive treatment those patients had a clearly limited life expectancy. In patients aged 60-69 and more so in those between 70 and 79 years of age the tumor seemed to grow slowly and often had no effect on the survival rate.