RECENT ADVANCES IN IMAGING STUDIES FOR STAGING OF PENILE AND URETHRAL CARCINOMA

A 25-year perspective on advances in an understanding of the biology, evaluation, treatment and future directions/challenges of penile cancer

Squamous cell carcinoma of the penis (SCCP) is uncommon in some countries (including the U.S.), but is an important malignancy elsewhere. As a rare disease, progress has been slow compared to more common tumor types discussed in this anniversary issue and most often limited to single-center or retrospective datasets.  In this section we describe developments leading to the current standard approach with current research questions.

MRI of common penile pathologies and penile prostheses

MRI can delineate finer details of penile anatomy and pathology due to inherent higher soft-tissue contrast and spatial resolution. It can characterize inflammation and identify abscesses, localize penile fractures, guide surgical planning in penile fibrosis and Peyronie's disease, and depict components of the penile prosthesis and its complications. MRI is a great investigative tool for penile neoplasms, including locally infiltrative neoplasms where clinical examination is limited, and local staging is crucial for surgical planning.

Primary Adenocarcinoma of the Urethra: A Case Report and Review of the Literature

Primary adenocarcinoma of the urethra is rarely reported. We report a case of a 47-year-old male with symptoms of urinary obstruction started 2 years before diagnosis. Video-assisted urethrocystoscopy revealed a papillary mass almost obstructing the entire lumen with bleeding. Pathology report was consistent with primary adenocarcinoma of the urethra.

Magnetic resonance imaging of solid urethral and peri-urethral lesions

Solid urethral and peri-urethral lesions are rare and encompass benign and malignant aetiologies. A diagnosis without imaging is often challenging secondary to non-specific clinical symptoms and overlapping findings at the time of physical examination. Magnetic resonance (MR) imaging may be helpful in confirming a diagnosis while providing anatomical detail and delineating disease extent. This article reviews the normal MR anatomy of the male and female urethra, the MR appearance of solid primary and secondary urethral lesions, and the MR appearance of solid urethral lesion mimics.

Teaching points

• MRI is an important imaging technique in the evaluation of the spectrum of solid urethral lesions.

• With excellent soft tissue resolution, MR is accurate in staging primary urethral carcinoma.

• Disruption of the zonal anatomy of the female urethral wall indicates peri-urethral extension.

• Be aware of benign urethral lesions, particularly those that may mimic solid urethral masses.

Imaging of unusual perineal masses

OBJECTIVE

The purpose of this article is to describe the radiologic features of unusual tumors that occur in the perineum.

CONCLUSION

The perineal space is often overlooked because of the infrequency of abnormalities. Accurate image interpretation and visualization of extent of pathology is important for proper management. Trauma and infectious diseases occur in the acute setting, whereas tumors are common in the chronic setting. Cross-sectional imaging plays a crucial role in depicting perineal anatomy and evaluating the extent of disease.

Non-surgical treatment of primary female urethral cancer

Primary carcinomas of the female urethra are extremely rare, with an annual incidence of less than ten in one million. Currently, there is no consensus regarding management of this malignancy. However, there have been several case reports demonstrating the efficacy of chemoradiation in the treatment of female urethral cancer. In this report we present two cases of female primary urethral adenocarcinoma that were treated by concomitant chemotherapy and external beam radiotherapy, followed by interstitial brachytherapy.

[Metastasic urethral squamous-cell a cancer]

Urethral cancer is an infrequent pathology, less than 1% of the genitourinary tumors. It is more frequent in women (4:1), in the sixth or seventh decade of life. The most frequent histology being squamous cell carcinoma. First signs and symptoms usually are more attributable to benign stricture disease, rather than malignicy. The interval between the onset of symptoms and diagnosis may be as long as three years. Therefore most of these tumors are locally advanced at the time of diagnosis with generally poor prognosis despite aggressive treatment. Therapeutic management varies with the stage and location of the lesion. Because of the rarity of this pathology, no consensus has been reached on treatment modalities, but seems to be that must be a multimodal one, including surgery, radiotherapy and chemotherapy. We present the case of an 80 year-old male, with a diagnosis of urethral squamous-cell cancer, locally advanced at the time of diagnosis. Surgery was not feasible. The patient underwent chemotherapy and radiotherapy with evidence of quick progression thereafter.

[Metastases from squamous cell carcinoma of the penis]

Penile cancer is a rare carcinoma and visceral metastases are uncommon. Metastasis diagnosis is carried out with TDM and MRI but markers can sometimes be helpful (ie SSCAg). There is no referent chemotherapy, a trial has been started (CAVER).

Imaging of penile neoplasms

The assessment of penile cancer on the basis of clinical findings alone can often result in inaccurate staging and suboptimal treatment. Imaging of primary penile cancer and metastatic lymphadenopathy can help optimize planning of both primary tumor resection and treatment for lymph node metastases. Magnetic resonance (MR) imaging is the most accurate imaging modality in the assessment of primary penile cancers, which usually manifest as solitary, ill-defined infiltrating tumors that are hypointense on both T1- and T2-weighted MR images. T2-weighted MR imaging allows delineation of the tumor margin and of any extension into the penile shaft. On gadolinium-enhanced T1-weighted images, the tumors enhance to a greater extent than do the corpora cavernosa. In addition, the recently introduced technique known as lymphotrophic nanoparticle-enhanced MR imaging can help identify metastatic lymph node disease. However, further studies will be needed to determine the role of this imaging technique in clinical practice. Computed tomography does not clearly depict the local extension of primary penile cancer; however, it is useful in assessing metastases and postoperative complications.

Penile cancer

Penile cancer, while relatively rare in the western world, remains a disease with severe morbidity and mortality, not to mention significant psychological ramifications. Furthermore, the disease is observed with dramatically increased incidence in other parts of the world. A review of the literature has shown that the overwhelming majority of penile cancers are in situ or invasive squamous cell carcinomas, including a well-differentiated variant, verrucous carcinoma. Important predisposing factors are lack of circumcision, human papillomavirus infections, and penile lichen sclerosus, although other factors have occasionally been reported as well. Prevention, careful monitoring of patients at risk, and early diagnosis are essential to reduce the incidence of penile carcinoma and to provide a definitive cure. Public health measures, such as prophylactic use of circumcision, have proved successful but are controversial. Also, no standard therapeutic guidelines as to the best treatment strategy according to different stages, including efficacy of conservative nonsurgical modalities and indications for lymph nodal dissection, are available so far. It is common opinion that penile cancer is an emerging problem that deserves further investigations, and physicians, especially dermatologists, should be aware of this issue.

LEARNING OBJECTIVE

At the completion of this learning activity, participants should be familiar with penile carcinoma, its risk factors, its clinical and histologic presentation, and the treatments currently available for its management.

Imaging of urethral disease: a pictorial review

Retrograde urethrography and voiding cystourethrography are the modalities of choice for imaging the urethra. Cross-sectional imaging modalities, including ultrasonography, magnetic resonance (MR) imaging, and computed tomography, are useful for evaluating periurethral structures. Retrograde urethrography is the primary imaging modality for evaluating traumatic injuries and inflammatory and stricture diseases of the male urethra. Sonourethrography plays an important role in the assessment of the thickness and length of bulbar urethral stricture. Although voiding cystourethrography is frequently used to evaluate urethral diverticula in women, MR imaging is highly sensitive in the demonstration of these entities. MR imaging is also accurate in the local staging of urethral tumors.

Cancer of the penis

Cancer of the penis is rare in Europe, accounting for less than 0.5% of all cancers. Phimosis and poor hygiene are strong risk factors whereas neonatal circumcision is a contributing factor in the prevention of this disease. More than 95% of penile carcinomas are squamous cell carcinomas. Early disease (stage I-II) is curable in most patients, who can be treated by conventional penile amputation or, in selected cases, by organ preserving techniques, including Moh's micrographic surgery, laser ablation or radiation therapy (external-beam, brachytherapy). For more advanced primary tumours, penile amputation is required. Survival of patients with penile cancer is strongly related to the presence and extent of nodal metastases. Bilateral inguinal lymphadenectomy is recommended for palpable lymph nodes that persist 3 or more weeks after removal of the primary tumour and a course of antibiotic therapy. In patients with proven inguinal lymph node metastases, bilateral ileoinguinal dissection should be performed. When the nodes are clinically negative, "prophylactic" inguinal lymphadenectomy may be a reasonable approach in patients with invasive tumours (T2 or greater), high grade tumours, or tumours exhibiting vascular invasion. The role of chemotherapy, as adjuvant and neoadjuvant or primary treatment in metastatic disease, needs to be further explored in prospective clinical trials.

Penile carcinoma: a challenge for the developing world

Although rare in developed countries, carcinoma of the penis is an important problem in the developing world. Circumcision done in childhood offers the greatest protection against this disease. Poor penile hygiene and phimosis are strong risk factors for development of penile carcinoma. Early disease can be treated by conventional resection of the penis, or in selected patients by organ preserving techniques including Mohs micrographic surgery, and laser and radiation therapy. For more advanced primary disease, partial or total penectomy is needed. Elective or therapeutic lymph-node dissection is recommended for inguinal metastatic disease, and depending on the disease status, unilateral or bilateral inguinal or ilioinguinal lymphadenectomy might be needed. The role of chemotherapy, as adjuvant or primary treatment in metastatic disease, needs to be defined in prospective clinical trials, which can be done in developing countries.

Invasive Penile Carcinoma: A Review

BACKGROUND

Penile carcinoma is an invasive epithelial tumor that may arise from penile skin or mucosa.

OBJECTIVE

To review the pathogenesis and the clinical and histopathologic features of invasive penile carcinomas, with emphasis on current guidelines for their diagnosis and treatment.

METHODS

Information available from the authors' clinical experience, review articles, case reports, clinical trials, and in vitro research studies identified from a computerized literature search on MEDLINE database and from Meetings' Abstract Books, including those from non-English literature, was considered.

RESULTS

Penile cancer may develop de novo or in association with underlying factors. Conditions predisposing to the development of penile cancer are delineated. The diagnosis should be suspected by clinical findings and must be confirmed histologically. Imaging techniques may be useful for staging and planning therapy. Therapeutic options include excisional surgery, laser destruction, cryosurgery, radiotherapy, immunotherapy, and chemotherapy.

CONCLUSIONS

Although there are no current guidelines for the treatment of penile carcinoma, surgical ablation probably represents the best option, as conservative treatments still deserve cautious evaluation because of the relatively small number of treated patients and the lack of good-quality comparative data. Regarding indications for lymph nodal dissection in patients showing no inguinal node enlargement, sentinel node mapping with targeted lymph node dissection is recommended for those with deeply invasive, high-grade tumors, whereas a watchful waiting may be advised for those with superficially invasive, low-grade tumors.

Colour Doppler ultrasound of the penis

Because it is a superficial structure, the penis is ideally suited to ultrasound imaging. A number of disease processes, including Peyronie's disease, penile fractures and penile tumours, are clearly visualized with ultrasound. An assessment of priapism can also be made using spectral Doppler waveform technology. Furthermore, dynamic assessment of cavernosal arterial changes after pharmaco-stimulation allows diagnosis of arterial and venogenic causes for impotence. This pictorial review illustrates the range of diseases encountered with ultrasound of the penis.

Imaging of male urethra

The male urethral imaging and pathology is not widespread in the radiology literature because this part of the urinary tract is easily studied by urologists with clinical or endoscopic examinations. Ultrasonography and MR imaging are increasingly being used in association with voiding cystourethrography and retrograde urethrography. The posterior urethra is being studied with voiding cystourethrography or voiding sonography which allows the detection of bladder neck pathology, post-surgical stenosis, and neoplasms. The functional aspects of the bladder neck and posterior urethra can be monitored continuously in patients with neuromuscular dysfunction of the bladder. The anterior urethral anatomy and pathology is commonly explored by retrograde urethrography, but recently sonourethrography and MR imaging have been proposed, distending the lumen with simple saline solution instead of iodinated contrast media. They are being used to study the urethral mucosa and the periurethral spongy tissue which can be involved in the urethral pathologies such as strictures, diverticula, trauma, and tumors. Imaging has an important role to play in the study of the diseases of the male urethra since it can detect pathology not visible on urethroscopy. The new imaging techniques in this area, such as sonography and MR, can provide adjunct information that cannot be obtained with other modalities.

MR imaging of the penis

The signal intensity of the corpora cavernosa of the penis at magnetic resonance (MR) imaging may vary from that of the corpus spongiosum; this difference is dependent on the rate of blood flow within the cavernous spaces that constitute the corporal bodies. Also visible at MR imaging are the layers of fibrous tissue that envelop the corporal bodies, the deep arteries and veins, subcutaneous connective tissue, tunica dartos, epidermis, and urethra. While the iliac, pudendal, perineal, and common penile arteries can be evaluated with three-dimensional MR angiography, the smaller end arteries of the penis have not yet been reliably demonstrated. MR imaging may be used to detect and stage penile and urethral cancers, identify and characterize benign penile masses, evaluate arteriogenic impotence, identify penile fractures, evaluate penile prostheses, localize periurethral abscesses, and identify plaques of Peyronie disease. With its direct multiplanar imaging capabilities, superb soft-tissue contrast, and excellent spatial resolution, high-field surface coil MR imaging can show the soft-tissue and vascular anatomy of the penis, as well as the appearance of many penile diseases.

Early experience in intermediate-risk penile cancer with sentinel node identification using the gamma probe

OBJECTIVES

To report the initial experience with sentinel node identification using the gamma probe in patients with intermediate-risk penile cancer (T2NXM0, or T1 with intermediate or high-grade disease) and impalpable groin nodes.

METHODS

Technetium-99m-labeled sulfur colloid was injected at the site of primary penile carcinoma 1 hour before surgery. The sentinel lymph nodes were located using the gamma probe and excised through a 3-cm inguinal incision. A full groin dissection was performed only in cases in which frozen section of the node demonstrated metastasis.

RESULTS

Nine sentinel nodes were identified by the gamma probe and excised in 5 men. In 3 patients, the sentinel nodes were negative bilaterally. In 2 patients, the sentinel node, although grossly normal, showed a single focus of metastasis by frozen section analysis. In both of these patients, a full groin dissection was carried out and revealed no other nodal metastases. All 5 remained free of recurrence (median follow-up 18 months, range 16 to 23).

CONCLUSIONS

In patients with microscopic involvement of a single lymph node only (confirmed by full groin dissection), gamma probe identification was 100% accurate. None of the patients with negative sentinel nodes had a recurrence. Biopsy of the sentinel nodes using the gamma probe can predict the presence or absence of inguinal node metastasis in patients with intermediate-risk penile cancer, sparing many patients the long-term morbidity of a full groin dissection. These initial results suggest further study is warranted.

Iridium-192 implantation for node-negative carcinoma of the penis: the Cookridge Hospital experience

Carcinoma of the penis is a rare tumour of the male urogenital tract, which may be treated by using several modalities. We present a single-centre experience of iridium-192 implantation. From 1980 to 1997, 31 patients with node-negative penile cancer were treated with an iridium-192 implant to the penis. A retrospective analysis of the case notes was made. Survival curves were estimated by the Kaplan-Meier method. The median age at treatment was 61.5 years. Twenty-seven patients presented with Jackson Stage I disease and four with Stage II disease. They were treated with an iridium-192 implant to the penis after biopsy (n = 25) or tumour excision (n = 6), with a 'watch and wait' policy for inguinal nodes. Four patients did not complete their implantation treatment and had additional external beam radiotherapy. The median follow-up was 61.5 months. The primary tumour was controlled in 25 of 31 patients (80.6%) by the implant. In all but one patient with primary relapse, surgical salvage was successful, although one patient died of septicaemia 3 weeks after surgery. Nodes were the initial site of relapse in seven patients, with associated relapse in the primary in one. The actuarial 5-year survival rates were as follows: overall survival 69.0 %, disease-specific survival (corrected for intercurrent deaths) 85.4%, relapse-free survival 57.8% and local relapse-free survival 75.6%. One patient underwent amputation for necrosis and 11 of 25 patients (44%) who achieved penile conservation required dilatation for urethral stenosis. In conclusion, iridium-192 implantation is a successful method of treatment for penile cancer in terms of local control, with preservation of function in the majority of patients. In those who do relapse at the primary site, surgical salvage is usually possible.

Predicting regional lymph node metastasis in carcinoma of the penis: a comparison between fine-needle aspiration cytology, sentinel lymph node biopsy and medial inguinal lymph node biopsy

OBJECTIVE

To evaluate the accuracy of clinical examination and fine-needle aspiration cytology (FNAC) in detecting groin metastases in patients with carcinoma of the penis, and to assess the positive and negative predictive value (PPV, NPV) of a preliminary sentinel lymph-node biopsy (SNB) and biopsy of the most medial of the horizontal group of inguinal lymph nodes (MIN) in selecting patients for an ilio-inguinal block dissection.

PATIENTS AND METHODS

The study comprised 28 patients (56 groins) with Stage I (one), Stage II (11) and Stage III (16) carcinoma of the penis. All patients underwent a detailed clinical examination followed by FNAC of the palpable inguinal nodes, and were subsequently submitted for block dissection. The MIN, the SN and the rest of the inguinal and iliac nodes were histologically examined separately for metastases.

RESULTS

The clinical evaluation had a sensitivity of 74%, a specificity of 61%, a PPV of 57% and a NPV of 77%. The corresponding values for FNAC were all 100%, and the specificity and PPV for both MIN and SN were 100%. The sensitivity and NPV of MIN were higher than for SN, although not significantly so.

CONCLUSION

Clinical examination alone is inaccurate in selecting patients with carcinoma of the penis for block dissection. FNAC is accurate and specific when nodes are palpable; in those with impalpable nodes a preliminary MIN biopsy followed by SNB if the MIN biopsy is negative will accurately select all patients with metastases in the groin nodes. This can be performed by examining frozen sections of the lymph nodes; if positive, block dissection can be carried out at the same time.

Squamous cell carcinoma of the penis: multivariate analysis of prognostic factors and natural history in monocentric study with a conservative policy

BACKGROUND

Penile carcinoma is uncommon in Western countries. Here we report on a large series of patients with squamous cell carcinoma (SCC) of the penis, describing prognostic factors, survival and therapeutic results.

PATIENTS AND METHODS

From 1973 to 1993, 102 patients with invasive SCC of the penis were treated at the Institut Gustave-Roussy. Precancerous lesions and conditions associated with penis cancer were analyzed retrospectively. Survival curves were estimated by the Kaplan-Meier method, and groups were compared for outcome by the log rank test for univariate comparisons and by Cox's proportional hazards model for multivariate analysis.

RESULTS

The median age at onset was 58 years. Sixty-nine patients presented with Jackson's stage I disease, 17 with stage II and 15 with stage III. The interval between the manifestation of symptoms and the diagnosis was more than a year in 13.7% of cases. Precancerous lesions were found in 17 (16.6%) patients, and a history of phimosis was noted in 25 (24.5%). In situ and invasive carcinoma were observed together in 17 (16.6%) cases and dysplasia was associated with invasive carcinoma in eight (7.8%) further cases. Conservative treatment was administered whenever feasible. Interstitial brachytherapy was performed alone or associated with limited surgery (local excision or circumcision) in 72 (70.6%) patients. Of the 28 patients with a local relapse, nine have died of their neoplasms (32%) compared to 21 of 28 patients with lymph node relapse (75%). The median follow-up was 111 months. Disease-free survival, disease-specific survival and overall survival were, respectively, 56%, 72% and 63% at five years and 42%, 66% and 50% at 10 years. Age (P = 0.01), the N status (P < 0.00001) or palpable nodes (P < 0.0038), corpus involvement (P = 0.006) and a verrucous histology (P = 0.038) had significant prognostic relevance for survival in the univariate analysis whereas the performance status, T status and Broders' grade did not. In the multivariate analysis only two parameters, involvement of the corpus (P < 0.0001) and palpable nodes (P = 0.009), were singled out as being independent variables influencing survival. A subgroup of nine patients with verrucous histologies were distinguished by their freedom from node involvement. These patients had an excellent prognosis: all are alive and disease-free. Penile integrity was preserved during follow-up in 54 patients (52.9%), 31 of whom are still alive. Of 72 patients treated by a conservative approach including brachytherapy, long-term penile integrity was maintained in 49 (68%).

CONCLUSION

Corpus involvement and clinically palpable nodes are highly statistically significant independent factors influencing overall survival. Node relapses remain a major cause of death. Thus, better management of lymph nodes is essential for improving survival even when conservative therapy is used to treat the primary.

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.

Magnetic resonance imaging in patients with penile carcinoma

The aim of the study was to determine the role of pre-operative magnetic resonance imaging (MRI), with and without contrast enhancement, in patients with penile carcinoma. Nine patients with a penile cancer were studied. The staging of the tumours was performed by clinical examination, MRI and surgery, according to the TNM classification. Six patients had primary tumours, of clinical stage T1 (n = 1) and T2 (n = 5). Three other patients had been previously treated and presented with a local recurrence of clinical stage T2. Surface-coil MRI was performed at 0.5 T with T1 weighted sequences before and after gadolinium-DOTA, and T2 weighted sequences. MRI results were compared with the clinical and surgical findings. T1 weighted sequences did not clearly demonstrate the margins of the tumours. T2 weighted sequences were the more useful in five patients, whereas contrast enhanced T1 weighted sequences allowed better delineation of the lesions in only three patients. Therefore, an imaging protocol should include spin echo T2 weighted sequences. Clinical examination correctly staged six of nine tumours; MRI, seven of nine tumours and the combination of both examinations, eight of nine tumours. MRI provided good evaluation of tumoral invasion into the penile shaft.

Laparoscopic lymphadenectomy in genitourinary malignancies

Laparoscopic pelvic lymphadenectomy has been applied to stage prostate cancer since 1989. These same laparoscopic techniques are being used to stage other urological malignancies. This report will detail the role of laparoscopic lymphadenectomy in staging genitourinary malignancies.