Accuracy of MRI without intracavernosal prostaglandin E1 injection in staging, preoperative evaluation, and operative planning of penile cancer

Does MRI Have a Role in the Preoperative Staging of Penile Cancer?

Background Penile cancer is a rare malignancy usually requiring surgery to achieve oncological control of the primary tumour but often at the expense of functional length. The presenting stage of the primary is a crucial factor in determining the most appropriate surgical procedure. Accurate preoperative staging is essential, and current modalities include clinical and radiological assessment. Clinical staging can, however, be hampered by patient body habitus and unreliable for more advanced T4 tumours, whereas radiological staging allows for more detailed identification of tissue planes and tumour involvement. There is no clear consensus on the preferred imaging technique, although, in the current European Association of Urology penile cancer guidelines, MRI is recommended with the use of ultrasound when MRI is not available. It was recommended that having the penis in an erect state by the administration of intra-cavernosal prostaglandin gave a more detailed picture enabling a greater predictor of corporal involvement. Recent studies have, however, suggested that there may be no such advantage. Methodology A retrospective review was conducted of all patients who underwent surgery for penile cancer comparing the preoperative MRI stage with the final pathological stage between July 2009 and June 2023. In addition to the MRI, patients were given an intra-cavernosal injection of prostaglandin E1 to induce tumescence unless otherwise indicated. All imaging was reported by a single consultant uro-radiologist with surgery undertaken by a single surgeon and pathology reviewed through the supra-regional penile multidisciplinary team. Results A total of 136 penile cancer patients were included in the review. Within this cohort, 98 patients had an MRI without intra-cavernosal prostaglandin and the number who had Ta, T1, T2, T3 and T4 histopathological stages was 3, 31, 45, 18, and 1, respectively. The preoperative MRI stage had a low agreement with the final histological stage for early tumours, with sensitivities and specificity of 35% and 97% for T1 and 56% and 80% for T2, respectively. Sensitivity and specificity increased for cavernosal involvement at 83% and 95%, respectively. In addition, a further 38 patients had an MRI in conjunction with an injection of prostaglandin E1 which failed to show any diagnostic improvement in sensitivity or specificity in the preoperative MRI stage. Conclusions The use of MRI as a preoperative modality for staging penile cancer performs best for identifying tumour involvement of the cavernosal bodies. Performing the MRI with the penis erect with the use of an intra-cavernosal injection did not offer any additional benefit in accurately staging penile cancer.

Multiparametric Magnetic Resonance Imaging of Penile Cancer: A Pictorial Review

The role of multiparametric magnetic resonance imaging (mpMRI) in assessing penile cancer is not well defined. However, this modality may be successfully applied for preoperative staging and patient selection; postoperative local and regional surveillance; and assessments of treatment response after oncological therapies. Previous studies have been mostly limited to a few small series evaluating the accuracy of MRI for the preoperative staging of penile cancer. This review discusses the principles of non-erectile mpMRI, including functional techniques and their applications in evaluating the male genital region, along with clinical protocols and technical considerations. The latest clinical classifications and guidelines are reviewed, focusing on imaging recommendations and discussing potential gaps and disadvantages. The development of functional MRI techniques and the extraction of quantitative parameters from these sequences enables the noninvasive assessment of phenotypic and genotypic tumor characteristics. The applications of advanced techniques in penile MRI are yet to be defined. There is a need for prospective trials and feasible multicenter trials due to the rarity of the disease, highlighting the importance of minimum technical requirements for MRI protocols, particularly image resolution, and finally determining the role of mpMRI in the assessment of penile cancer.

Multi-parametric MRI without artificial erection for preoperative assessment of primary penile carcinoma: A pilot study on the correlation between imaging and histopathological findings

Purpose

We aimed to evaluate the diagnostic potential of non-erectile multi-parametric magnetic resonance imaging (mpMRI) for preoperative assessment of primary penile squamous cell carcinoma (SCC).

Method

Twenty-five patients who underwent surgery for penile SCC were included. Preoperative mpMRI without artificial erection was performed in all patients. The preoperative MRI protocol consisted of high-resolution morphological and functional sequences (diffusion-weighted imaging and dynamic contrast-enhanced MRI perfusion) covering the penis and lower pelvis. T and N staging, according to the 8th edition of the Union for International Cancer Control TNM classification, as well as the largest diameter and thickness/infiltration depth of the primary lesions were determined in all patients. Imaging data were retrospectively collected and compared with the final histopathology reports.

Results

Very good agreement was observed between MRI and histopathology for the involvement of corpus spongiosum (p = 0.002) and good agreement was observed for the involvement of penile urethra and tunica albuginea/corpus cavernosum (p < 0.001 and p = 0.007, respectively). Good agreement was observed between MRI and histopathology for overall T staging and weaker, but still good agreement was observed for N staging (p < 0.001 and p = 0.002, respectively). A strong and significant correlation was observed between MRI and histopathology for the largest diameter and thickness/infiltration depth of the primary lesions (p < 0.001).

Conclusions

Good concordance was observed between MRI and histopathological findings. Our initial findings indicate that non-erectile mpMRI is useful in preoperative assessment of primary penile SCC.

French AFU Cancer Committee Guidelines - Update 2022-2024: penile cancer

OBJECTIVE

To update French oncology guidelines concerning penile cancer.

METHODS

Comprehensive Medline search between 2020 and 2022 upon diagnosis, treatment and follow-up of testicular germ cell cancer to update previous guidelines. Level of evidence was evaluated according to AGREE-II.

RESULTS

Epidermoid carcinoma is the most common penile cancer histology. Physical examination is mandatory to define local and inguinal nodal cancer stage. MRI with artificial erection can help to assess deep infiltration in cases of organsparing intention. Node negative patients (defined by palpation and imaging) will present micro nodal metastases in up to 25% of cases. Invasive lymph node assessment is thus advocated except for low risk patients. Sentinel node dynamic biopsy is the first line technique. Modified bilateral inguinal lymphadenectomy is an option with higher morbidity. 18-FDG-PET is recommended in patients with palpable nodes. Chest, abdominal and pelvis computerized tomography is an option. Fine needle aspiration (when positive) is an easy way to assess inguinal palpable node pathological involvement. Its results determine the type of lymphadenectomy to be performed (for diagnostic or curative purposes). Treatment is mostly surgical. Free margins status is essential, but it also has to be organ-sparing when possible. Brachytherapy and topic agents can cure in selected cases. Lymph node assessment should be synchronous to the removal of the tumour when possible. Limited inguinal lymph node involvement (pN1 stage) can be cured with the only lymphadenectomy. In case of larger lymph node stage, one should consider multidisciplinary treatment including chemotherapy and inclusion in a trial.

CONCLUSIONS

Penile cancer needs demanding surgery to be cured, surrounded by chemotherapy in node positive patients. Lymph nodes involvement is a major prognostic factor. Thus, inguinal node assessment cannot be neglected.

Diagnostic Accuracy of MRI in Local Staging (T Category) of Penile Cancer and the Value of Artificial Erection: A Systematic Review and Meta-Analysis

BACKGROUND. Treatment recommendations of penile cancers are determined primarily by the local extent of the primary tumor. Clinical palpation is used for local staging. OBJECTIVE. We reviewed diagnostic performance of MRI in local staging of penile cancer in three clinical scenarios (questions [Qs] 1 through 3, Q1-Q3) and one imaging scenario (Q4). Q1 asked whether MRI reliably distinguishes ≤ T1 from ≥ T2 disease. Q2 asked whether clinical staging reliably identifies ≤ T1 versus ≥ T2 disease and how clinical staging compares to MRI. Q3 asked if MRI is accurate for diagnosis of T3 disease. Q4 asked if artificial erection (by intracavernosal injection of prostaglandin E₁) improved accuracy of MRI in T categorization. EVIDENCE ACQUISITION. MEDLINE, EMBASE, and Cochrane Library databases were searched through September 13, 2021, for studies evaluating local staging of penile cancer using MRI with surgical pathology as the reference standard. Diagnostic accuracy was calculated using a bivariate random-effects model and hierarchic summary ROC mode Meta-regression was performed to test for covariate effects of MRI and artificial erection in Q3 and Q4, respectively. EVIDENCE SYNTHESIS. Eight studies and 481 patients were included. The sensitivity and specificity of MRI for Q1 were 86% (95% CI, 73-94%) and 89% (95% CI, 77-95%), respectively. AUC for MRI (0.94; 95% CI, 0.92-0.96) did not differ from clinical staging (0.87; 95% CI, 0.84-0.90; p = .83). For Q3, MRI had sensitivity and specificity of 80% (95% CI, 70-87%) and 96% (95% CI, 85-99%), respectively. For Q4, sensitivity and specificity for MRI with versus without artificial erection were 85% (95% CI, 71-92%) and 93% (95% CI, 77-98%) versus 86% (95% CI, 68-95%) and 84% (95% CI, 70-93%), respectively (p = .50). CONCLUSION. MRI staging of penile cancer may be considered for ≤ T1 versus ≥ T2 disease but did not appear more accurate than clinical staging. High specificity of MRI for diagnosis of ≥ T3 disease suggests that MRI may be useful when organ-sparing approaches are planned. MRI with and without artificial erection showed similar accuracy in local staging. CLINICAL IMPACT. MRI, with or without artificial erection, may be valuable in routine preoperative evaluation of local staging of penile cancer, particularly when organ-sparing options are considered.

Imaging for the Initial Staging and Post-Treatment Surveillance of Penile Squamous Cell Carcinoma

Although relatively rare in the United States, penile squamous cell carcinoma is encountered worldwide at a higher rate. Initial diagnosis is often made on clinical exam, as almost all of these lesions are externally visible and amenable to biopsy. In distinction to other types of malignancies, penile cancer relies heavily on clinical nodal staging of the inguinal lymph node chains. As with all cancers, imaging plays a role in the initial staging, restaging, and surveillance of these patients. The aim of this manuscript is to highlight the applications, advantages, and limitations of different imaging modalities in the evaluation of penile cancer, including ultrasound, computed tomography, magnetic resonance imaging, and positron emission tomography.