22 Penis cancer

Penis cancer

4

THE GEC ESTROHANDBOOKOF BRACHYTHERAPY | Part II Clinical Practice Version 1 - 15/07/2022

3

2

3

1

1

1

5 5

2

1

1

1

5 5

2

4

2

4

Figure 1: MRI of the penis, axial and sagital view (T2 weighted. 1. Corpora cavernosa 2. Ventral corpus spongiosum 3. Glans penis

4. Bulbous spongiosum 5. Cavernosal arteries

Of the various SCC subtypes, verrucous has the best prognosis, despite the fact that only 25% are reported to be associated with HPV. The basaloid type is most frequently associated with HPV positivity, reported in up to 2/3 of cases, while the classic SCC (not-otherwise-specified (NOS)), sarcomatoid and adenosquamous are HPV positive less often[8]. The most common HPV type is HPV 16[8]. HPV DNA is highly prevalent in penile dysplasia and penile intraepithelial neoplasia (PeIN) [9]. P16 status can be evaluated by immunohistochemistry (IHC) and is considered representative of HPV infection [10]. There is an association with better disease specific survival for those positive for HPV by either PCR (polymerase chain reaction) or IHC [11]. Similar to vulvar cancer, there are 2 epidemiologic pathways for SCC of the penis, an HPV-related pathway and the traditional chronic inflammation pathway seen more frequently in older individuals and in association with conditions such as lichen sclerosis. Recent work has demonstrated the potential for biologic therapy aimed at mutations like PDL1. PDL1 is more prevalent in locally advanced (> 4 cm diameter) and node positive cases (69% PDL1 positive). PDL1 positivity has been reported to be 100% in high grade cancers [12]. A Swedish series reported 31%PDL1 positivity in 222 patients and found it associated with reduced cause specific survival (CSS)[13].

urethral infiltration, or extension to cutaneous structures. Palpation of the groins should also look for regional node involvement. As depth of infiltration can be difficult to assess clinically, clinical examination is completed with a radiological assessment that should include magnetic resonance imaging (MRI) withmedically- induced erection. PGE1 alprostadil injection accentuates the boundary between the tunica albuginea and the corpus cavernosa on T2 weighted images, which is important in local staging. In addition, MRI can assess the degree of infiltration of the corpus spongiosum. Historically, patients with clinical infiltration of the corpora cavernosa would not be offered brachytherapy [14] but it is uncertain whether early subclinical infiltration detected on MRI should also exclude brachytherapy as an option. In the case of contra-indications to MRI, an ultrasound performed by an expert radiologist may be useful to assess tumour infiltration. In addition to local staging, MRI provides adequate cross-sectional imaging to assess for potential inguinal or pelvic lymph node involvement, which is the main prognostic factor. For patients with disease confined to the penile glans by clinical and radiological assessment, more invasive lymph node staging may be indicated according to the grade and depth of infiltration of the primary tumour. Patients with Ta-T1 grade 1 tumours on biopsy have a low risk of occult lymph node involvement and therefore surveillance of the groins is usually recommended. Patients with pT1 Grade2 tumours are considered intermediate risk, while pT1G3 and pT2-3 Grade 1-3 tumours are at high risk of lymph node metastases. In patients with intermediate to high- risk tumours, a bilateral inguinal sentinel lymph node sampling is associated with less lymphedema than bilateral modified inguinal lymph node dissection. In experienced centres, sentinel lymph node sampling is therefore recommended to complete lymph node staging with minimal morbidity. For patients with clinical or radiological inguinal involvement, a fine needle aspiration should be performed to confirm pathology, followed by radical inguinal dissection on the involved side. The contralateral side may be managed with a modified inguinal lymph node dissection.

5. WORK UP

Primary workup should look for any potential contra-indications to brachytherapy. Clinical examination of the penis is important to determine suitability for brachytherapy as well as to decide the most suitable geometry for the implant. It should report the tumour topography, the size (dimensions) of the tumour, whether it is ulcerated or infiltrating, the presence of multifocal disease,