Contemporary role of radiotherapy in the management of penile cancer

Brachytherapy and external beam radiation in the management of primary penile cancer - Game changer for organ preservation?

OBJECTIVE

In squamous cell carcinoma of the penis (PeCa), treatment options for primary tumors vary by disease stage and may include surgery, radiation, topical chemotherapy, or laser excision. This review aims to highlight the current evidence on the value of radiotherapy as an organ-preserving strategy in primary PeCa.

MATERIAL AND METHODS

Manuscripts on primary PeCa treatment with external beam radiotherapy (EBRT) and brachytherapy were evaluated via Scopus, PubMed/MEDLINE, and Web of ScienceTM (2013-2023) to assess their efficacy and safety. Animal studies, studies with <5 patients, and case reports were excluded.

RESULTS

Radiotherapy offers the potential for organ preservation with tumor control rates comparable to radical surgery, while disease-specific survival rates up to 70 % were experienced with EBRT. Brachytherapy (BT) is the preferred method of irradiation for glans-limited tumors, whereas a higher relapse risk is expected for tumors >4 cm. BT shows 73 % amputation-free survival at 8-10 years and 81 % progression-free survival at 5-10 years. Compared with BT, total amputation significantly improves 5-year disease-free survival rate. BT offers a superior 5-year local control and penile preservation rates compared to EBRT. Common acute toxicities of brachytherapy include radiodermatitis, sterile urethritis, and urethral adhesions. The primary late adverse events of BT are soft tissue necrosis (0-31 %) and meatal stenosis (0-43 %).

CONCLUSION

BT is a favorable radiation modality, offering an efficient and conservative approach. HDR BT is favored for its enhanced dose distribution and radiation protection. Collaboration between radiation oncologists and urologists is essential in order to provide an optimal patient selection and manage toxicities thus optimizing patient outcomes.

A Technique to Deliver Conformal External Beam Radiation for Squamous Carcinoma of the Penile Glans and Urethra

This study presents an approach to external beam radiation therapy for treating penile cancer using a small water bath. This modified technique involves the use of an acrylic, cuboid-shaped water bath with dimensions 6 × 6 × 8 cm3. The water bath is filled with readily available saline solution maintained at room temperature. The patient is positioned in the prone position, and the penis is placed within the water bath. The isocenter is set at the center of the water bath, and bilateral beams are positioned at 89.1° and 270.9°. The proposed technique was evaluated based on dose calculations, demonstrating a clinical target volume dose with a Dmax of 103.5% and a Dmin of 100.0% of the prescribed dose. Additionally, the method showed a low organs-at-risk dose, with a Dmean of only 1% for the testicles. The treatment zone inside the water bath also showed a uniform dose distribution. This technique not only offers high treatment efficiency and more accurate dose distribution to the targeted area but also provides additional benefits, including reduced toxicity to organs at risk and increased device utilization efficiency. In conclusion, the proposed modified external beam radiation therapy method presents a promising alternative for patients with penile cancer, enhancing treatment precision and safety.

High-Dose-Rate Brachytherapy as an Organ-Sparing Treatment for Early Penile Cancer

BACKGROUND

Low-dose-rate brachytherapy is an effective organ-sparing treatment for patients with early-stage penile cancer. However, only limited data are available on the role of high-dose-rate brachytherapy (HDR-BT) in this clinical setting.

METHODS

Between 2002 and 2020, 31 patients with early penile cancer were treated at our center with interstitial HDR BT at a dose of 18 × 3 Gy twice daily. A breast brachytherapy template was used for the fixation of stainless hollow needles.

RESULTS

The median follow-up was 117.5 months (range, 5-210). Eight patients (25.8%) developed a recurrence; of these, seven were salvaged by partial amputation. Six patients died of internal comorbidities or a second cancer. The probability of local control at 5 and 10 years was 80.7% (95% CI: 63.7-97.7%) and 68.3% (95% CI: 44.0-92.6%), respectively. Cause-specific survival was 100%. Only one case of radiation-induced necrosis was observed. The probability of penile sparing at 5 and 10 years was 80.6% (95% CI: 63.45-97.7%) and 62.1% (95% CI: 34.8-89.4%), respectively.

CONCLUSIONS

These results show that HDR-BT for penile cancer can achieve results comparable to LDR-BT with organ sparing. Despite the relatively large patient cohort-the second largest reported to date in this clinical setting-prospective data from larger samples are needed to confirm the role of HDR-BT in penile cancer.

Updates in the use of radiotherapy in the management of primary and locally-advanced penile cancer

Objective

Penile cancer is a rare malignancy in most developed countries, but may represent a significant oncologic challenge in certain African, Asian, and South American regions. Various treatment approaches have been described in penile cancer, including radiotherapy. This review aimed to provide a synopsis of radiotherapy use in penile cancer management and the associated toxicities. In addition, we aimed to discuss palliative radiation for metastases to the penis and provide a brief overview of how tumor biology may assist with treatment decision-making.

Methods

Peer-reviewed manuscripts related to the treatment of penile cancer with radiotherapy were evaluated by a PubMed search (1960–2021) in order to assess its role in the definitive and adjuvant settings. Selected manuscripts were also evaluated for descriptions of radiation-related toxicity.

Results

Though surgical resection of the primary is an excellent option for tumor control, select patients may be treated with organ-sparing radiotherapy by either external beam radiation or brachytherapy. Data from randomized controlled trials comparing radiotherapy and surgery are lacking, and thus management is frequently determined by institutional practice patterns and available expertise. Similarly, this lack of clinical trial data leads to divergence in opinion regarding lymph node management. This is further complicated in that many cited studies evaluating lymph node radiotherapy used non-modern radiotherapy delivery techniques. Groin toxicity from either surgery or radiotherapy remains a challenging problem and further risk assessment is needed to guide intensification with multi-modal therapy. Intrinsic differences in tumor biology, based on human papillomavirus infection, may help aid future prognostic and predictive models in patient risk stratification or treatment approach.

Conclusion

Penile cancer is a rare disease with limited clinical trial data driving the majority of treatment decisions. As a result, the goal of management is to effectively treat the disease while balancing the importance of quality of life through integrated multidisciplinary discussions. More international collaborations and interrogations of penile cancer biology are needed to better understand this disease and improve patient outcomes.

Radiotherapy for penile cancers

Penile cancers are uncommon and should be treated in expert center. Radiotherapy indications are mainly limited to exclusive brachytherapy for early stage penile glans cancer. Brachytherapy yields to excellent outcome for disease control and organ and function preservation. Only scarce data are available for external beam radiation therapy. It could be considered as palliative setting for irradiation of the primary tumor. For lymph node irradiation, external beam radiation therapy (with or without chemotherapy) could be discussed either as neoadjuvant approach prior to surgery for massive inguinal lymph node invasion or as adjuvant approach in case of high-risk of relapse. However, these cases should be discussed on an individual basis, as the level of evidence is poor. We present the recommendations of the French Society of Oncological Radiotherapy on the indications and techniques for external beam radiotherapy and brachytherapy for penile glans cancer.

Recommendations and Clinical Validation of Inguinal Clinical Target Volume Delineation in Penile Cancer

PURPOSE

This study determined the patterns of distribution of inguinal nodes and the optimal margin needed around the femoral vessels to propose guidelines for inguinal clinical target volume (CTV) delineation in penile cancer.

METHODS AND MATERIALS

Patients with biopsy-proven penile squamous cell carcinoma with inguinal node metastases were identified on a computed tomography scan. Distribution of nodes and distance of nodes to the nearest femoral vessel and inferior edge of pubic symphysis (IPS) were obtained. A 3-dimensional CTV margin to cover 95% of the nodes was estimated to evolve contouring guidelines. A comprehensive contouring guide with a visual atlas for inguinal CTV delineation was created. The proposed CTV was prospectively validated in 14 consecutive patients with penile squamous cell carcinoma treated with post-operative radiation therapy to the inguino-femoral region.

RESULTS

Of the 222 inguinal lymph nodes analyzed in 33 patients, 99% were located anterior (81% antero-medial, 18% antero-lateral) to femoral vessels. A majority (95%) of the antero-laterally located nodes were superior to IPS. Margin around the femoral vessels to cover 95% of the nodes for supra-IPS region in anterior, medial, and lateral directions was 29, 23, and 21 mm, respectively, and for infra-IPS region in anterior and medial directions was 21 and 23 mm, respectively. Cranial and caudal extent of CTV delineation with respect to IPS was at 48 and 50 mm, respectively for 95% nodal coverage. On prospective validation, after a median follow-up of 24 months (range, 5-31), none of the patients developed marginal recurrences. Grade 1 and grade 2 lymphedema was seen in 6 (42.8%) and 4 (28.5%) patients, respectively.

CONCLUSIONS

This study analyzed pattern of distribution of inguinal nodes and proposes guidelines for inguinal CTV delineation in penile cancer. The proposed guidelines were validated prospectively in a small cohort of patients and found to be implementable and safe.

Penile cancer

Penile squamous cell carcinoma (PSCC) is a rare cancer with orphan disease designation and a prevalence of 0.1-1 per 100,000 men in high-income countries, but it constitutes up to 10% of malignancies in men in some African, Asian and South American regions. Risk factors for PSCC include the absence of childhood circumcision, phimosis, chronic inflammation, poor penile hygiene, smoking, immunosuppression and infection with human papillomavirus (HPV). Several different subtypes of HPV-related and non-HPV-related penile cancers have been described, which also have different prognostic profiles. Localized disease can be effectively managed by topical therapy, surgery or radiotherapy. As PSCC is characterized by early lymphatic spread and imaging is inadequate for the detection of micrometastatic disease, correct and upfront surgical staging of the inguinal lymph nodes is crucial in disease management. Advanced stages of disease require multimodal management. Optimal sequencing of treatments and patient selection are still being investigated. Cisplatin-based chemotherapy regimens are the mainstay of systemic therapy for advanced PSCC, but they have poor and non-durable responses and high rates of toxic effects, indicating a need for the development of more effective and less toxic therapeutic options. Localized and advanced penile cancers and their treatment have profound physical and psychosexual effects on the quality of life of patients and survivors by altering sexual and urinary function and causing lymphoedema.

Novel treatment setup for urethral carcinoma radiotherapy: A complete response case report

A homemade personalized penis holder can provide the reproducibility of the penis during urethra carcinoma (UC) radiotherapy.

Prognostic Factors for Penile Cancer and Survival in Response to Multimodality Therapy

Purpose

To report treatment outcomes of penile cancer in a single institution in Thailand and to identify prognostic factors for survival, highlighting the crucial role of multi-modality treatment (MMT).

Patients and Methods

Squamous cell carcinoma of penis patients who were treated at Srinagarind hospital between 2007–2015 were retrospectively analyzed. Clinical and pathological data were retrospectively reviewed. Overall survival (OS) was calculated using the Kaplan-Meier method and data were compared using the Log rank test. Cox regression analysis of factors affecting survival was conducted.

Results

A total of 70 patients were identified with a median follow-up of 69.4 months. Twenty-eight patients (40%) presented with early-stage (stage I or II), whereas 42 patients (60%) were stage III or IV disease. The median OS was 29.3 months (Interquartile range 10.5 months - not reached) for the entire cohort. Nodal involvement was the only factor identified from the multivariate model with the adjusted HR or 5.74 (95% CI 2.52–13.04). For patients with stage IIIB/IV, multi-modality treatment (MMT) resulted in longer survival when compared with surgery alone (HR 0.37; 95% CI 0.16–0.90).

Conclusion

Patients with penile cancer in Thailand presented with younger age and more locally advanced stage. Nodal involvement is the single poor prognostic factor for OS and MMT was associated with longer survival in stage IIIB/IV disease.

New insight in penile cancer

Penile cancer is a rare disease. Most of penile cancer are squamous cell carcinoma. Diagnosis is based on self-examination, clinical examination and confirmatory biopsy. Several imaging techniques could be used for staging purposes. However, the best modality for staging in intermediate and high-risk patients is by surgical evaluation and the use of inguinal lymph node dissection, that has also a therapeutic effect. Unfortunately, inguinal lymph node dissection is underused. Penile cancer treatment may have a major adverse impact on urinary and sexual function and on quality of life. Penile-sparing surgery and radiation therapies are available, and in selected patients offer good outcomes with acceptable rates of local recurrence. Penile-sparing surgery should be preferred when indicated. Follow-up with periodical controls is mandatory up to 5 years. However, risk of local, nodal and distant recurrence after 5 years was reported. Imaging is not routinely recommended during follow-up. Patients should be trained to self-examination during the follow-up.