National patterns of care for early-stage penile cancers in the United States: How is radiation and brachytherapy utilized?

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.

Radiotherapy Versus Partial Penectomy for T1 Squamous Cell Carcinoma of the Penis

BACKGROUND

Radiotherapy (RT) represents an alternative treatment option for patients with T1 squamous cell carcinoma of the penis (SCCP), with proven feasibility and tolerability. However, it has never been directly compared with partial penectomy (PP) using cancer-specific mortality (CSM) as an end point.

METHODS

In the Surveillance, Epidemiology, and End Results database (2000-2020), T1N0M0 SCCP patients treated with RT or PP were identified. This study relied on 1:4 propensity score-matching (PSM) for age at diagnosis, tumor stage, and tumor grade. Subsequently, cumulative incidence plots as well as multivariable competing risks regression (CRR) models addressed CSM. Additionally, the study accounted for the confounding effect of other-cause mortality (OCM).

RESULTS

Of 895 patients with T1N0M0 SCCP, 55 (6.1%) underwent RT and 840 (93.9%) underwent PP. The RT and PP patients had a similar age distribution (median age, 70 vs 70 years) and more frequently harbored grade I or II tumors (67.3% vs 75.8%) as well as T1a-stage disease (67.3% vs 74.3%). After 1:4 PSM, 55 (100%) of the 55 RT patients versus 220 (26.2%) of the 840 PP patients were included in the study. The 10-year CSM derived from the cumulative incidence plots was 25.4% for RT and 14.4% for PP. In the multivariable CRR models, RT independently predicted a higher CSM than PP (hazard ratio, 1.99; 95% confidence interval, 1.05-3.80; p = 0.04).

CONCLUSION

For the T1N0M0 SCCP patients treated in the community, RT was associated with nearly a twofold higher CSM than PP. Ideally, a validation study based on tertiary care institution data should be conducted to test whether this CSM disadvantage is operational only in the community or not.

A Clinical Nomogram for Predicting Overall Survival in Patients With T1/T2 Penile Squamous Cell Carcinoma

BACKGROUND

To evaluate the overall survival (OS) and construct a nomogram to predict the OS of patients with penile squamous cell carcinoma (PSCC).

METHODS

This retrospective study analyzed data of patients with PSCC from the First Affiliated Hospital of Soochow University between 2012 and 2022. R software was used to explore factors influencing OS in PSCC. Kaplan-Meier method and log-rank test were employed for OS estimation. Univariate and multivariate Cox proportional hazards regression analyses were performed to identify these factors. A nomogram was created to identify the independent prognostic factors. The model was evaluated by concordance index, receiver operating characteristic (ROC) curves, and calibration plots.

RESULTS

A total of 159 patients with T1/T2 PSCC were included in the analysis. Patients with T2/N2 stage, older age, larger tumor size, high preoperative systemic immune-inflammation index (SII), and poor preoperative nutrition had a higher incidence of poor OS. Age, T/N stage, tumor size, and SII were identified as independent prognostic indicators. A prognostic nomogram was formulated, and its predictive accuracy for estimating OS in PSCC patients was validated through ROC curves and calibration plots.

CONCLUSION

The nomograms, based on age, T/N stage, tumor size, and high preoperative SII, provide a valuable tool for predicting 1-, 2-, and 3-year OS in patients with T1/T2 PSCC without distant metastases.

The Predictive Significance of Prognostic Nutritional Index and Serum Albumin/Globulin Ratio on the Overall Survival of Penile Cancer Patients Undergoing Penectomy

Objective: To assess the value of using the prognostic nutritional index (PNI) and serum albumin/globulin ratio (AGR) in predicting the overall survival (OS) of patients with penile cancer (PC) undergoing penectomy. Materials and methods: A retrospective analysis of 123 patients who were admitted to our hospital due to PC from April 2010 to September 2021 and who underwent penectomy were included in the study. The optimal cut-off value of the PNI and AGR was determined by receiver operating characteristic curve analysis. Kaplan-Meier analysis and the Cox proportional hazard model were used to evaluate the correlation between the PNI, AGR, and OS in patients with PC. Results: A total of 16 of the 123 patients died during the follow-up period, and the median follow-up time was 58.0 months. The best cut-off values of the PNI and AGR were set to 49.03 (95% confidence interval 0.705-0.888, Youden index = 0.517, sensitivity = 57.9%, specificity = 93.7%, p < 0.001) and 1.28 (95% confidence interval 0.610-0.860, Youden index = 0.404, sensitivity = 84.1%, specificity = 56.2%, p = 0.003). The Kaplan-Meier analysis showed that the OS of the patients in the high PNI group and the high AGR group was significantly higher than that of the patients in the low PNI group and the low AGR group (p < 0.001). The univariable analysis showed that the aCCI, the clinical N stage, the pathological stage, and the PNI, AGR, SII, and PLR are all predictors of OS in patients with PC (p < 0.05). The multivariable analysis showed that the PNI (risk rate [HR] = 0.091; 95% CI: 0.010-0.853; p = 0.036) and the AGR (risk rate [HR] = 0.171; 95% CI: 0.043-0.680; p = 0.012) are independent prognostic factors for predicting OS in patients with PC undergoing penectomy. Conclusions: Both the PNI score and the serum AGR are independent prognostic factors for predicting OS in patients with PC undergoing penectomy.

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.

miRNA and mRNA Expression Profiles Associated with Lymph Node Metastasis and Prognosis in Penile Carcinoma

Penile cancer (PeC) is a rare disease, and no prognostic biomarkers have been adopted in clinical practice yet. The objective of the present study was to identify differentially expressed miRNAs (DEmiRs) and genes (DEGs) as potential biomarkers for lymph node metastasis and other prognostic factors in PeC. Tumor samples were prospectively obtained from 24 patients with squamous cell carcinoma of the penis. miRNA microarray analysis was performed comparing tumors from patients with inguinal lymph node metastatic and localized disease, and the results were validated by qRT-PCR. Eighty-three gene expression levels were also compared between groups through qRT-PCR. Moreover, DEmiRs and DEGs expression levels were correlated with clinicopathological variables, cancer-specific (CSS), and overall survival (OS). TAC software, TM4 MeV 4.9 software, SPSS v.25.0, and R software v.4.0.2 were used for statistical analyses. We identified 21 DEmiRs in microarray analysis, and seven were selected for validation. miR-744-5p and miR-421 were overexpressed in tissue samples of metastatic patients, and high expression of miR-421 was also associated with lower OS. We found seven DEGs (CCND1, EGFR, ENTPD5, HOXA10, IGF1R, MYC, and SNAI2) related to metastatic disease. A significant association was found between increased MMP1 expression and tumor size, grade, pathological T stage, and perineural invasion. Other genes were also associated with clinicopathological variables, CSS and OS. Finally, we found changes in mRNA–miRNA regulation that contribute to understanding the mechanisms involved in tumor progression. Therefore, we identified miRNA and mRNA expression profiles as potential biomarkers associated with lymph node metastasis and prognosis in PeC, in addition to disruption in mRNA–miRNA regulation during disease progression.

Disruption of miRNA-mRNA Networks Defines Novel Molecular Signatures for Penile Carcinogenesis

Penile cancer (PeC) carcinogenesis is not fully understood, and no biomarkers are reported in clinical practice. We aimed to investigate molecular signatures based on miRNA and mRNA and perform an integrative analysis to identify molecular drivers and pathways for PeC development. Affymetrix miRNA microarray was used to identify differentially expressed miRNAs (DEmiRs) comparing 11 tumoral tissues (TT) paired with non-neoplastic tissues (NNT) with further validation in an independent cohort (n = 13). We also investigated the mRNA expression of 83 genes in the total sample. Experimentally validated targets of DEmiRs, miRNA-mRNA networks, and enriched pathways were evaluated in silico. Eight out of 69 DEmiRs identified by microarray analysis were validated by qRT-PCR (miR-145-5p, miR-432-5p, miR-487b-3p, miR-30a-5p, miR-200a-5p, miR-224-5p, miR-31-3p and miR-31-5p). Furthermore, 37 differentially expressed genes (DEGs) were identified when comparing TT and NNT. We identified four downregulated DEmiRs (miR-30a-5p, miR-432-5p, miR-487b-3p, and miR-145-5p) and six upregulated DEGs (IL1A, MCM2, MMP1, MMP12, SFN and VEGFA) as potential biomarkers in PeC by their capacity of discriminating TT and NNT with accuracy. The integration analysis showed eight dysregulated miRNA-mRNA pairs in penile carcinogenesis. Taken together, our findings contribute to a better understanding of the regulatory roles of miRNAs and altered transcripts levels in penile carcinogenesis.

Stereotactic Ablative Brachytherapy: Recent Advances in Optimization of Radiobiological Cancer Therapy

Brachytherapy (BT), a type of focal anti-cancer radiotherapy, delivers a highly focused radiation dose to localized tumors, sparing surrounding normal tissues. Recent technological advances have helped to increase the accuracy of BT and, thus, improve BT-based cancer treatment. Stereotactic ablative brachytherapy (SABT) was designed to improve the ablative effect of radiation, which was achieved via improved image guidance, and calculation of ablative dose, shorter treatment duration, and better organ preservation. Recently collected data characterized SABT as having the potential to cure various early-stage cancers. The method provides higher tumor control rate levels that were previously achievable only by surgical resection. Notably, SABT is suitable for application with unresectable malignancies. However, the pathological assessment of SABT irradiated tumors is limited due to difficulties in specimen acquisition. Prostate, lung, liver, and gynecological cancers are the most commonly reported SABT-treated malignancies. This study will give an overview of SABT, focusing on the advances in SABT optimization, and provide insights on the future benefits of the combined application of SABT with cancer immunotherapies.

Penile Sparing Techniques For Penile Cancer

Penile cancers are rare malignancies. Traditional surgical options, including partial and total penectomy, can dramatically affect a patient's quality of life and mental health. In select patients, penile sparing techniques (PST) have the potential to remove the primary tumor with comparable oncologic outcomes while maintaining penile length, sexual function, and urinary function. In this review, we aim to discuss the indications, advantages, and outcomes of the various PST currently available for men seeking an organ-preserving option for their penile cancer.

Characteristics of penile cancer in Japan: An analysis of nationwide hospital-based cancer registry data

OBJECTIVES

To investigate the clinical characteristics of patients with penile cancer in Japan using the nationwide hospital-based cancer registry database.

METHODS

Using hospital-based cancer registry data, we described the distribution of age, pathology, tumor-node-metastases classification, and first-course treatment in patients treated between 2012 and 2015. We compared the patterns of first-line treatment between elderly and non-elderly patients.

RESULTS

A total of 1012 patients were diagnosed with squamous cell carcinoma among 1773 patients with penile tumors who registered under topography code C60. The median age at diagnosis was 74 years, and 85.9% of patients were aged >60 years. The most common pathology was usual-type squamous cell carcinoma (91.9%), followed by verrucous carcinoma (5.0%), sarcomatoid carcinoma (1.1%), papillary carcinoma (0.7%), basaloid carcinoma (0.6%), adenosquamous carcinoma (0.4%), warty carcinoma (0.2%) and mixed carcinoma (0.1%). A total of 61.3% of patients were diagnosed with localized disease. In contrast, the proportions of patients with lymph node and distant metastases were 27.5% and 2.1% at diagnosis, respectively. The proportion of patients who were treated with chemotherapy as the first-course treatment was significantly lower among elderly patients (≥80 years) with clinical stage III (27.6% vs 7.1%, P = 0.0312) and clinical stage IV (53.2% vs 14.3%, P = 0.0086).

CONCLUSIONS

Most penile cancer patients in Japan are diagnosed with usual-type squamous cell carcinoma, and those with human papilloma virus-related squamous cell carcinomas are <1%. Chemotherapy for advanced penile cancer is administered less in Japanese elderly (≥80 years) patients.