International Journal of Radiation Oncology*Biology*Physics
Clinical InvestigationStage Presentation, Care Patterns, and Treatment Outcomes for Squamous Cell Carcinoma of the Penis
Introduction
Penile cancer is rare in the United States, accounting for less than 1% of male malignancies. In 2013, the American Cancer Society estimated that there will be 1570 new cases and 310 deaths in the United States (1). Although uncommon in the United States and Europe, it is the leading cause of male cancer in Uganda and accounts for up to 10% of male malignancies in the Indian subcontinent, Africa, and Latin America (2).
The majority of penile cancers are epithelial, with squamous cell histology accounting for 95% of cases. Other histologies, including basal cell carcinoma, melanoma, sarcoma, and adenocarcinoma, are more rare (3). Risk factors associated with the development of squamous cell carcinoma include human papillomavirus (HPV) (4), phimosis, smoking, and human immunodeficiency virus (HIV), whereas circumcision may be protective 5, 6, 7. The primary tumor is usually located on the glans (48% of cases) or prepuce (21% of cases) and is found on the shaft in less than 2% of cases (8).
The conventional treatment for squamous cell carcinoma of the penis has been total or partial penectomy, which has achieved greater than 90% local control (9). However, concern for significant functional morbidity and psychosexual issues has led to the emergence of organ-sparing treatment options (10). Penile-conserving procedures include Mohs microscopic surgery, external beam radiation therapy (EBRT), interstitial brachytherapy, laser ablation, and cytotoxic chemotherapy (11). Although penile-conserving treatment options do not yield the same local control as radical surgical techniques, given the reduction in morbidity, there is general consensus that penile-conserving treatments are appropriate for low-grade, low-stage (Tis, Ta, T1) penile cancer.
Because of the low incidence of penile cancer, no randomized studies have been completed comparing penile-conserving treatment with total or partial penectomy. Data on penile cancer is mainly derived from single-center retrospective studies with small sample sizes. Using the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) Program registry, this study aims to evaluate TMN stage distribution at presentation, care patterns, and treatment outcomes for surgery and radiation therapy (RT) for squamous cell carcinoma of the penis.
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Methods and Materials
We used the SEER database to extract information on subjects diagnosed with squamous cell carcinoma of the penis between the years 1988 and 2006. All subjects were staged according to the American Joint Committee on Cancer (AJCC), sixth edition, TNM system based on the SEER Extent of Disease classification (years 1988-2002) or the SEER collaborative staging system (years 2003 onward). In the majority of cases, the Extent of Disease (EOD) and Collaborative Staging (CS) fields correlated exactly
Results
There were 2458 subjects identified. Table 1 shows the demographics and initial presentation for the 2427 subjects with known surgical and RT status. The mean age for all subjects was 66.8 years (range, 17-102 years). The median follow-up for survivors was 45 months. Penile cancer was most commonly found in subjects of white ethnicity, accounting for 2065 (85.1%) of the cases, but it also occurred in 228 (9.4%), 89 Asians/Pacific Islanders (3.6%), and 19 Native Americans (<1%). The
Discussion
Treatment modalities for penile cancer include total or partial penectomy, Mohs microscopic surgery, RT (either external beam or interstitial brachytherapy), laser ablation, and cytotoxic chemotherapy (11). Because of the psychosocial issues associated with penectomy, there has been a trend toward penile-preserving modalities when possible. According to the European Association of Urology (EAU), a penile-sparing modality should be used for Ta to T1, grade 1 to 2 tumors and can be considered in
Conclusion
In summary, squamous cell carcinoma of the penis is a rare male malignancy in the United States that often presents in the early stage with T1, N0, M0, grade 1, or grade 2 disease. The majority of patients identified in the SEER database were treated with surgery, and only a small fraction of patients were treated with RT, either alone or as adjuvant therapy with surgery. Lymph node sampling in fully staged subjects revealed pathologically positive lymph nodes in the majority of patients, thus
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Conflict of interest: none.