Penile carcinoma: lessons learned from vulvar carcinoma

Abstract

Purpose: Penile carcinoma is rare in the developed world and treatment guidelines are often based on marginal clinical data. Prospective controlled studies are virtually absent and meta-analyses are rare. Vulvar carcinoma, on the other hand, has many parallels to penile carcinoma, and the level of evidence for diagnosis and treatment is more robust. Therefore, we assessed the body of literature on vulvar carcinoma to identify potential improvements in the care of patients with penile carcinoma.

Materials and methods: A literature review was performed on vulvar carcinoma and direct comparisons were made to a similar review of the literature on penile carcinoma.

Results: Several aspects of vulvar carcinoma management are clearly established and deserve closer evaluation in penile carcinoma. For example, human papillomavirus is identified in a high percentage of patients with vulvar carcinoma but is understudied in penile carcinoma. Further study is of potential clinical value, especially with the development of human papillomavirus vaccines for prevention. Penile carcinoma TNM staging does not adequately stratify survival or risk of advanced disease. Staging of vulvar carcinoma is dependent on tumor size and depth of invasion measured in millimeters, as opposed to the invasion of underlying structures in penile carcinoma. Management of the inguinal nodes is more refined for vulvar carcinoma, where lymphatic mapping has been conducted and sentinel node biopsy has proven to be highly effective in multicenter trials. Finally, the efficacy of adjuvant radiation and chemotherapy has been tested in controlled trials or reported in meta-analyses for vulvar carcinoma, which are both lacking for penile carcinoma. Radiation after inguinal node dissection, for example, has been shown to enhance survival in patients with defined risk factors. Neoadjuvant chemoradiation is recommended before surgery for advanced vulvar carcinoma.

Conclusions: Evidence derived from studies on vulvar carcinoma can be extrapolated to penile carcinoma to help guide clinical trials and future research directions to enhance the treatment of these patients.