Management of penile cancer

Penile cancer is an uncommon tumor with a significantly higher incidence in some areas of underdeveloped countries. Unfortunately, delay on the part of the physician in initiating diagnosis may be considerable and many patients are referred to treatment after developing advanced disease. There is a large volume of data on penile cancer in Brazil. Losing patients to follow-up is common and in some areas of the country, penile cancer accounts for 17% of all malignancies in men. In these less developed areas, penile carcinoma represents one of the most important health problems. A recent epidemiological study sponsored by the Brazilian Society of Urology (SBU) gave us an idea about the complexity of the problem [1]. For example, the highest incidence rates of penile carcinoma were found in Maranhão and São Paulo. Maranhão is situated in an underdeveloped area and São Paulo is the richest state of the country. An explanation for this contradiction is the large migration of the poor from underdeveloped areas to São Paulo. The SBU and the federal government are now waging a campaign to increase early diagnosis and improve health measures in order to eradicate the disease in the future. Most tumors of the penis are of lower grades. Lack of correlation between grade and survival has been noted by a number of investigators. Other series report reduced survival among patients with anaplastic tumors. Several studies have also emphasized the association of high-grade disease with regional nodal metastases. At the Brazilian National Cancer Institute we adopt the 1978 TNM staging classification system for penile carcinoma. The problem with the current TNM version is the difficulty of assigning nodal status before definitive therapy. We favor the 1978 TNM version because we believe that clinical stage must be assigned before definitive therapy and that such a staging system has prognostic significance. Unfortunately, the 1978 TNM version did not provide a designation for pelvic nodal status, a known indicator of poor prognosis. Before the administration of therapy, a biopsy is required to provide histologic confirmation of the diagnosis of penile cancer and staging information by assessing the depth of microscopic invasion. Adjacent normal tissue should be included to evaluate invasion, a critical differential point with regard to planning definitive surgery. Primary treatment of penile cancer depends on the size and location of the tumor. Actually, surgery is the gold standard method used to treat penile carcinoma although radiation therapy has yielded local control rates similar to surgical resection. The scope of surgery varies from wide excision to total penectomy and emasculation. Circumcision is performed in selected patients whose lesions were limited to the foreskin. Successful local control by partial penectomy depends on division of the penis at least 2 cm proximal to the gross tumor extent, leaving tumor-free margins. Total penectomy is indicated in lesions whose size or location precludes adequate excision with a functional residual remnant by partial penectomy. Mohs micrographic surgery is used for the treatment of selected patients with small, superficial penile cancers. The Mohs technique involves excision of the penile lesion and microscopic examination of the underside of each layer for systematic inspection of serial sections. Laser ablation using a neodymium:yttrium-aluminum garnet (Nd:YAG) or carbon dioxide (CO2) laser have also been used in selected patients with small superficial or superficially invasive penile cancers. The risk of local recurrence after this penis-conserving therapy is significantly related to category T, with 10% local recurrences in stage T1 tumors in contrast to 32% and 100% in stages T2 and T3 tumors, respectively. Radiation therapy techniques include external-beam irradiation, iridium molds or wires, and interstitial brachytherapy. Using externalbeam radiation therapy, a control rate of 39–65% can be achieved. For T1–T2 penile carcinoma, an overall local control rate of 74–86% can be achieved with Ir interstitial implants and of 80% with brachytherapy. Metastases to the regional inguinal nodes are the earliest route of dissemination from penile carcinoma. Due to inflammatory factors, it is difficult to clinically detect metastatic involvement of these inguinal lymph nodes. Other potential reasons for false-negative examinations include obesity, preexisting edema, and changes from prior therapy (radiation, inguinal surgery). Dynamic sentinel node biopsy has been used for patients with node negative T2–T3 penile carcinoma. This procedure has also been used for staging the contralateral side in patients with clinically unilateral lymph node involvement. In general, subsequent contralateral inguinal node dissection and ipsilateral pelvic lymph node dissection was carried out if two or more inguinal lymph nodes were involved. However this technique has been associated with a false-negative rate of 16% [2]. The results of the use of isolated gamma probe for sentinel node penile carcinoma detection was recently published by GonzagaSilva et al. [3] from the Brazilian Federal University of Ceará. Over the last 5 years at their cancer hospital, 3 new cases of penile carcinoma have been identified per month and 27 newly diagnosed patients (T1, T2, N0) were included in a prospective study. The authors found that the isolated gamma probe technique has a very low sensibility and high false-negative rate concluded that this isolated technique is unreliable. Dr. Simon Horenblas, from the Netherlands Cancer Institute, a pioneer in this field, provided an editorial comment on this article. He believes to be able, with support of refinements, to bring down the false-negative rate of 22% to an acceptable 4.8%. Our group, at the Brazilian National Institute of Cancer is performing a