Improving our understanding of male urethral cancer : An example of the strengths and limitations of the SEER cancer registry

✍ Scribed by Michael P. Porter

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 66 KB
• Volume: 117
• Category: Article
• ISSN: 0008-543X
• DOI: 10.1002/cncr.25783

✦ Synopsis

Urethral cancer is rare in the United States, with an estimated incidence among men of 4.3 cases per million personyears. 1 The most common histologic subtype is transitional cell carcinoma, followed by squamous and adenocarcinoma. Because of its rarity, the clinical characteristics, including best treatment strategies and expected outcomes, are not well understood. Case series from centers treating a large volume of urethral cancer patients can provide some insight; however, even the largest case series contain fewer than 50 patients. 2 Findings from case series are also not always generalizable to the average patient.

In this issue of Cancer, Rabbani 3 used Surveillance, Epidemiology, and End Results (SEER) data to describe the clinical characteristics and outcomes of male patients with urethral cancer. Among incident cases from1988-2008, 2065 men with incident urethral cancer, without a previous diagnosis of bladder cancer, were identified. Overall and disease-specific, 5-year survival rates were 46.2% and 68%, respectively. The most common histologic subtypes were transitional cell (77.6%), squamous cell (11.9%), and adenocarcinoma (5.0%). Nearly a quarter of patients presented with locally advanced tumors (T2-T4), and 22.1% had nodal involvement. Sixty-one percent of patients underwent simple surgical excision, 10.1% underwent radical resection, and 10.2% received some form of radiotherapy. Among the subset of 453 men with stage T2-T4 tumors, 98 underwent radical surgery alone, 97 underwent radiation alone, and 15 received both; 243 had neither radical surgery nor radiation. In multivariate survival analysis, predictors of poor outcome included advancing age, higher grade, higher local stage, visceral metastases, and nodal metastases. The authors also note that in the subgroup of patients with T2-T4 tumors, those who underwent radical surgical resection had improved cancer-specific survival compared with those who underwent radiation alone or to those who did not receive radical surgery or radiation.

Tumor registries, such as the SEER, provide valuable information that assist our understanding of cancer incidence and survival in the United States. 4 SEER is maintained by the National Cancer Institute and currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 26% of the US population. The large size of the population at risk makes this registry ideal for gathering data to study rare tumors, and its population-based ascertainment method allows observations of tumor characteristics and outcomes that can be generalized to ''average'' patients. SEER is the only national source of cancer incidence and survival data in the United States, and SEER data are considered by most to be accurate and reliable. A detailed description of the SEER program can be found at the SEER website. 4 Since its beginning in 1973, the SEER database has been used to answer hundreds of research questions. SEER data are well suited for some research questions and methodologies but not all.

Descriptive studies report observations without a specific hypothesis. Perhaps the most valid use of SEER is to describe cancer incidence rates and subsequent patient survival. These types of descriptive studies are important because monitoring cancer incidence over time is a critical component to the development of research priorities, screening, and prevention strategies. Analyses of survival rates after initial diagnosis allow assessment of changes in treatment effectiveness