Original article
Incidence trends in primary malignant penile cancer

https://doi.org/10.1016/j.urolonc.2006.08.029Get rights and content

Abstract

Objective

To examine trends in the incidence of primary, malignant penile cancer in the United States.

Methods and materials

A total of 1,817 men with primary, malignant penile cancer diagnosed between 1973 and 2002 from the Surveillance, Epidemiology and End Results Program Public-use data were used for analysis. Incidence rates were calculated by clinical and demographic variables of interest and decade of diagnosis (1973–1982, 1983–1992, and 1993–2002) using Surveillance, Epidemiology and End Results-Stat 6.1, and trends were examined using the annual percent change statistic. Additional incidence calculations were performed to examine further racial/ethnic differences.

Results

The overall incidence of primary, malignant penile cancer from 1973 to 2002 was 0.69 per 100,000. Incidence decreased significantly over time: 0.84 per 100,000 in 1973–1982 to 0.69 per 100,000 in 1982–1992 to 0.58 per 100,000 in 1993–2002. Incidence increased with increasing age at diagnosis. The majority of cases had squamous cell carcinomas, graded as I or II, and originated at the glans penis. Incidence of unknown grade primary, malignant penile cancer decreased significantly over the last 30 years, as did incidence of primary site penis, not otherwise specified primary, malignant penile cancer. The incidence of regional stage disease also increased over time. From 1993 to 2002, White Hispanics had the highest incidence rates (1.01 per 100,000) followed by Alaska Native/American Indians (0.77 per 100,000) and Blacks (0.62 per 100,000).

Conclusions

The overall incidence of primary, malignant penile cancer in the United States has decreased, and these rates varied by race/ethnicity. Incidence rates increased with increasing age at diagnosis, and the incidence of regional stage disease increased over time, while incidence of unknown grade primary, malignant penile cancer decreased over the last 30 years.

Introduction

Primary, malignant penile cancer is a rare disease representing 0.3% to 0.5% of U.S. male malignancies [1]. Penile cancer incidence in developed countries, such as the United States or Europe, is less than 1.00 per 100,000 [2]. In 2006, it is estimated that there will be 1,530 new cases of penile and other male genital cancers diagnosed in the United States [3]. Worldwide geographic variation in primary, malignant penile cancer incidence is evident and could be caused, in part, by differences in hygienic, social, and religious practices [4].

There have been a number of risk factors identified for primary, malignant penile cancer, including circumcision, tobacco use, and human papillomavirus (HPV) status [5], [6], [7], [8]. The strongest, most consistently reported risk factor associated with an increased risk of disease is a lack of neonatal circumcision [6], [7]. More recently, primary, malignant penile cancer has been associated with the presence of the HPV, which was present in 15% to 80% of patients with primary, malignant penile cancer and thought to account for 50% of all penile cancers [9], [10]. Prognosis after penile cancer diagnosis is very good, with only an estimated 280 deaths occurring in 2006 [3], and is significantly affected by stage, grade, and lymph node involvement.

Our knowledge to date about primary, malignant penile cancer is largely from case series studies at single institutions only, making generalizability of these data difficult. The current literature lacks definitive population-based data on the overall incidence of primary, malignant penile cancer as well as trends over time. Therefore, our study objective was to characterize overall primary, malignant penile cancer incidence and trends in it in the United States using a population-based data set. The Public-Use data from the population-based Surveillance, Epidemiology and End Results (SEER) Program is an easily obtainable population-based data set of incident cancer cases diagnosed between 1973 and 2002 in the United States. These data cover approximately 26% of the United States and are thereby representative of the greater U.S. population [11]. Using population-based data allows for unbiased estimates and generalizability of results to the entire U.S. population.

Section snippets

Study population

A total of 1,817 men with primary, malignant penile cancer diagnosed between 1973 and 2002 from the SEER Public-use data using cases from the SEER 9 registries were used for analysis. The SEER Program is a national cancer surveillance program established by the National Cancer Institute that collects data on all incident cancer cases from 14 population-based cancer registries and 3 supplemental registries covering approximately 26% of the U.S. population [11], representative of national

Results

There were 1,817 newly diagnosed cases with primary, malignant penile cancer between 1973 and 2002 in the SEER Public-Use data: 609 cases from 1973 to 1982, 603 cases from 1983 to 1992, and 605 cases from 1993 to 2002. Overall, the incidence of primary, malignant penile cancer increased with increasing age (P < 0.05), in which men 75–84 years old (3.80 per 100,000) and men 85 years and older (5.13 per 100,000) had the highest incidence rates (Table 1). Blacks had a significantly higher

Discussion

Between 1973 and 2002, the overall age-adjusted incidence rate for primary, malignant penile cancer decreased over time in the United States (P < 0.0001). Other studies have also shown this finding among different populations worldwide [13], [14]. One plausible explanation for this decrease is an overall improvement in hygienic standards over time, including a possible increase in circumcision practices [1], [13]. Increasing age is a critical risk factor for the increased incidence of penile

Conclusions

The incidence of primary, malignant penile cancer decreased significantly in the United States for men diagnosed between 1973 and 2002. These rates increased with increasing age at diagnosis and varied by race/ethnicity, as well as other important variables of interest, such as grade and stage of tumor. Much of the knowledge about incidence of primary, malignant penile cancer is from hospital-based case series only, not from population-based studies or cancer registries. Using population-based

References (22)

  • J.R. Daling et al.

    Penile cancer: Importance of circumcision, human papillomavirus and smoking in in situ and invasive disease

    Int J Cancer

    (2005)
  • Cited by (0)

     Support for J.S.B.-S. by National Cancer Institute grant number K07 CA91849.

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