To the Editor:
As testicular cancer incidence rates among white men have been increasing in the United States for over half a century,1 we feel it is critically important to monitor the trends among other U.S. racial and ethnic groups. We, therefore, read with great interest the companion articles on testicular cancer patterns published recently in your journal.2,3 We were puzzled, however, by the case counts and incidence rates presented in the manuscripts. As a result, we wonder whether the survival analyses have reached accurate conclusions.
In the paper on testicular cancer patterns among ‘Asian-American’ men,2 the Methods section states that the data were drawn from the SEER-9 registries for the years 1973 to 2000. SEER did not provide population counts for Asians/Pacific Islanders prior to 1992, however, so we are unsure how the incidence rate for Asian-American men (reported as 1.1/100,000) was calculated. We noted, however, that the manuscript reported 617 cases among Asian-Americans. This count matches the sum of cases reported among both American Indians/Alaska Natives (n=85) and Asians/Pacific Islanders (n=532) in the “Other” category for the years 1973-2000. We also noted that the reported incidence rate among white men (3.2/100,000) did not match the rate reported in the SEER database for 1973-2000 (Table 1, below). In addition, the distributions of testicular cancers by histologic type and stage are not consistent with the distributions that we have been able to determine. Given these concerns, we wonder whether the survival analysis should be re-examined.
Table 1.
All testicular cancers by race, SEER-9 registries
| White | Black | Asian/Pacific Islander | |
|---|---|---|---|
| 1973-2000 | |||
| Number of testicular cancers | 14,786 | 341 | 532 |
| Incidence rate per 100,000 men | 5.4 | 1.1 | * |
| 1985-2000 | 10,003 | 239 | 419 |
| Number of testicular cancers | 6.0 | 1.1 | * |
| Incidence rate per 100,000 men |
rate cannot be calculated due to absence of population estimate
Data Source: Surveillance, Epidemiology, and End Results (SEER) Program (www.seer.cancer.gov) SEER*Stat Database: Incidence - SEER 9 Regs, Nov 2002 Sub (1973-2000), National Cancer Institute, DCCPS, Surveillance Research Program, Cancer Statistics Branch, released April 2003, based on the November 2002 submission.
In the paper on testicular cancer patterns among African-American men,3 the Methods section notes that the data are derived from the SEER-9 registries for the years 1985 to 2000. However, the reported counts of cases (white men=14,239; black men=326) are too large for this interval; the counts reported are more similar to those for the years 1973-2000 (Table 1). In addition, the incidence rates reported in the manuscript do not match the rates shown in Table 1 below. As with the report on Asian-American men, the breakdowns of cancers by histology and stage are not consistent with what we have been able to determine in the SEER database. Perhaps these issues could be resolved if the authors could clarify the years, registries, morphologic codes and SEER databases that were used in the two manuscripts.
The incidence of testicular germ cell tumors is certainly increasing among white men and has recently begun to increase among black men.4 As a result, interest in testicular cancer in other ethnic and racial groups may be of substantial interest to your readers. Therefore, we feel it is important to re-examine the recently reported data to ensure that an accurate portrait of testicular cancer is presented. At present, the reader of both papers would erroneously conclude that Asians/Pacific Islanders are at lower risk of testicular cancer than are African-Americans. In fact, during the interval 1996-2000, the rate of testicular cancer in the SEER-12 registries was 2.1/100,000 among Asian-Americans in contrast to the rate of 1.4 among African-Americans.5
Footnotes
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References
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