Reply to correspondence re: Le et al., Cancer incidence patterns among Vietnamese in the United States and Ha Noi Vietnam

✍ Scribed by Gem M. Le; Scarlett L. Gomez; Christina A. Clarke; Sally L. Glaser; Dee W. West

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: French
• Weight: 36 KB
• Volume: 107
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/ijc.11365

✦ Synopsis

Dear Sir,

We appreciate the comments made by Ngoan et al. 1 in response to our article "Cancer incidence patterns among Vietnamese in the United States and Ha Noi, Vietnam" published in this journal.

The authors raise the point that the age structures of the 2 populations under comparison are substantially different and consequently impact the cancer incidence rates. Because of the well-recognized differences in age structure among the populations under comparison, we used a well-established statistical procedure, age adjustment, to compute cancer incidence rates. 2 Age adjustment allows comparisons among groups with different age structures by removing the effect of age. Thus, incidence rates presented in the paper are not affected by differing age distributions.

The authors also state the comparison of incidence rates between nonrandom samples is limited using the direct method of standardization. However, we used the world standard million population in the direct method of standardization, a standard that is widely used in international comparisons of cancer rates. 3 Using a common standard allows our findings to be compared with those of previously published migrant studies. 4 -6 We extensively addressed the issue of regional variation within Vietnam in our report. We recognize that the population covered by the Ha Noi Cancer Registry may not be comparable to Vietnamese in the United States as these migrants have historically come from southern Vietnam. However, we chose Ha Noi rather than Ho Chi Minh City in south Vietnam as the comparison region for its better data quality and comparability standards that have been met for inclusion by the IARC.