Moving to U.S. tied to higher cancer risks

A woman receives radiotherapy in a handout photo.

NEW YORK (Reuters Health) - Hispanic adults who immigrate to the United States may face higher risks of certain cancers than their native countrymen, a new study suggests.

The study, which looked at a database of cancer cases diagnosed in Florida between 1999 and 2001, found that residents of Mexican, Cuban and Puerto Rican origin had overall cancer rates that were at least 40 percent higher than those in their homelands.

But Hispanic residents were not uniform in their cancer patterns, the researchers report in the journal Cancer Epidemiology, Biomarkers and Prevention.

Those of Cuban background, for instance, were similar to non-Hispanic white Americans in regards to a number of cancers -- particularly their rates of cervical and stomach cancers, which were lower than those of other Hispanic groups.

Overall, Puerto Rican men and women had the highest rates of most forms of cancer, while Mexicans tended to have the lowest.

"Hispanics are not all the same with regard to their cancer experience," lead researcher Dr. Paulo S. Pinheiro, of the University of Miami Miller School of Medicine, noted in a written statement.

"Targeted interventions for cancer prevention and control should take into account the specificity of each Hispanic subgroup: Cubans, Puerto Ricans or Mexicans," he added.

For the study, Pinheiro's team analyzed more than 300,000 cases from Florida's central cancer registry, about 10 percent of which were diagnosed in Hispanic patients -- most of whom were born outside the U.S.

The total rate of various cancers was lower for Hispanic adults than for non-Hispanic white and black Americans. Among men, the rate was 11 percent and 17 percent lower than those for white and black men, respectively. Hispanic women's cancer rate was 18 percent lower than non-Hispanic white women's and 2 percent lower than that of non- Hispanic blacks.

Still, compared with data from their countries of origin, Mexican, Cuban and Puerto Rican adults all had elevated rates of cancer overall -- and of some of the most common cancers, including those of the colon, lungs, breast and prostate.

Higher rates of cancer screening and detection in the U.S. may explain part of the increases, according to the researchers, particularly in the case of prostate cancer.

But changes in environment and lifestyle are also likely at work, Pinheiro said.

Immigrants' higher smoking rates, compared with their homeland counterparts, may help account for the higher lung cancer risk, for example. Meanwhile, breast cancer risk may be affected by reproductive factors, like having fewer children or delaying childbirth -- which have been linked to increased breast cancer risk.

Changes in diet and higher rates of obesity after immigration may also be factors, the researchers note.

The findings, according to Pinheiro, suggest that doctors need to discourage Hispanic patients from adopting unhealthy habits that may be more common in the U.S. -- and that immigrants should try to hang on to the healthier parts of their lifestyle in their native countries.

SOURCE: Cancer Epidemiology, Biomarkers and Prevention, August 2009.