Milestone Study Tracks County Cancer Patterns

The first comprehensive summary of cancer patterns in Los Angeles County paints an unsettling picture of the region’s diverse groups, each plagued in its own way by diseases often brought on or made worse by choice of lifestyle or accident of birth.

The study, to be released today by researchers at USC, found affluent Anglo women suffering disproportionately from breast cancer, Latina women from cancer of the cervix, Japanese-Americans from stomach cancer and Chinese-Americans from cancer of the nasopharynx.

It found that blacks were more likely than others to die of cancer, even when their risk of certain cancers was lower than that of other groups. Though black women are less likely than Anglo women to develop cancer, they are more likely to die of it.

“The publication of this volume . . . is a milestone in our understanding of the complexity of cancer risks among the various subgroups of the population,” wrote John L. Young Jr., chief of the California Tumor Registry, in an introduction to the 80-page report.

“The ability to identify high and low risks of cancer among the various Asian communities is of particular importance and represents a base line against which future risks can be measured as the newer immigrant groups become assimilated into the American lifestyle,” he wrote.

The study, based on data collected by the Los Angeles regional office of the tumor registry, examines all cancer diagnoses and deaths reported in the county between 1972 and 1987. For the first time, it analyzes data by race, ethnicity, age and sex.

Many of the findings in the study, by Dr. Ronald K. Ross and Leslie Bernstein of the Kenneth Norris Jr. Comprehensive Cancer Center, are consistent with patterns observed elsewhere. They offer an opportunity to tailor cancer-prevention programs to groups with particular needs.

In general, cancer rates were highest among black men and second-highest among Anglo men. Among women, Anglos had the highest rates. For both sexes, cancer rates among Latino whites, Chinese-Americans and Japanese-Americans were 30% to 40% lower than those of blacks or Anglos.

As is true nationally, lung cancer was the most frequently diagnosed cancer among men. It was also the most common cause of cancer death. Only among Latino and black men was prostate cancer more common than lung cancer.

Women of every racial and ethnic background had higher rates of breast cancer than any other cancer--two to three times higher than the second-ranking cancers. For Latinas, invasive cervical cancer ranked second; for Anglos, lung cancer; for black women, colon cancer.

Here are some of the more striking findings of the study:

* Stomach cancer rates were twice as high among Japanese-Americans living in the county than for any other group. Anglos had the lowest rates. The researchers said salt intake appears to determine stomach cancer risk, while cigarette smoking may also play a role.

* Liver cancer, relatively rare in the county, was most common among Chinese-American and Japanese-American men. The major cause of liver cancer is chronic infection with the hepatitis B virus, the prevalence of which, the researchers said, is highest among Asians and may be passed from one generation to the next.

* While lung cancer was the top cause of cancer deaths in men and recently surpassed breast cancer as the leading cause in women, the researchers said cigarette smoking accounted for nearly 90% of all cases, while air pollution “makes a relatively small contribution.”

* Rates of breast cancer, which tend to be highest in Western industrialized countries and low in Asia, Latin America and Africa, were highest among Anglo women. Risk factors are known to include early menstruation and delayed childbearing. Diet is also suspected.

* Invasive cervical cancer was one of the few cancers that Latinas were more likely than other groups to get. Black women also had high rates of cervical cancer, which is believed to be caused by a virus. Major risk factors include early intercourse and multiple sexual partners.

* Rates of cancer of the nasopharynx, the portion of the pharynx behind the nasal cavity and above the soft palate, were 10 times higher among Chinese-American men and women than among any other group. The primary risk factor for that cancer is consumption of Cantonese salted fish.

* Cancers of the oral cavity--such as the lip, tongue, gums and mouth--were more common among men than women and most common among Anglos and blacks. Cancer of the lip was most common among Anglos, apparently because of exposure to sunlight.

* Esophageal cancer, a particularly lethal form of the disease, was three times more common among blacks than among other groups. Cigarette smoking and heavy alcohol consumption are believed to account for 80% to 90% of esophageal cancers in the county. Dietary factors may also play a part.