Whether it’s linked to genetics, a cultural factor or something else altogether is unclear, but it’s definitely more than coincidence.
In the largest-ever study of its kind, City of Hope researchers recently found that Asian-Americans show significantly higher survival for stomach cancer than patients from other ethnic or racial groups.
|Joseph Kim (Photo by Walter Urie)|
The researchers analyzed data from the Los Angeles County Cancer Surveillance Program — a registry that gathers information on all new cancer diagnoses made among residents of the county — and found that patients of Asian descent with gastric adenocarcinoma survive nearly twice as long after diagnosis as Latinos; blacks and whites do worst.
Gastric adenocarcinoma is the most common form of stomach cancer, comprising 90 to 95 percent of cases. It’s also the second-leading cancer worldwide and one of the top five causes of cancer death.
The study is the largest ever on racial disparities in stomach cancer.
“We looked at all patients in the county from 1988 to 2006 with gastric cancer, and no matter what the extent of disease or treatment, Asians did best,” said Joseph Kim, M.D., assistant professor in the Department of Surgery and senior author on the study.
|Asian-American stomach cancer patients appear to survive longer overall than patients from other racial or ethnic groups. (Graphic by Alicia Di Rado)|
Kim and his colleagues wanted to explore potential differences in gastric cancer outcomes because survival varies around the globe. Patients in Eastern nations are more than twice as likely to live for at least five years after treatment as those in Western nations.
Surgeons in Asian nations have attributed the better results to their extensive surgeries, but other studies have found no link between surgical technique and outcome.
To try to get to the bottom of it, the City of Hope research team analyzed more than 13,500 cases of stomach cancer in Los Angeles County. The county is an ideal site for study because of its diverse population (Asian-Americans comprise 10 percent of the county’s residents).
Stomach cancer is more prevalent among those of Asian descent due to factors such as diet; researchers believe consumption of smoked, pickled and salted foods increases risk.
Survival for patients with gastric cancer in all stages broke down this way:
- About 28 percent of Asian-Americans survived for five years; typical survival was 15.8 months.
- Latinos had a five-year survival rate of 16 percent and survived a median 8.6 months.
- Among whites, 13.5 percent survived five years with a median 8.1-month survival.
- Blacks had a median survival of 7.7 months and five-year survival rate of 12 percent.
Whether gastric cancer was discovered early or late — and regardless of how it was treated or where it was located in the stomach — Asians still lived longer.
“It’s not really clear why these differences exist, but it’s unlikely to be related to surgical technique,” Kim said. “We suspect there may be differences in tumor biology among the groups.”