UH Manoa researcher reports cancer mortality high among Polynesians
More Native Hawaiians, Maoris, and other Polynesians die at higher rates from cancer compared to whites of European ancestry who settled in the Pacific islands, according to a report on worldwide cancer disparities to be published in the May 2008 issue of the "The Lancet Oncology," a monthly medical research publication focusing on the latest developments in cancer. Dr. Loïc Le Marchand, director of the Epidemiology Program of the Cancer Research Center of Hawaiʻi (CRCH), is among the contributors of the report.
"Education regarding cancer screening programs, diet, and smoking could help address this problem," said Dr. Le Marchand. "With these data, we can help advocate for more funding to support culturally appropriate programs, including education and better health care to help individuals quit smoking or make cancer treatments more available to those who need it. These would lower the cancer burden in the Polynesian communities."
Led by Dr. Gabi Dachs of the University of Otago in Christchurch, New Zealand, Dr. Le Marchand and the other collaborating scientists studied cancer incidence, survival, and mortality across Polynesian populations scattered across a vast triangle in the Pacific from Hawaiʻi in the north, to Easter Island in the east, and New Zealand in the south.
The studies found that Native Hawaiians, Maoris, and Pacific Islanders have higher overall cancer mortality rates than whites living in the same areas. Native Hawaiians smoke slightly more than whites, but have a significantly higher risk of getting lung cancer for the same smoking history, suggesting they are more susceptible to the carcinogenic properties of cigarette smoke.
In New Zealand, cervical and uterine cancer in women, and stomach and testicular cancers in men were among the top five most common cancers in Maori, but not in white populations. Despite lower incidences of breast and prostate cancer, proportionally more Maori and Pacific Islanders succumb to these diseases than whites.
Lower income and socioeconomic status were associated with higher cancer mortality, and Maori and Pacific peoples in New Zealand have generally lower incomes than their white counterparts. Infectious agents, such as Hepatitis B, known to cause liver cancer and human papilloma virus (HPV) related to cervical cancers, have a higher incidence among Maori and Polynesian peoples compared to whites.
Late diagnosis may be an important factor in explaining the high mortality rates. Maori people generally present with more advanced stages of cancer than do whites, and screening programs, such as for breast cancer, cover more white women (62 percent) than Pacific women (42 percent) or Maori women (41 percent). Similar observations were made for Native Hawaiians in Hawaii.
Because of the scarcity of data on cancer in many Polynesian populations, the actual incidences and mortality rates for cancer may be under reported, the reports‘ authors say. Better data are also needed on stage of disease, ethnicity and treatment for specific island populations. "Evidence exists for a benefit of culturally appropriate education on screening programs, diet, and smoking, all of which could lower the cancer burden in Polynesian communities," the report concluded.