In medical research, Asian-American patients have often been treated as a monolith and grouped together with Native Hawaiian and other Pacific Islander (NHPI) patients.1
However, studies have shown that this type of aggregation can hide significant disparities in cancer incidence and outcomes across these patient groups.
For example, researchers have found that patients with Southeast Asian ancestry have the highest risk of developing hepatocellular carcinoma2 and the worst survival after breast cancer.3 Laotian Americans have the highest risk of nasopharyngeal cancer4 and a high risk of death after liver cancer.5
A study of 9 cancers that are common in the United States showed superior survival outcomes among patients with East Asian, South Asian, and Southeast Asian ancestry and inferior outcomes among NHPI patients.6
“Aggregation of data will inevitably run the risk of obscuring differences between groups in any number of ways: country of origin, genetic ancestry, disease frequency, socioeconomic status, patterns of immigration, as well as dietary and cultural practices, just to name a few,” said Alice Yunzi Yu, MD, of Lurie Children’s Hospital of Chicago.
On a broader level, aggregating data from distinct groups leads to a deficit in public awareness and funding that could help solve the health disparities affecting these populations, according to Kekoa Taparra, MD, PhD, of Stanford University School of Medicine in California.
Asian and NHPI Patients Have Different Outcomes
Dr Taparra noted that NHPI patients are often aggregated with Asian patients, even though these groups represent 2 distinct races.1
“Despite this common practice in medical literature, NHPI individuals are not the same as Asian individuals and should never be aggregated together, as this masks the most significant disparities between these 2 races,” Dr Taparra explained.
In a study published last year, Dr Taparra and colleagues examined data from patients with 9 cancers common in the United States.6 The researchers found that patients with East Asian, South Asian, and Southeast Asian ancestry generally had better overall survival (OS) than non-Hispanic White (NHW) patients. Southeast Asian patients with lymphoma were the only Asian group with inferior OS compared with NHW patients.
NHPI patients, on the other hand, did not have superior OS, compared with NHW patients, for any of the 9 cancers. In fact, NHPI patients had inferior OS for oral cavity cancer, lymphoma, endometrial cancer, prostate cancer, and breast cancer.
Dr Taparra and colleagues also examined data from a study in which the 10-year OS rate was 91% for Asian-American and NHPI patients with early-stage breast cancer.7 However, disaggregated data showed a difference in 10-year OS across patient subgroups.
Compared with NHW patients, NHPI patients had a higher risk of death (adjusted hazard ratio [aHR], 1.38), and a lower risk of death was seen for East Asian (aHR, 0.57), South Asian (aHR, 0.66), and Southeast Asian (aHR, 0.78) patients.
Differences Across Asian Subgroups
Research has generally revealed differences in the incidence and outcomes of cancers for patients with East Asian, South Asian, and Southeast Asian ancestry.
A study by Lee et al revealed varying incidences of nasopharyngeal cancer across subgroups of Asian-American patients. For example, the incidence rate ratio, compared with NHW patients, was 14.71 for Laotian patients, 10.73 for Chinese patients, 1.17 for Japanese patients, and 1.04 for Indian/Pakistani patients.4
A 2018 study by Pham et al revealed disparities in hepatocellular carcinoma incidence.2 Patients with Southeast Asian ancestry had rates of hepatocellular carcinoma that were more than 2 times higher than those of other Asian subgroups, and 8 to 9 times higher compared with NHW patients.
A subsequent study by Li et al revealed a higher risk of death due to liver cancer in Kampuchean and Laotian Americans, compared with NHW Americans.5 However, Vietnamese, Chinese, and Korean Americans had a lower risk of death from liver cancer.
“Our studies investigating the most common cancers in the US have found that patients with cancer who identify from areas of East Asia tend to have better overall survival compared with other regions, such as Southeast Asia, likely due to significant differences in socioeconomic status and other social determinants of health that vary between these groups,” Dr Taparra said.
“Additionally, we have found that factors such as time to treatment differ between the groups, particularly Southeast Asians, perhaps due to differences in health literacy or cultural values, explaining, in part, the differences in clinical outcomes,” he added.