Hispanic women in Puerto Rico who have triple-negative breast cancer share similar disease characteristics with Hispanic women in California, suggesting that race plays a significant role in the presentation of triple-negative breast cancer among Hispanic women.

These study results were presented at the AACR Annual Meeting 2012

"We think the fact that our patients are geographically located outside the mainland and still have the same disease characteristics suggests that the biology of the disease plays a major role in how the disease is expressed in these patients compared with other factors that have been considered like socioeconomic status, access to treatment, etc.," said Edna M. Mora, M.D., associate professor in the University of Puerto Rico School of Medicine department of surgery and the University of Puerto Rico Comprehensive Cancer Center in San Juan, Puerto Rico.

"Based on our results, we speculate that the biology of the disease promotes the tumours to be more aggressive," she said. "Knowing that biology is important, because then we can develop different treatment strategies for the different subtypes of triple-negative cancers."

Overall, Hispanic women have a lower incidence of breast cancer, but among those who develop the disease, prognosis and survival are poor, Mora said.

In this cross-sectional study, the researchers analysed data from 1,082 women with breast cancer who were diagnosed between 2000 and 2005. Mora and colleagues obtained data from hospital cancer registries and through a medical record review.

The prevalence of triple-negative breast cancer was 16.3 percent, which is comparable to the percentage among Hispanics in California, Mora said. Compared with women with HER2-negative, oestrogen receptor-positive disease, patients in the triple-negative group were younger at diagnosis and had larger tumour size, invasive ductal histology and higher tumour grades.

Most importantly, these results showed that the HER2-negative patients whose tumours expressed oestrogen receptors had a dramatically different disease presentation and better outcomes, Mora said.

"When the patient's tumour expressed oestrogen receptor, it made a significant difference in terms of how the patient responds to therapy and behaves in terms of survival," she said.

Source: American Association for Cancer Research