"Our goal was to do a comprehensive analysis, looking at factors such as socioeconomic status, co-morbidities, access to care, age, insurance status and others," said lead study author Mousumi Banerjee, a researcher at the University of Michigan School of Pubic Health. "When we adjusted for these, there was still a difference in the group with regional disease."
In women with regional-stage disease, whites were more than three times as likely to have received adjuvant chemotherapy and more than 4½ times more likely to have received adjuvant Tamoxifen. Banerjee said, "They were definitely noticeable differences."
Although the differences in treatment were cause for concern, there were some encouraging signs as well in the data.
Previous studies had shown differences between blacks and whites in rates of "breast-conserving" surgeries such as lumpectomy and adjuvant radiation — differences that were not seen in this study. There were also no significant differences seen in rates of Tamoxifen or chemotherapy use for local-stage disease.
"Usually surgery is part of the treatment," said Dr. Beverly Moy, a medical oncologist at the Massachusetts General Hospital. "But for some cancers, it is completely equivalent to do mastectomy versus lumpectomy plus radiation. Given an option, most women would choose keeping their breast. So it was nice to see similar rates of mastectomy and breast-conserving therapy (between blacks and whites) in this study."
Most experts were not surprised by the results of the study, but stated that figuring out why the differences existed would be difficult.
"It is sometimes very difficult to determine whether disparities are due to race or other factors," said Moy. "But in my opinion, race is a very important factor to consider."
"It is probably multifactorial," said Dr. Herbert Smitherman Jr., assistant dean of community and urban health at the Wayne State School of Medicine in Detroit. "The choices that people make are clearly a composite expression of their social and cultural circumstances, their conditions of living and the conditions of their community."
Smitherman adds that one factor may be physicians' ability to communicate effectively with their patients.
"There has been some literature showing that physicians' perception of the patient may be affected by race," said Smitherman. "This includes perceptions of patients' ability to understand choices, a sense of affiliation with patients and the ability to engage patients."
"When we walk into a patient's room, it's not like there's pixie dust and we leave everything back at the door."
Kendra Schwartz, study co-author and professor of family medicine at Wayne State, said this possibility highlights the need for physicians to be more cognizant of their interactions with members of a different race.
"We really need to ask the patient explicitly — 'what have you been told? What are your feelings about the treatment options?'" she said. "There are often people who initially don't want chemotherapy because of side effects, but if they are educated about how therapies improve survival, things can change."
On the other side of the patient-doctor relationship, some worry that a history of distrust of the medical establishment among members of the black community may also be affecting patients' medical decision-making.