Breast cancer patients who are less educated and have a lower household income are more likely to receive reduced doses of chemotherapy -- leading to undertreatment for their disease -- new research suggests.
Overweight and obese women are also more likely to receive less chemotherapy.
The report is published in this month's issue of the Journal of Clinical Oncology.
Researchers looked at 764 women with early breast cancer who were enrolled in a prospective, multi-center study of cancer patients starting chemotherapy.
Using U.S. Census Bureau statistics and zip codes, the study authors estimated each woman's household income and poverty status. The women were also interviewed to determine their level of education.
What they found was that women with less education were more than three times as likely as those with more education to receive reduced levels of chemotherapy.
Undertreatment with Chemotherapy "a Broad Problem"
Typically, doctors use a formula -- based on a patient's height and weight -- to determine what dose of chemotherapy patients should receive during treatment. But the women in this study didn't always receive as much chemotherapy as they should have, according to the study.
"What we saw was that women who had not completed high school were far more likely to be started on a lower dose [of chemotherapy]," said study co-author Dr. Gary Lyman, professor of medicine and oncology at the University of Rochester Medical Center in Rochester, N.Y.
"Why that might be, we really don't know," Lyman said. "We are collecting more data and hope to dissect out to the reasons for this undertreatment."
Undertreatment with chemotherapy is a very serious problem for breast cancer patients and cancer patients in general.
This finding sheds light on a very real discrepancy -- women with less money and less education are being given less of the medicine they need.
The study is an important first step in addressing the discrepancies, cancer experts say.
"This study is significant," said Dr. Clifford Hudis, Chief of the Breast Cancer Medicine Service at Memorial Sloan-Kettering Cancer Center in New York.
"Undertreatment of patients with chemotherapy is a broad problem," Hudis said. "It has been called 'killing with kindness," and it is important to understand where and how it happens so that we can address the issue."
Obese Women May Be Undertreated as Well
Women who are overweight are also likely to be under treated with chemotherapy, the new research confirms.
Obesity is controversial as a risk factor for breast cancer; studies haven't shown that obesity causes breast cancer, but obese women are at increased risk of dying from the disease.
Scientists estimate that between 11,000 and 18,000 deaths per year from breast cancer in U.S. women over age 50 might be avoided if women could maintain a Body Mass Index under 25 throughout their adult lives.
The lower survival rates in heavy women may be associated with higher levels of estrogen production in these women.
However, they may not do as well because they are treated differently.
"Many drugs are dosed based on a calculation of the body surface area that uses both height and weight," said Hudis. "For larger people this leads to larger doses, sometimes at levels that concern clinicians."
"This leads them to err in the direction of underdosing to avoid harm."
Although some doctors intentionally underdose their obese cancer patient in an effort to avoid the toxic side effects of chemotherapy drugs, that treatment strategy could actually be putting patients at risk.
"Physicians need to realize that there have been many studies that show that full correct doses have no more side effects [than reduced doses]," said Lyman.
"If you underdose the patients, as happens often, their survival is worsened."
Health Disparities May Play a Factor
One of the reasons for underdosing those with less education relates to their socioeconomic status and the reduced ability to get proper care.
"It's hard to make a conjecture based just on the data we have," said study co-author Eva Culakova, statistician at the University of Rochester Medical Center. "But the socioeconomic level is one of the factors."
"We speculate that physicians have concerns about a patient's ability to tolerate the side effects of chemotherapy and that the physician's uncertainty about a patient's tolerance increases with increasing social distance," said study author Dr. Jennifer Griggs, Associate Professor of Internal at the University of Michigan School of Medicine.
In other words, since physicians in these cases are not on the same social level as their patients, they may make assumptions about the patient's ability to handle the costs and inconveniences of treatment or other factors.
"One might just as well ask why we are willing to give full doses to someone with more education," Griggs said. "It may be that negotiating side effects and continued doses of treatment is easier when there is more shared culture.
"Physicians, driven by a benevolent desire to take the best care of their patient, may view those with less resources as being more vulnerable."
The fact that cancer treatment is challenging for all patients on many other levels also plays a role. And being poor does not help.
"Treatment is a difficult thing," said Lyman. "Patients who are challenged by the system are often the ones that don't have the resources or support system to help them to get through this.
"I don't doubt that among the factors that influence delivery of care is being able to afford it, take time off from work, get to treatment and have family support," he said.
And economic factors prevent some poor patients from even getting treatment. Standard chemotherapy can cost hundreds of dollars a month and can be as high as $4,400 per month for some drugs. But other costs are also involved.
"There are a lot of costs that poor patients can't pay for outside of direct drug and doctor costs," said Lyman.
Patients, Physicians Must Be More Proactive, Say Experts
The best solution to the problem may be more open communication between doctors and their patients.
"My advice is that it is extremely important for patients starting a treatment program to be very open and engaged with their doctors," said Lyman.
"Many women worry about side effects and tell their doctors, 'Don't give me too much chemo,'" said Dr. Marisa Weiss, President and Founder of BreastCancer.org. "Patients need to keep in mind that if you are going to get chemo, you want to get the best quality chemotherapy possible."
Physicians also need to be familiar with the best treatments available and help less educated patients navigate the system.
"Open discussion by all parties of the issue is the way to address this," said Hudis.
"The doctor needs reassurance that the patient understands the need for treatment and the patient needs reassurance that the doctor... with good intentions... is not compromising treatment."