Obesity & Poverty Tied to Reduced Breast........

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Obesity and Poverty Tied to Reduced Breast Cancer Chemotherapy

By Judith Groch, Senior Writer, MedPage Today

Reviewed by Jasmer, MD; Associate Clinical Professor of Medicine,

University of California, San Francisco

January 19, 2007

ROCHESTER, N.Y., Jan. 19 -- Fatter, poorer, and less educated breast cancer

patients are more likely to get partial-dose adjuvant chemotherapy, which may

jeopardize their survival, researchers reported.

In a national study, severely obese women (¡Ý 35 kg/cm2) were four times as

likely as lean women to receive less than 85% of the standard adjuvant

chemotherapy dose, found Griggs, M.D., now of the University of

Michigan in Ann Arbor, and colleagues at the University of Rochester.

Much of this was attributable to misapprehensions about the toxicities of the

higher doses of chemotherapy needed for overweight patients, the investigators

reported in the Jan. 20 issue of the Journal of Clinical Oncology.

Also, patients with less than a high school education were three times as likely

to be short-changed, the investigators found.

The researchers studied 764 breast cancer patients treated with a standard

chemotherapy regimen at 115 randomly selected hospitals and physicians' offices

across the country. The data collection, but not the study, was supported by

Amgen through the University of Rochester-based Awareness of Neutropenia in

Cancer Study Group Registry, a prospective, multicenter study of cancer patients

starting chemotherapy.

According to Lyman, M.D., of the University of Rochester, one of the

investigators, 21% of obese and severely obese women received less than 85% of

the standard dose, compared with 10% of the lean women. Moreover, 32% of women

who didn't finish high school received reduced doses, compared with 14% of women

with a high school or college education.

The use of reduced chemotherapy schedules in heavy patients is a consistent

finding in previous studies, Dr. Griggs said. The motivation for this practice,

which violates clinical trial protocols, is most likely physicians' desire to

avoid toxicity, which they believe might accompany the large doses that

patients' weight would indicate.

There appears to be persistent uncertainty among oncologists about the safety of

full weight-based doses despite published research supporting the use of actual

body weight in calculating doses, the investigators said.

The part played by lower socioeconomic status is less clear, they said, but

appears to be physician-driven. The researchers speculated that under conditions

of uncertainty, as is true with chemotherapy, physicians are more likely to be

concerned about a patient's ability to communicate, shorter duration of visits,

less partnership building, and less social talk in physician-patient encounters.

Negotiating a patient through treatment's adverse effects may seem more

straightforward with patients of higher socioeconomic status with whom there is

less social distance, the researchers suggested.

Only one prior study has examined the effect of socioeconomic status on

chemotherapy dose, said Dr. Griggs and colleagues. Black race, increasing age,

co-morbidities, and obesity have all been associated with underdosing for the

first course of chemotherapy and overall lower dose intensity.

Social disparities in breast cancer outcomes and in mortality may be partly the

result of lower chemotherapy doses in the adjuvant treatment of breast cancer,

the investigators said. Efforts to address such prescribing patterns might help

reduce these socioeconomic disparities in breast cancer survival, they added.

The patients, mean age 53.2, had a histologically confirmed diagnosis of

nonmyeloid cancer (stages I, II, or III) and were starting a new

myelosuppressive regimen with at least four planned cycles.

U.S. Census Bureau statistics and the women's zip codes were used to assign the

women to a median household income, and to estimate education level.

Information was also collected about the patients' actual educational

attainment, disease, and treatment, including chemotherapy doses received. The

physicians calculated the standard chemotherapy dose for each patient and

compared it with the dose the patient actually received.

In univariate analysis, individual education attainment, zip code socioeconomic

measures, body mass index, and geographic region were all significantly

associated with intentionally reduced doses of chemotherapy.

In multivariate analysis, controlling for the wide variations of geography,

factors independently associated with reduced doses were obesity (body mass

index of 30-35 kg/cm2) (odds ratio, 2.47; 95% CI, 1.36 to 4.51), severe obesity

(OR, 4.04; CI, 1.46 to 11.19), and education less than high school (OR, 3.07;

CI, 1.57 to 5.99).

A limitation of the study, the investigators said, was the assignment of

socioeconomic status, which was limited to individual education attainment and

zip code rather than street address, the investigators wrote.

The independent association between socioeconomic factors, controlling for

geography, suggests that its impact on dosing is not merely related to local

practice patterns. These results offer an explanation for the disparities in

breast cancer-specific survival in patients in a lower social and economic

bracket and may provide an opportunity to improve patient care and possibly

patient outcome, Dr. Griggs' team concluded.

Action Points

Explain to interested patients that oncologists have found no need to avoid

recommended full-dose chemotherapy regimens on the basis of weight, as suggested

in this review, in obese or severely obese breast cancer patients.

Primary source: Journal of Clinical Oncology

Source reference:

Griggs, JJ, et al " Effect of Patient Socioeconomic Status and Body Mass Index on

the Quality of Breast Cancer Adjuvant Chemotherapy " Journal of Clinical Oncology

2007; 25 (3) doi 10.1200/jco.2006.08.3063.

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SAVE THE DATE: Sunday, April 22, 2007-The Sixth Annual Complementary

Medicine Conference at SUNY New Paltz, New Paltz, NY from 8am to 5pm.

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