Racial Disparities Exist In Radiation Therapy Rates For Early Stage Breast Cancer

Black women are less likely than white women to receive radiation therapy after a lumpectomy, the standard of care for early stage breast cancer, according to a new study by researchers at The University of Texas M. D. Anderson Cancer Center.

The largest of its kind and the first to examine such racial disparities in radiation therapy, the study was published today in Cancer. It was first presented at the 2008 American Society of Clinical Oncology (ASCO) Breast Cancer Symposium.

Led by Grace Li Smith, M.D., Ph.D., a postdoctoral fellow in M. D. Anderson’s Department of Radiation Oncology, the researchers reviewed the Medicare records of more than 37,000 patients diagnosed with early stage breast cancer in 2003.

“Although there have been smaller studies of racial disparities in breast cancer care, no prior research has examined the differences across the nation in the rates of radiation therapy after lumpectomy between whites and blacks,” said Smith, the study’s first author. “The national Medicare database, because it’s so comprehensive, allowed us to determine the extent to which racial disparities in radiation therapy affected patients across the country.” Read more

Variable Doses Of Radiation Raise Safety Concerns For CT Procedures

Radiation doses from common CT procedures vary widely and are higher than generally thought, raising concerns about increased risk for cancer, according to a new study led by UCSF imaging specialists.

“In day-to-day clinical practice, we found significant variation in the radiation doses for the same type of computed tomography procedures within institutions and across institutions,” said lead investigator Rebecca Smith-Bindman, MD, a professor of radiology at UCSF. “Our results highlight the need for greater standardization because this is a medical safety issue.”

Computed tomography imaging, known as CT, is a diagnostic procedure that uses special x-ray equipment to obtain cross-sectional pictures of the body that provide detailed images of organs, bones, and other tissues. CT is associated with higher radiation exposure than conventional x-rays, yet radiation dosages that patients receive from the newer CT scanners have gone largely unregulated, according to Smith-Bindman, who also is a UCSF professor of epidemiology and biostatistics and obstetrics, gynecology and reproductive sciences.

“Our study provides some initial data documenting the doses that patients receive when they undergo actual CT examinations and this is different than the doses when phantoms — sophisticated plastic models typically used to quantify CT scanner dose — are used. We believe documenting the actual doses that patients are exposed to is the first step to reducing those doses and any attendant risk,” she emphasized. Read more

Studies Quantify Radiation Doses, Cancer Risks From CT Scans

Doses of radiation from commonly performed computed tomography (CT) scans vary widely, appear higher than generally believed and may contribute to an estimated tens of thousands of future cancer cases, according to two reports in the December 14/28 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

CT scans have become increasingly common in the United States-about 70 million were performed in 2007, up from 3 million in 1980, according to background information in one of the articles. “While CT scans can provide great medical benefits, there is concern about potential future cancer risks because they involve much higher radiation doses than conventional diagnostic X-rays,” the authors of one report write. For example, a chest CT scan exposes the patient to more than 100 times the radiation dose of a routine chest X-ray. “The risks to individuals are likely to be small, but because of the large number of persons exposed annually, even small risks could translate into a considerable number of future cancers.”

It is important to understand how much radiation medical imaging delivers to help balance benefits and risks, the authors note. In one paper, Rebecca Smith-Bindman, M.D., of the University of California, San Francisco, and colleagues studied 1,119 patients undergoing the 11 most common types of diagnostic CT scans at four area institutions in 2008. Using hospital records, they calculated the radiation dosage involved with each scan and then estimated lifetime risks of cancer that could be attributed to those scans.

Radiation dosage varied widely between different types of CT studies; median (midpoint) doses ranged from 2 millisieverts for a routine head CT scan to 31 millisieverts for a multiphase abdomen and pelvis scan. “Within each type of CT study, effective dose varied significantly within and across institutions, with a mean [average] 13-fold variation between the highest and lowest dose for each study type,” the authors write. Read more

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