Tuesday, December 13, 2011

Radiation can also cause 'chemo brain,' study suggests

Chemotherapy is not solely to blame for the mental fog, commonly called chemo brain, that some breast cancer patients complain about after treatment, a new study suggests.

Radiation therapy, another widely used cancer treatment, is another potential culprit behind the memory lapses and concentration problems that affect some breast cancer patients - and symptoms can last several years after treatment is finished, researchers have found.

"Everybody has been calling this chemo brain, but it's not necessarily just in people who have been exposed to chemo-therapy," said Paul Jacobsen, senior author of the study and researcher at the Moffitt Cancer Centre in Florida.

The study, published Mon-day in the peer-reviewed medical journal Cancer, looked at breast cancer survivors who had been treated with chemotherapy, radiation or both treatments for three years after finishing treatment.

"We really found in our study that our focus on mental abilities was not limited to women with chemotherapy," said Jacobsen. "In fact, we found a similar pattern in women who were treated only with radiation therapy."

Radiation therapy involves a machine using high-energy rays directed specifically at an affected area to destroy cancer cells.

Chemotherapy involves one or a combination of drugs that work together to kill cancer cells. Chemo is given either through pill form or intravenously directly into the blood stream where it circulates throughout the body.

The study's findings are surprising, said Jacobsen, as the researchers did not anticipate radiation therapy directed at the chest would affect the brain.

"We were not expecting that," he said. "We were thinking that radiation is a localized treatment, and that radiation treatments would look much like the healthy controls."

The study involved 62 breast cancer survivors who had been treated with chemotherapy, 67 breast cancer survivors treated with radiotherapy only, and 184 healthy women with no cancer history.

The researchers had the women take a series of tests to gauge their memory, mental processing speed, attention and concentration abilities.

"What these tests all have in common is they draw on mental flexibility," he said. "The more that you are thinking in a flexible manner, the better you can perform on this type of test."

To rule out other factors that can affect mental processing abilities, like age and intellectual skills, the researchers included a healthy control group with similar age ranges and education levels as the breast cancer patients.

The researchers also did not find a link between hormone therapy drugs, like Tamox-ifen, that prevent breast cancer recurrence and memory or concentration problems.

While earlier studies have con-firmed the connection between chemotherapy and mental cloudiness, this was the first study to also include a group of patients who had undergone radiation treatment only.

It is also the only study to follow breast cancer patients for three years after treatment, said Jacobsen.

Jacobsen said it was alarming to see how long the problems with memory and concentration persisted for breast cancer survivors after their cancer treatment ended.

As the study only followed the women three years out of treatment, Jacobsen could not say how long memory and concentrations problems continue to persist.

However, he said most of the cognitive changes some women experience after chemotherapy or radiation are not often debilitating problems.

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