Source: New York Times

“Chemo brain,” the foggy thinking and forgetfulness that cancer patients often complain about after treatment, may last for five years or more for a sizable percentage of patients, new research shows.

The findings, based on a study of 92 cancer patients at Fred Hutchinson Cancer Research Center in Seattle, suggest that the cognitive losses that seem to follow many cancer treatments are far more pronounced and longer-lasting than commonly believed.

The study, published in The Journal of Clinical Oncology, is a vindication of sorts for many cancer patients, whose complaints about thinking and memory problems are often dismissed by doctors who lay blame for the symptoms on normal aging or the fatigue of illness.

“It’s clearly established now that chemo brain does exist and can continue long-term,” said Karen L. Syrjala, co-director of the Survivorship Program at Fred Hutchinson and the study’s lead author. “The real issue here is that recovery from cancer treatment is not a one-year process but a two- to five-year process. People need to understand the extent to which the cells in their bodies have really been compromised by not only the cancer, but also the treatment.”

The 92 patients in the study had all undergone chemotherapy as part of bone marrow or stem cell transplants to treat blood cancers. Although the range of effects of different cancers and treatments probably varies, researchers said the finding that cognitive recovery can take five years or more is likely to apply to breast cancer patients and patients who have undergone chemotherapy for other types of cancer.

The patients in the study were compared with a case-matched control, like a friend or sibling of the same age and gender who had never undergone cancer treatment. Both groups were given a battery of tests to assess memory and motor skills. The tests included a number of memory and word tests, like trying to recall a list of words or coming up with as many words as possible that all start with the same letter. Tests to match numbers and symbols and timed dexterity tests, in which thin pegs were to be placed into holes, were also included.

Comparing the test results of the cancer patients with those of the matched controls, the researchers found that among cancer survivors, most of the cognitive problems are largely temporary but may persist for five years or longer. Patient recovery generally followed a bell curve, with some showing improvement after a year, while others took two, three or more years to recover.

Dr. Syrjala said the good news is that information processing, multitasking and executive function skills all seemed to recover within five years.

“One of the things people complain a lot about during treatment is word finding, where you know the word, it’s a tip-of-the-tongue experience, but they can’t come up with it,” said Dr. Syrjala. “We hear that so frequently during treatment. The happy news in this data is that that piece of cognitive function does recover, but it usually takes longer than a year.”

However, verbal memory and motor skill problems continued after five years among a large group of patients. Although some neurocognitive deficits are expected to occur with natural aging, the percentage of cancer patients who still had cognitive and dexterity problems at five years was 41.5 percent, twice as high as the 19.7 percent reported in the control group.

Although the news of long-term cognitive problems may be disheartening to patients, it’s important for families and patients to know that recovery can take a while. More important, patient treatment plans should include the teaching of coping skills to compensate for potential cognitive losses.

“The first step is to set realistic expectations for people,” said Dr. Syrjala. “It’s not just patients, but their families and employers who need to realize that their brains aren’t processing as rapidly.”

Many of the cognitive deficits were relatively mild and easily addressed with coping skills like note taking or strategies to improve focus.

“We all lose memory with time and learn to compensate,” Dr. Syrjala said. “These patients just have to recognize that their brains are perhaps not as finely tuned as they were before they were diagnosed with their cancers, but they can compensate very effectively.”