I have heard the term "chemo brain" used in casual conversation for at least a couple of years. However, it turns out that there is a solid scientific basis for the condition (see: Chemo Brain May Last 5 Years or More). This makes sense given the broad, multiorgan effects of many chemotherapeutic agents. Below is an excerpt from a recent article on this topic:
“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...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....“The real issue here [said the lead author or the article] 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....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....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 idea of "chemo brain" certainly resonates on the web with my Google search for the term yielding 178,000 results. I can understand how patient complaints about fuzzy thinking may occasionally be dismissed by physicians given the complexity of cancer care. Lucking, the newly emerging field of cancer survivorship has resulted in far greater recognition of the broad, mind-and-body effects of cancer treatments (see: Cancer Survivorship, an Emerging Subdiscipline in Oncology). I don't know the extent to which medical research on "chemo brain" has identified the specific neurophysiologic mechanisms behind the change. From a very simplistic perspective, it make sense to me that such symptoms could last for five years or more. Some of the body's cells such as the epithelium lining the GI tract are very short-lived. By way of contrast, neurons have very long lives. It may thus take them a prolonged period of time to recover from the toxic effects of chemotherapeutic agents after the cessation of therapy.
::Update on 5/10/2011 @ 7:45 p.m.