"Chemo Brain" May Affect Half Of Myeloma Patients After Initial Therapy, And Is Worsened By Stem Cell Transplantation
Results from a recent study indicate that many myeloma patients are likely to suffer impaired cognitive function after their initial multiple myeloma therapy, and stem cell transplantation often causes further impairment.
Nearly half of the patients in the study had cognitive impairment, often referred to as ‘chemo brain,’ after receiving initial anti-myeloma therapy. Half of the patients experienced further impairment of cognitive function at one month and again at three months following autologous (own) stem cell transplantation.
The study authors explain that the most common signs of cognitive impairment were problems with learning, memory, and coordination.
In addition, they note that older patients, minorities, those with more advanced disease, more induction cycles, or impaired cognitive function following induction therapy were at greater risk for further cognitive impairment following stem cell transplantation.
The study did not, however, measure cognitive function prior to the start of myeloma therapy or more than three months after stem cell transplantation. Previous studies have indicated that cognitive function slowly improves over many months or even years after transplantation.
Based on their results, the investigators suggest that patients who undergo autologous stem cell transplantation, particularly those who expect to resume work that involves high cognitive demand, be made aware of the risk of cognitive impairment following transplantation and offered counseling or support.
They also recommend that future studies look at the long-term cognitive function of patients undergoing transplantation.
Autologous stem cell transplantation is commonly used in the treatment of multiple myeloma, particularly for patients who are younger and otherwise healthy.
The procedure involves collecting a patient’s own stem cells prior to high-dose chemotherapy. The stem cells are then re-infused back into the patient to replace the healthy stem cells and blood cells destroyed by chemotherapy.
While combinations of chemotherapy, novel drugs, and stem cell transplantation can be effective against multiple myeloma, these treatments can cause cognitive issues such as memory problems or difficulty performing simple tasks.
A previous study has shown that a patient’s ability to perform at work or school immediately declines after undergoing allogeneic (donor) stem cell transplantation, but gradually improves over extended periods of time (see related Beacon news).
However, according to the investigators of the current study, previous studies assessing cognitive function in myeloma patients who underwent autologous stem cell transplantation have been limited by small sample sizes.
Although anecdotal, several Myeloma Beacon patient columnists have also written about their experiences with ‘chemo brain’ during treatment and following stem cell transplantation (see related Beacon columns).
Between 2008 and 2011, researchers from the MD Anderson Cancer Center in Houston enrolled 53 multiple myeloma patients who had recently received induction (initial) therapy and were set to undergo autologous stem cell transplantation. The median age of the patients was 58 years.
The patients had received a median of three to four cycles of induction therapy, with the majority (87 percent) of patients receiving Velcade (bortezomib)-based induction therapy.
All patients were assessed for cognitive function before transplantation, as well as one and three months following transplantation.
The investigators used a wide variety of tests to assess attention, psychomotor speed, learning/memory, language, executive function, and motor function. Patients were also assessed for symptoms of depression. Patients’ scores were then adjusted for age, education, handedness, and gender and compared to published data for the general population.
In addition, all patients in the trial reported to research staff at least weekly the degree of difficulty they had with concentrating and remembering things before and up to one year after transplantation.
Following induction therapy and prior to autologous stem cell transplantation, 47 percent of the patients already showed signs of cognitive impairment, with learning/memory and executive function being the most compromised. Executive function refers to the ability to plan, organize, strategize, execute, and manage time.
In particular, older patients were found to be more likely to have psychomotor speed issues. Psychomotor function refers to simple actions that involve communication between the brain and other body parts, such as throwing a ball or driving a car.
Minorities were more likely to have impaired attention and learning/memory.
Of the 41 patients who were available to be assessed one month following transplantation, 49 percent experienced worse cognitive function after transplantation compared to before transplantation. Specifically, 20 percent of patients declined on one, 10 percent on two, and 20 percent on three measures of cognitive function.
The investigators note that the most common cognitive issues a month after transplantation were learning/memory problems (22 percent to 29 percent of the patients) and motor function (15 percent of the patients).
Of the 29 patients who were available to be assessed three months following transplantation, 48 percent showed cognitive decline compared to their cognitive function one month after transplantation. Specifically, 31 percent of the patients declined on one, 14 percent on two, and 4 percent on three measures of cognitive function.
Similar to the previous two assessments, learning/memory problems (18 percent of the patients) and psychomotor speed (21 percent of the patients) were the most commonly affected functions.
Age, education, disease stage, number of induction cycles, and cognitive impairment prior to stem cell transplantation were all associated with impaired cognitive function three months after transplantation.
The researchers note that only 25 percent of patients displayed stable or improving performance on all cognitive measures throughout the study.
For more information, please refer to the study in the journal Cancer (abstract).
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