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.

Background

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 ^[1] 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 ^[2] columns).

Study Design

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 ^[3] (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.

Results

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 ^[4] (abstract).