A new study says the incidence of "chemobrain," a widely reported side effect in women undergoing chemotherapy treatment for breast cancer, may be overestimated. Researchers found significant deficits in neuropsychological function in breast cancer patients before undergoing chemotherapy. The study was published in the journal Cancer.

While breast cancer remains one of the most common cancers, breakthroughs in the use of chemotherapy protocols with surgery have led to improved survival. However, previous studies have reported these drugs may be linked to permanent cognitive deficits, sometimes called "chemobrain," a side effect that could affect the decision to use chemotherapy for women wanting to return to academic, occupational and social pursuits.

Until now, studies linking chemotherapy to cognitive decline have looked only at post-treatment neurocognitive function, without comparing to pre-treatment function. In the first prospective study to characterize cognitive abilities of breast cancer patients before adjuvant chemotherapy, Dr. Christina A. Meyers and colleagues from the University of Texas M. D. Anderson Cancer Center collected neuropsychological profiles from 84 women with noninvasive breast cancer prior to their treatment with chemotherapy.

Surprisingly, 35 percent of the women demonstrated baseline cognitive impairment with significant deficits in verbal learning and memory prior to chemotherapy. Psychomotor processing speed and attention, non-verbal memory, naming, complex visual tasks and hand fine motor dexterity also trended toward significant impairment compared to the controls.

"Given the current documentation of objective cognitive impairment prior to adjuvant systemic therapy," write the authors, the conclusions of studies reporting high frequencies of cognitive impairment "may overestimate the true incidence of declines in cognitive function secondary to chemotherapy" and dismiss all too easily the impact of cancer itself on neuropsychological function.

SOURCE:
Cancer, June 21, 2004