Taxanes May Increase Risk for Significant Psychological Symptoms

Taxane-based chemotherapies are increasingly used for the adjuvant treatment of early and locally advanced breast cancer, but new research suggests that they confer a risk for significant psychologic symptoms. According to a study published in the August 1 issue of Cancer, patients who received taxane-based therapy had significantly worse emotional distress and slower psychologic recovery than those receiving a similar regimen without taxanes. The researchers also observed high rates of probable clinical depression among patients who received taxane therapy.

Currently, the underlying reasons for these effects remain largely speculative, according to lead author Lisa Thornton, PhD, a post-doctoral fellow involved in the Stress and Immunity Cancer Project at Ohio State University, in Columbus. One possibility is an underlying immunologic mechanism; cancer treatments, including chemotherapies, can trigger inflammatory reactions. Inflammation is known to produce depression-like symptoms, including low mood, fatigue, irritability, and sleeplessness. "It may be that taxanes trigger this response more strongly and for a longer period of time than other drugs do," said Dr. Thornton. "Other data from our lab suggest that taxanes do stimulate the immune system, so it's possible we may be seeing the after effects of that."

"Until we know more about the underlying mechanism, it would be prudent to counsel patients about the long emotional recovery time, monitor their mood as a routine part of follow-up, and make psychologic treatment available to patients who need it," said Dr. Thornton. "Also, depressive symptoms are not routinely monitored in cancer survivors, and patients may not realize their symptoms could be an after effect of treatment. If they know what to expect, that could significantly help people to cope with the recovery. And for those who need a little extra help, psychologic treatments have been shown to be effective for patients with cancer."

Increased Emotional Stress and Slower Psychologic Recovery

Findings from previous clinical trials have suggested that quality of life declines during taxane therapy, and the decline differs from that observed with other cancer treatments. The primary goal of this case-control study was to compare the short-term (during treatment), moderate-term (2 year), and long-term (up to 5 years) toxicity and quality of life among breast cancer patients who received taxanes and those who did not.

The cohort included 227 patients, accrued between 1994 and 2000, with newly diagnosed, surgically treated stage II or III breast cancer. Of this group, 55 received taxanes as part of their treatment regimens. Patients receiving taxanes experienced a greater number and severity of 6 of the 9 signs or symptoms assessed during their treatment period (4-, 8-, and 12-month assessments). However, from years 2 to 5, there were no differences observed between the 2 groups in any of the 9 signs or symptoms.

The researchers also observed that patients who received taxane agents had significantly worse emotional distress and mental quality of life throughout the treatment period. Their psychologic recovery was significantly slower, requiring an average of 2 years, compared with the 6 to 12 months required by patients who did not receive taxane.

The rates of probable clinical depression were also higher among patients receiving taxanes. In particular, there were statistically significant group differences in depressive symptoms at 12 and 18 months, and a trend toward such at 24 months. The rates of probable depression among patients who did not receive taxanes declined to less than 10% by the 12-month follow-up, whereas the rates in the taxane group remained high (at approximately 20%).

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