Testis cancer: Cognitive decline is possible risk of chemotherapy

August 15, 2008

Findings from a study of testicular cancer survivors add to existing evidence that cognitive impairment is a potential long-term risk of cancer chemotherapy.

Chicago-Findings from a study of testicular cancer survivors add to existing evidence that cognitive impairment is a potential long-term risk of cancer chemotherapy, Swedish investigators reported at the American Society for Clinical Oncology annual meeting.

Results from a study-specific, validated questionnaire showed men who received at least five cycles of cisplatin-based chemotherapy were significantly more likely to have problems with five of seven language-related tasks, compared with those who received no chemotherapy. There were no significant differences comparing the surgery-only controls with subgroups of patients who received one to two or three to four cycles of cisplatin-based chemotherapy.

"Ours is a large study with well-matched groups able to specifically investigate the potential effects of chemotherapy. We believe the information it provides may be useful for counseling patients and particularly to reassure men who report cognitive and language difficulties that their problems may be treatment-related and they are not alone."

Participants in the study were identified through the Swedish-Norwegian Testicular Cancer Project, which has prospectively registered men diagnosed with non-seminomatous testicular cancer since Jan. 1, 1981. Men registered through Dec. 31, 2004, were invited to participate in the study, and the 978 men who returned the questionnaire represented 82% of the nearly 1,200 eligible testicular cancer survivors.

The questionnaire was based on in-depth interviews with chemotherapy-treated cancer patients who discussed difficulties they perceived in daily life.

Results were analyzed for a total of 59 questions, which were categorized into different cognitive domains by a group of psychologists. For the seven language-related questions, three times as many men treated with five or more cycles of chemotherapy had difficulty at least once a week producing similar but incorrect words, saying words in the wrong order, and understanding what people mean. In addition, twice as many men treated with five or more cycles of chemotherapy, compared with the surgery-only group, said words other than intended, and had problems completing sentences at least once a week.

Dr. Skoogh noted that this study was specifically designed to investigate long-term impairment related to chemotherapy.

"Studies conducted sooner after cancer diagnosis and treatment initiation would probably find a higher prevalence of problems, but some of those difficulties may be associated with stress and crisis reactions rather than the chemotherapy," she told Urology Times.

Discussing the paper, Derek Raghavan, MD, PhD, chair and director of Cleveland Clinic's Taussig Cancer Institute, noted the results contribute to understanding of late adverse effects of chemotherapy.

"Those of us who are general oncologists and treat breast cancer patients are well familiar with women who notice a phenomenon of 'chemo brain,' which may involve, for example, an inability to perform calculations or select desired words. However, female patients may be more perceptive than males," he said.

"Dr. Skoogh and colleagues asked the very important question of whether cognitive impairment is a long-term consequence of chemotherapy in men with testicular cancer. Based on their study, the answer is probably yes, at least in some men," Dr. Raghavan said.

The research showed language difficulties were associated with a greater number of cycles of chemotherapy. Researchers also discovered that there is scanty evidence to support use of more than three or four cycles of chemotherapy in men with low- or intermediate-risk non-seminomatous testicular cancer, which underscores the importance of administering additional cycles with caution, Dr. Raghavan noted.

He also suggested the Swedish study might even underestimate the issue of language impairment.

"The enrolled patients represented only about 80% of the population treated, and so there is a potential for case selection basis," Dr. Raghavan said.

He also emphasized that chemotherapy has changed the pattern of cure for metastatic testis cancer dramatically and noted that patients should not refuse chemotherapy for metastatic disease because of fear of potential late toxicity.