Abstract
BACKGROUND: Research has found that patients treated for cancer generally have an increased risk for cognitive problems. However, many studies have focused on cognitive performance of cancer patients under the age of 65 who received chemotherapy treatment. Less studied is the extent to which cancer diagnosis may be associated with cognitive impairment as a late effect for older adults. METHODS: In this retrospective, co-twin design study, twin pairs 65 years of age and older discordant for cancer were identified from the Swedish Twin Registry. A pair was included if both twins participated in cognitive screening, and the twin with the cancer history was screened at least 3 years after cancer diagnosis and treatment. RESULTS: Female, but not male, survivors of cancer were significantly (odds ratio = 2.42, 95% confidence interval = 1.23-4.74) more likely to exhibit cognitive impairment 3 or more years after cancer diagnosis and treatment as their co-twin without a history of cancer. In particular, risk was higher among survivors of gynecologic cancers (odds ratio = 10.00, 95% confidence interval = 1.28-78.11) and those who had treatments directly or potentially affecting ovarian functioning (odds ratio = 13.00, 95% confidence interval = 1.70-99.36) compared with their respective co-twins. CONCLUSIONS: These findings suggest that localized treatments and other cancer-related factors should be explored as determinants that underlie the association between cancer diagnosis and long-term cognitive impairment.