The TAILORx study provided a novel opportunity to prospectively assess patient-reported cancer-related cognitive impairment (CRCI) among women with early breast cancer who were randomly assigned to chemoendocrine therapy (CT+E) versus endocrine therapy alone (E), allowing researchers to measure the unique contribution of chemotherapy to CRCI. The design of the phase III TAILORx trial (ClinicalTrials.gov Identifier: NCT00310180), which was conducted in women with early stage, hormone receptor–positive, HER2-negative, node-negative breast cancer, provided the opportunity to separately evaluate the contribution of adjuvant chemotherapy to perceived cognitive impairment in the setting of a randomized study.
A substudy of TAILORx involved a comparison of patient-reported outcomes regarding cognitive function in two balanced study arms in which patients classified as being at intermediate risk of disease recurrence were randomly assigned to receive adjuvant endocrine therapy with or without adjuvant chemotherapy. The emphasis of the substudy's primary endpoint was on changes in patient-reported cognitive function using the validated Functional Assessment of Cancer Therapy-Cognitive Function (FACT-Cog) version 3 tool, which was administered at baseline and at 3, 6, 12, 24, and 36 months following initiation of treatment.
Of the 579 patients with baseline FACT-Cog assessments, corresponding data at 3, 6, 12, 24, and 36 months were accessible for 454, 469, 458, 476, 384, and 383 patients, respectively. In the chemotherapy-based study arm, 70% and 20% of patients were treated with docetaxel plus cyclophosphamide and anthracycline-based regimens, respectively.
With regard to endocrine therapy, almost 63% of patients received an aromatase inhibitor while the remaining patients were treated with tamoxifen. At the 3-month assessment, 36.7% and 26.3% of patients treated with and without chemotherapy versus no chemotherapy reported cognitive impairment (P <.001). While a significant variance in patient-reported cognitive impairment was also observed when these respective groups were compared at 6 months (35.5% vs. 30.7%; P = .02), it was no longer observed at 12 months (37.7% vs. 35.3%) and after that time.
At the conclusion of the study, the researchers noted, “The trajectories of longitudinal FACT-Cog [perceived cognitive impairment] change scores by treatment arm converged over time largely because the [endocrine] arm reported a gradual increase in cognitive impairment at 12 months that persisted at 24 and 36 months.”
The scientists also remarked that neither patient age nor menopausal status was linked with variations in perceived cognitive impairment. With regard to their findings, the researchers concluded that adjuvant CT+E is related to considerably greater CRCI compared with E at 3 and 6 months. These variances subsided over time, with no substantial differences observed at 12 months and beyond. These findings indicate that chemotherapy produces early, but not prolonged, cognitive impairment relative to E, offering encouragement to clinicians and to patients in whom adjuvant chemotherapy is indicated to decrease recurrence risk.
