Cognitive Function in Patients With Colorectal Cancer Who Do and Do Not Receive Chemotherapy: A Prospective, Longitudinal, Controlled Study

Chemotherapy and Post-traumatic Stress in the Causation of Cognitive Dysfunction in Breast Cancer Patients

Background

Cancer-related cognitive dysfunction has mostly been attributed to chemotherapy; this explanation, however, fails to account for cognitive dysfunction observed in chemotherapy-naïve patients. In a controlled, longitudinal, multisite study, we tested the hypothesis that cognitive function in breast cancer patients is affected by cancer-related post-traumatic stress.

Methods

Newly diagnosed breast cancer patients and healthy control subjects, age 65 or younger, underwent three assessments within one year, including paper-and-pencil and computerized neuropsychological tests, clinical diagnostics of post-traumatic stress disorder (PTSD), and self-reported cognitive function. Analysis of variance was used to compare three groups of participants-patients who did or did not receive chemotherapy and healthy control subjects-on age- and education-corrected cognitive performance and cognitive change. Differences that were statistically significant after correction for false discovery rate were investigated with linear mixed-effects models and mediation models. All statistical tests were two-sided.

Results

Of 226 participants (166 patients and 60 control subjects), 206 completed all assessment sessions (attrition: 8.8%). Patients demonstrated overall cognitive decline (group*time effect on composite z -score: -0.13, P = .04) and scored consistently worse on Go/Nogo errors. The latter effect was mediated by PTSD symptoms (mediation effect: B = 0.15, 95% confidence interval = 0.02 to 0.38). Only chemotherapy patients showed declined reaction time on a computerized alertness test. Overall cognitive performance correlated with self-reported cognitive problems at one year ( T = -0.11, P = .02).

Conclusions

Largely irrespective of chemotherapy, breast cancer patients may encounter very subtle cognitive dysfunction, part of which is mediated by cancer-related post-traumatic stress. Further factors other than treatment side effects remain to be investigated.

Does cognitive decline decrease health utility value in older adult patients with cancer?

AIM

Cognitive decline is common among older adults with cancer. The present study aimed to investigate the impact of cognitive decline on health utility value in older adults suffering from cancer.

METHODS

Consecutive patients aged 65 years or older with a primary diagnosis of malignant lymphoma or multiple myeloma were recruited. Patients were asked to complete the EuroQoL-5 (EQ-5D) scale to measure health utility and the Mini-Mental State Examination to assess cognitive decline. The potential impact of cognitive decline was investigated with univariate analysis. A multivariate regression analysis was conducted to control for potential confounding factors.

RESULTS

Complete data were obtained from 87 patients, 29% of whom had cognitive decline. The mean ± SE EQ-5D score for patients with cognitive decline was significantly lower than that for those without cognitive decline (0.67 ± 0.04 vs 0.79 ± 0.03, t = 2.38, P = 0.02). However, multiple regression analysis showed that cognitive decline was not significantly associated with EQ-5D scores. Female sex and lower performance scores (worse physical condition) were significantly associated with EQ-5D scores.

CONCLUSIONS

Cognitive decline may be involved in decreased health utility value in older adult patients with cancer. However, this effect does not seem to be independent, and the patient's physical condition may be a relevant confounding factor.

Identification of the predictors of cognitive impairment in patients with cancer in palliative care: a prospective longitudinal analysis

PURPOSE

Studies with neuropsychological assessments in patients with cancer are sparse, and the evidence is very limited regarding their status of cognitive function over time. This study aimed at assessing the prevalence and predictors of cognitive impairment in patients with cancer in palliative care.

METHODS

Prospective longitudinal investigation derived from the European Palliative Care Cancer Symptom study (2011-2013) including patients with cancer in palliative care, ≥18 years, and with at least one assessment post-inclusion. For cognitive assessment, a 4-item version of the Mini Mental State Examination was applied at inclusion and after 4 to 16 weeks. Logistic regression model with multiple imputations was applied.

RESULTS

The sample consisted of 1568 patients (50% male, mean age 65.5, 42% with 10-12 years schooling, mean Karnofsky Performance Status-KPS 68%). Longitudinal analysis of the patients with complete MMSE at both assessments (n = 801) showed that 64.5% were not impaired, 12.5% remained cognitively impaired, 11.4% developed impairment, and 11.6% improved. Those who improved cognitively also reported reduced pain intensity and increased appetite. The predictive model (n = 1351) showed that those with low KPS (OR = 1.6, 95% CI 1.0-2.5) most often developed cognitive impairment, while patients with breast cancer (OR = 0.4, 95% CI 0.2-0.7) had lower odds for impairment.

CONCLUSIONS

During palliative care, a substantial number of patients remained cognitively impaired or developed cognitive impairment; however, it is noteworthy that improvement was also observed. Physical performance and cancer type may predict cognitive impairment.

Fatigue in people with localized colorectal cancer who do and do not receive chemotherapy: a longitudinal prospective study

BACKGROUND

Fatigue is associated with cancer and chemotherapy and may be sustained. Here, we describe a prospective longitudinal study evaluating fatigue and putative mechanisms in people with colorectal cancer (CRC).

PATIENTS AND METHODS

People with localized CRC completed the Functional Assessment of Cancer Treatment-Fatigue (FACT-F) questionnaire at baseline (before chemotherapy, if given), 6, 12, and 24 months. Healthy controls (HCs) were assessed at the first three time points. Fatigue was defined by standardized FACT-F scores ≤68/100. Quality-of-life (QoL, assessed by the FACT-G questionnaire), affective, and cognitive symptoms were evaluated. Associations were sought between fatigue, baseline factors, and blood tests (including hemoglobin, cytokines, and sex hormones). Regression analyses, Fisher's exact tests, and Wilcoxon rank-sum tests assessed levels of fatigue at each time point and change in fatigue from baseline. A repeated-measures analysis investigated prognostic factors of fatigue across all time points.

RESULTS

A total of 289 subjects with localized CRC (173 received chemotherapy) and 72 HCs were assessed. More CRC patients had fatigue than HCs at baseline (52% versus 26%, P < 0.001). Fatigue was increased in the chemotherapy (CTh) group at 6 months [CTh+ 70% versus CTh- 31% (P < 0.001), HCs 22%] and remained more common at 12 [CTh+ 44% versus CTh- 31% (P = 0.079)] and 24 months [CTh+ 39% versus CTh- 24% (P = 0.047)]. There was no significant difference between those not receiving chemotherapy and HCs at follow-up assessments. Fatigue was associated with poor QoL, affective and cognitive symptoms, but not consistently with cytokine levels. Predictors for sustained fatigue were baseline fatigue, treatment group, cognitive and affective symptoms, poorer QoL, and comorbidities.

CONCLUSIONS

CRC patients have more fatigue than HCs at baseline. Fatigue peaks immediately after adjuvant chemotherapy, but remains common for 2 years in those who receive chemotherapy. Cognitive and affective symptoms, QoL, comorbidities, chemotherapy, and baseline fatigue predict for longer term fatigue.

Cytokine-mediated blood brain barrier disruption as a conduit for cancer/chemotherapy-associated neurotoxicity and cognitive dysfunction

Neurotoxicity is a common side effect of chemotherapy treatment, with unclear molecular mechanisms. Clinical studies suggest that the most frequent neurotoxic adverse events affect memory and learning, attention, concentration, processing speeds and executive function. Emerging preclinical research points toward direct cellular toxicity and induction of neuroinflammation as key drivers of neurotoxicity and subsequent cognitive impairment. Emerging data now show detectable levels of some chemotherapeutic agents within the CNS, indicating potential disruption of blood brain barrier integrity or transport mechanisms. Blood brain barrier disruption is a key aspect of many neurocognitive disorders, particularly those characterized by a proinflammatory state. Importantly, many proinflammatory mediators able to modulate the blood brain barrier are generated by tissues and organs that are targets for chemotherapy-associated toxicities. This review therefore aims to explore the hypothesis that peripherally derived inflammatory cytokines disrupt blood brain barrier permeability, thereby increasing direct access of chemotherapeutic agents into the CNS to facilitate neuroinflammation and central neurotoxicity.

A clinically relevant dose of cyclophosphamide chemotherapy impairs memory performance on the delayed spatial alternation task that is sustained over time as mice age

BACKGROUND

Cyclophosphamide chemotherapy is a mainstay of adjuvant breast cancer treatment. Unfortunately, this drug is associated with cognitive impairments in cancer patients that may accelerate cognitive aging. Memory is particularly affected in many patients. In order to better understand the precise cognitive impairments caused by this chemotherapy agent, we investigated a clinically relevant dose and administration paradigm on delayed spatial memory abilities in C57BL/6 mice. We utilized a delayed alternation paradigm similar to a delayed match to sample paradigm reported to be sensitive in human neurotoxicology research.

METHODS

A dose of 200mg/kg cyclophosphamide was administered intravenously (at weekly intervals) for 4 weeks to C57BL/6 mice starting at 6 ½ months of age. Memory was tested in mice using a reward-based delayed spatial alternation paradigm with delay values of 1.5, 3, 6.1, 12.4 and 25s presented randomly over 80 sessions (16 reinforcers per session), and testing began at the initiation of chemotherapy through 3 months.

RESULTS

At the longest delay, i.e., that requiring the greatest memory, mice treated with chemotherapy exhibited a significant decline over time in percent correct which leveled off compared to controls that continued to improve slightly.

CONCLUSIONS

Our clinically relevant model shows cyclophosphamide chemotherapy causes a slight decline in delayed spatial memories at the longest delay that is sustained over time as mice age.