Interventions promoting cognitive function in patients experiencing cancer related cognitive impairment: A systematic review

OBJECTIVE

To examine the effect of interventions used to enhance cognitive function in patients experiencing cancer-related cognitive impairment.

METHODS

Studies including adults with a non-metastatic cancer who have received chemotherapy as part of their treatment and who have undergone interventions targeting cancer-related cognitive impairment were included. Studies involving patients with metastatic cancer and pre-existing cognitive deficits were excluded. Academic Search Complete, CINAHL Plus with full text, MEDLINE, Education Full Text, PsycARTICLES, PsycINFO, and ERIC were searched for studies published between January 2011 and September 2022. Data extraction and quality appraisal were conducted by two authors and cross-checked by the review team. Quality appraisal was conducted using 12 items from the Mixed Methods Appraisal Tool. Findings were presented narratively without meta-analysis.

RESULTS

Thirty-one studies were included. Interventions were categorised as integrative/complementary, cognitive behavioural therapy and compensatory strategies, exercise, psychoeducational/psychosocial, brain-training, and pharmacological. Over 100 instruments were identified, including the Functional Assessment of Cancer Therapy-Cognitive, Trail Making Tests-A and B, and instruments measuring secondary outcomes, including depression. Instruments often measured attention and concentration, language, memory, executive function, and/or patient-reported outcomes. Improvements were reported, with most studies measuring some or various aspects of cognitive functioning and very few studies measuring all domains of cognitive functioning, making it difficult to draw definitive conclusions about effectiveness.

CONCLUSIONS

Various interventions are available to treat cancer-related cognitive impairment. Outcome measurement was inconsistent and future research should prioritise using standardised measures. Current evidence, whilst not being definitive, suggests that certain interventions show greater promise than others, including cognitive behavioural therapy and brain training.

Intravenous iron versus oral iron versus no iron with or without erythropoiesis- stimulating agents (ESA) for cancer patients with anaemia: a systematic review and network meta-analysis

BACKGROUND

Anaemia is common among cancer patients and they may require red blood cell transfusions. Erythropoiesis-stimulating agents (ESAs) and iron might help in reducing the need for red blood cell transfusions. However, it remains unclear whether the combination of both drugs is preferable compared to using one drug.

OBJECTIVES

To systematically review the effect of intravenous iron, oral iron or no iron in combination with or without ESAs to prevent or alleviate anaemia in cancer patients and to generate treatment rankings using network meta-analyses (NMAs).

SEARCH METHODS

We identified studies by searching bibliographic databases (CENTRAL, MEDLINE, Embase; until June 2021). We also searched various registries, conference proceedings and reference lists of identified trials.

SELECTION CRITERIA

We included randomised controlled trials comparing intravenous, oral or no iron, with or without ESAs for the prevention or alleviation of anaemia resulting from chemotherapy, radiotherapy, combination therapy or the underlying malignancy in cancer patients.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed risk of bias. Outcomes were on-study mortality, number of patients receiving red blood cell transfusions, number of red blood cell units, haematological response, overall mortality and adverse events. We conducted NMAs and generated treatment rankings. We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

Ninety-six trials (25,157 participants) fulfilled our inclusion criteria; 62 trials (24,603 participants) could be considered in the NMA (12 different treatment options). Here we present the comparisons of ESA with or without iron and iron alone versus no treatment. Further results and subgroup analyses are described in the full text. On-study mortality We estimated that 92 of 1000 participants without treatment for anaemia died up to 30 days after the active study period. Evidence from NMA (55 trials; 15,074 participants) suggests that treatment with ESA and intravenous iron (12 of 1000; risk ratio (RR) 0.13, 95% confidence interval (CI) 0.01 to 2.29; low certainty) or oral iron (34 of 1000; RR 0.37, 95% CI 0.01 to 27.38; low certainty) may decrease or increase and ESA alone (103 of 1000; RR 1.12, 95% CI 0.92 to 1.35; moderate certainty) probably slightly increases on-study mortality. Additionally, treatment with intravenous iron alone (271 of 1000; RR 2.95, 95% CI 0.71 to 12.34; low certainty) may increase and oral iron alone (24 of 1000; RR 0.26, 95% CI 0.00 to 19.73; low certainty) may increase or decrease on-study mortality. Haematological response We estimated that 90 of 1000 participants without treatment for anaemia had a haematological response. Evidence from NMA (31 trials; 6985 participants) suggests that treatment with ESA and intravenous iron (604 of 1000; RR 6.71, 95% CI 4.93 to 9.14; moderate certainty), ESA and oral iron (527 of 1000; RR 5.85, 95% CI 4.06 to 8.42; moderate certainty), and ESA alone (467 of 1000; RR 5.19, 95% CI 4.02 to 6.71; moderate certainty) probably increases haematological response. Additionally, treatment with oral iron alone may increase haematological response (153 of 1000; RR 1.70, 95% CI 0.69 to 4.20; low certainty). Red blood cell transfusions We estimated that 360 of 1000 participants without treatment for anaemia needed at least one transfusion. Evidence from NMA (69 trials; 18,684 participants) suggests that treatment with ESA and intravenous iron (158 of 1000; RR 0.44, 95% CI 0.31 to 0.63; moderate certainty), ESA and oral iron (144 of 1000; RR 0.40, 95% CI 0.24 to 0.66; moderate certainty) and ESA alone (212 of 1000; RR 0.59, 95% CI 0.51 to 0.69; moderate certainty) probably decreases the need for transfusions. Additionally, treatment with intravenous iron alone (268 of 1000; RR 0.74, 95% CI 0.43 to 1.28; low certainty) and with oral iron alone (333 of 1000; RR 0.92, 95% CI 0.54 to 1.57; low certainty) may decrease or increase the need for transfusions. Overall mortality We estimated that 347 of 1000 participants without treatment for anaemia died overall. Low-certainty evidence from NMA (71 trials; 21,576 participants) suggests that treatment with ESA and intravenous iron (507 of 1000; RR 1.46, 95% CI 0.87 to 2.43) or oral iron (482 of 1000; RR 1.39, 95% CI 0.60 to 3.22) and intravenous iron alone (521 of 1000; RR 1.50, 95% CI 0.63 to 3.56) or oral iron alone (534 of 1000; RR 1.54, 95% CI 0.66 to 3.56) may decrease or increase overall mortality. Treatment with ESA alone may lead to little or no difference in overall mortality (357 of 1000; RR 1.03, 95% CI 0.97 to 1.10; low certainty). Thromboembolic events We estimated that 36 of 1000 participants without treatment for anaemia developed thromboembolic events. Evidence from NMA (50 trials; 15,408 participants) suggests that treatment with ESA and intravenous iron (66 of 1000; RR 1.82, 95% CI 0.98 to 3.41; moderate certainty) probably slightly increases and with ESA alone (66 of 1000; RR 1.82, 95% CI 1.34 to 2.47; high certainty) slightly increases the number of thromboembolic events. None of the trials reported results on the other comparisons. Thrombocytopenia or haemorrhage We estimated that 76 of 1000 participants without treatment for anaemia developed thrombocytopenia/haemorrhage. Evidence from NMA (13 trials, 2744 participants) suggests that treatment with ESA alone probably leads to little or no difference in thrombocytopenia/haemorrhage (76 of 1000; RR 1.00, 95% CI 0.67 to 1.48; moderate certainty). None of the trials reported results on other comparisons. Hypertension We estimated that 10 of 1000 participants without treatment for anaemia developed hypertension. Evidence from NMA (24 trials; 8383 participants) suggests that treatment with ESA alone probably increases the number of hypertensions (29 of 1000; RR 2.93, 95% CI 1.19 to 7.25; moderate certainty). None of the trials reported results on the other comparisons.

AUTHORS' CONCLUSIONS

When considering ESAs with iron as prevention for anaemia, one has to balance between efficacy and safety. Results suggest that treatment with ESA and iron probably decreases number of blood transfusions, but may increase mortality and the number of thromboembolic events. For most outcomes the different comparisons within the network were not fully connected, so ranking of all treatments together was not possible. More head-to-head comparisons including all evaluated treatment combinations are needed to fill the gaps and prove results of this review.