Written by Chrystal Moulton, Staff Writer. Melatonin significantly improved cognitive function, depressive symptoms and sleep quality in breast cancer patients.
Cognitive impairment occurs in 23% of women with breast cancer receiving chemotherapy 1. Inflammatory response activated by chemotherapy or cancer maybe the cause of cognitive and behavioral changes 2. Limited evidence regarding a neuroprotective treatment against changes in key inflammatory biomarkers such as brain- derived neurotrophic factor (BDNF) and tropomyosin receptor kinase B (TRKB) makes it difficult to prevent neuroplastic degeneration caused by chemotherapy and cancer. Melatonin, which has demonstrated positive effects on sleep quality and depressive symptoms in breast cancer patients 3,4, has not been explored for its neuroprotective effect on cognitive function. Researchers in this study investigated possible neuroprotective effects of melatonin on cognitive function 5.
In a randomized double-blind placebo-controlled trial, 36 female patients with breast cancer were assigned to receive either 20 MG of oral melatonin daily or placebo for 10 days. Patients were advised to take their assigned treatment approximately one hour before bedtime. At baseline and at the end of the study, researchers assessed for demographic characteristics, quality of life, and cognitive tests which measure processing speed, episodic memory retention, lexical knowledge, and attention. Researchers also assessed for depressive symptoms and sleep quality at baseline and end of study. In order to assess changes in neuroplasticity, researchers evaluated serum levels brain- derived neuro trophic factor (BDNF) and tropomyosin receptor kinase B (TRKB) at baseline and end of study. Patients were instructed to take their assigned treatment three days prior to their first round of adjuvant chemotherapy and to continue taking it for seven days. On day 11, (8 days after chemotherapy), patients returned for their final evaluations. Primary outcome of this study was total time to complete Trail Making Test Part A&B [TMT A-B] (cognitive test measuring processing speed and cognitive flexibility). Secondary outcomes included results of other cognitive tests, sleep quality, and depressive symptoms.
Results of the Trail Making Test correlated to serum biomarker TRKB and BDNF showed that the change in time to complete Trail Making Test Part B was negatively correlated to serum TRKB levels at baseline (standardized beta = -0.19; t = – .68, P = 0.001). However, change in time to complete Trial Making Test Part A was negatively correlated to serum BDNF levels at baseline (standardized beta = -0.005, T = – 2.92, P = 0.007). Corresponding changes in depressive symptoms and sleep quality can be seen in Table 1.
Table 1. Changes in Serum inflammatory biomarkers, depressive symptom (BDI), & sleep quality (PSQI)| Placebo | Melatonin | ||||
| Baseline | End | Baseline | End | P-value | |
| BDI-I/II (mean) | 10.83 | 14.56 | 11.41 | 6.71 | P <0.001 |
| PSQI (mean) | 8.44 | 11.06 | 8.24 | 5.06 | P <0.001 |
| BDNF (mean) | 40.88 | 43.76 | 41.65 | 21.32 | P <0.001 |
| TRKB (mean) | 0.47 | 0.52 | 0.56 | 0.41 | P = 0.002 |
Researchers saw an improvement in sleep and depression symptoms at the end of the trial. Changes in TRKB serum levels were correlated with a greater reduction in depressive symptoms (standardized beta = – 9.31; T = – 2.13, P = 0.04). Changes in TRKB was also correlated with improvements in sleep quality scores (standardized beta = -4.50; T = -2.98, P = 0.006) [lower score indicates improvement]. Linear regression analysis showed that overall quality of life score for side effects were significantly improved in the melatonin group post-treatment (p<0.001). No significant changes were observed in quality of life for the placebo group pre to post treatment.
Overall findings show that melatonin use prior to adjuvant chemotherapy for breast cancer is effective in improving cognitive scores in breast cancer patients. Furthermore, depressive symptoms and sleep quality were inversely associated with changes in TRKB serum biomarker. No change, however, was found in cognitive tests for sustained attention and inhibitory control. Studies supported use of melatonin prior to adjuvant chemotherapy for neuroprotection in breast cancer patients. Further studies will be needed to elucidate the biological mechanisms that produced these effects.
Source: Palmer, Ana Claudia Souza, Maxciel Zortea, Andressa Souza, Vinicius Santos, Jorge Villanova Biazús, Iraci LS Torres, Felipe Fregni, and Wolnei Caumo. “Clinical impact of melatonin on breast cancer patients undergoing chemotherapy; effects on cognition, sleep and depressive symptoms: a randomized, double-blind, placebo-controlled trial.” PloS one 15, no. 4 (2020): e0231379.
© 2020 Palmer et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Posted May 17, 2021.
Chrystal Moulton BA, PMP, is a 2008 graduate of the University of Illinois at Chicago. She graduated with a bachelor’s in psychology with a focus on premedical studies and is a licensed project manager. She currently resides in Indianapolis, IN.
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- Palmer ACS, Zortea M, Souza A, et al. Clinical impact of melatonin on breast cancer patients undergoing chemotherapy; effects on cognition, sleep and depressive symptoms: A randomized, double-blind, placebo-controlled trial. PLoS One. 2020;15(4):e0231379.
