Integrating imaging findings in evaluating the post-chemotherapy brain

Abstract

Cognitive complaints following cancer and cancer therapy are common. Many studies have investigated the effects of chemotherapy on the brain. However, the mechanisms for the associated cognitive impairment are not well understood. Some studies have also included brain imaging to investigate potential neurological substrates of cognitive changes. This review examines recent neuroimaging studies on cancer- and chemotherapy-related cognitive dysfunction in non-central nervous system cancers and compares findings across imaging modalities. Grey matter volume reductions and decreases in white matter integrity are seen after exposure to adjuvant chemotherapy for breast cancer, and functional studies have illuminated both hypo- and hyperactivations in many of the same regions months to years following therapy. These comparisons can assist in further characterizing the dysfunction reported by patients and contribute to a better understanding of the mechanisms involved.

Default mode network as a potential biomarker of chemotherapy-related brain injury

“…Chemotherapy is often associated with persistent cognitive decline affecting an estimated 78% of patients with non-CNS cancer (Wefel and Schagen, 2012). Neuroimaging studies provide insight regarding the effects of chemotherapy on cognition by demonstrating subtle but diffuse brain injury [see reviews by: (de Ruiter and Schagen, 2013;Kaiser, et al, 2014;Koppelmans, et al, 2013;McDonald and Saykin, 2013;Pomykala, et al, 2013a;Scherling and Smith, 2013;Simo, et al, 2013)].…”

“…BCC-related cognitive dysfunction may represent a brain network disorder given the widespread brain alterations that are noted even decades after treatment has ended (Pomykala, et al, 2013a). The coordinated, dynamic brain network response that supports cognitive function depends critically on stable structural networks (Sporns, 2011).…”

Challenges in research on the neural basis of „chemobrain”

“…Structural and functional brain imaging studies have started to elucidate the neural correlates of chemotherapy-related cognitive decline in humans [21][22][23][24]. Examinations of cortical structure using magnetic resonance imaging (MRI) have demonstrated reductions of both gray and white matter volume when comparing chemotherapy-treated patients with either healthy controls [25] or untreated patients [26].…”

Chemotherapy-induced neurotoxicity in pediatric solid non-CNS tumor patients: An update on current state of research and recommended future directions

“…Similar to the existing neurocognitive studies, most imaging studies for solid tumor patients which investigate chemotherapy-induced neurotoxicity, were conducted for adult breast cancer patients [151][152][153]. They described both structural as well as functional neural changes.…”