Global and focal white matter integrity in breast cancer survivors 20 years after adjuvant chemotherapy

Hum Brain Mapp. 2014 Mar;35(3):889-99. doi: 10.1002/hbm.22221. Epub 2012 Dec 20.

Abstract

Objectives: To date, only four small studies have investigated the effects of adjuvant chemotherapy for breast cancer on the microstructure of cerebral white matter with magnetic resonance imaging (MRI). These studies, which were conducted shortly up to 10 years post-treatment, showed that chemotherapy is associated with focal loss of microstructural white matter integrity. We investigated the long-term effect of chemotherapy on white matter microstructural integrity by comparing the brains of chemotherapy-exposed breast cancer survivors to those of a population-based sample of women without a history of cancer.

Experimental design: Diffusion tensor imaging (DTI) MRI (1.5 T) was performed in 187 CMF (cyclophosphamide, methotrexate, and 5-flourouracil) chemotherapy-exposed breast cancer survivors, mean age 64.2 (sd = 6.5) years, who had been diagnosed with cancer on average 21.2 (sd = 4.4) years before, and 374 age-matched cancer-free reference subjects from a population-based cohort study. Outcome measures were whole-brain microstructural integrity as measured by fractional anisotropy and mean/axial/radial diffusivity and focal white matter integrity, which was analyzed with tract-based spatial statistics. All analyses were adjusted for age, cardiovascular risk factors, education, and symptoms of depression.

Principal observations: No significant group differences were observed in white matter integrity. However, within the breast cancer survivors, time since treatment was inversely associated with lower global and focal white matter integrity.

Conclusions: This cross-sectional study suggests that among chemotherapy-exposed breast cancer survivors white matter microstructural integrity deteriorates with accumulating time since treatment. This warrants further investigation.

Keywords: adjuvant; axons; brain; breast neoplasms; chemotherapy; diffusion tensor imaging; magnetic resonance imaging; time.

MeSH terms

  • Aged
  • Antineoplastic Agents / adverse effects*
  • Antineoplastic Combined Chemotherapy Protocols / adverse effects
  • Brain / drug effects
  • Brain / pathology*
  • Breast Neoplasms / drug therapy*
  • Chemotherapy, Adjuvant / adverse effects
  • Cross-Sectional Studies
  • Cyclophosphamide / administration & dosage
  • Cyclophosphamide / adverse effects
  • Diffusion Tensor Imaging / instrumentation
  • Diffusion Tensor Imaging / methods*
  • Female
  • Fluorouracil / administration & dosage
  • Fluorouracil / adverse effects
  • Humans
  • Leukoencephalopathies / chemically induced
  • Leukoencephalopathies / pathology*
  • Methotrexate / administration & dosage
  • Methotrexate / adverse effects
  • Middle Aged
  • Survivors
  • Time Factors

Substances

  • Antineoplastic Agents
  • Cyclophosphamide
  • Fluorouracil
  • Methotrexate