The Effect of Cancer Treatments on Telomere Length: A Systematic Review of the Literature.

Author: Gallicchio L1, Gadalla SM2, Murphy JD1, Simonds NI3
Affiliation: <sup>1</sup>Epidemiology and Genomics Research Program, Division of Cancer Control and Population Sciences, National Cancer Institute, Rockville. <sup>2</sup>Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville. <sup>3</sup>Scientific Consulting Group, Inc., Gaithersburg.
Conference/Journal: J Natl Cancer Inst.
Date published: 2018 Sep 28
Other: Special Notes: doi: 10.1093/jnci/djy189. [Epub ahead of print] , Word Count: 246


Background: It has been hypothesized that cancer treatments cause accelerated aging through a mechanism involving the shortening of telomeres. However, the effect of cancer treatments on telomere length is unclear.

Methods: We systematically reviewed the epidemiological evidence evaluating the associations between cancer treatment and changes in telomere length. Searches were performed in PubMed for the period of January 1966 through November 2016 using the following search strategy: telomere AND (cancer OR tumor OR carcinoma OR neoplasm) AND (survivor OR patient). Data were extracted and the quality of studies was assessed.

Results: A total of 25 studies were included in this review. Ten were solid cancer studies, 11 were hematological malignancy studies, and 4 included a mixed sample of both solid and hematological cancers. Three of the 10 solid tumor studies reported a statistically significant association between cancer treatment and telomere length shortening, and one reported longer telomere length after treatment. Among the hematological cancer studies, three showed statistically significant decreases in telomere length with treatment, and two showed elongation. When these studies were rated using quality criteria, most of the studies were judged to be of moderate quality.

Conclusions: The findings from this review indicate that the effect of cancer treatment on telomere length may differ by cancer type and treatment as well as other factors. Definitive conclusions cannot be made based on the published literature, because sample sizes tended to be small; treatments, cancer types, and biospecimens were heterogenous; and the length of follow-up times differed greatly.

PMID: 30272225 DOI: 10.1093/jnci/djy189