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Telomeres are the caps on chromosomes that shorten each time a cell divides. They are the oldest and best known measure of cellular ageing, and the one with the least to show for itself in cancer survivors so far: the measurements exist, the associations are inconsistent, and nothing follows from a result.
Telomere length is usually measured in leukocytes, which makes it a measure of how much the blood compartment has divided rather than of the body as a whole. In a nested case-control study within the Childhood Cancer Survivor Study, 46 radiation-exposed survivors who developed a thyroid subsequent malignant neoplasm were matched to 46 who did not. Cases had shorter median lymphocyte telomere length in three of four leukocyte subsets, were more likely to have natural killer cell telomere length below the 10th percentile (P = 0.01), and were 2.8 times more likely to have naive T-cell telomere length below the 10th percentile (95% CI 1.07 to 8.78).
Against that, in 1,413 long-term survivors of childhood cancer assessed with a full neuropsychological battery, mean leukocyte telomere length was not associated with neurocognitive function, while two epigenetic clocks were. The two findings are not contradictory, but together they show the limits of the measure: telomere length in blood picks up some of what treatment did to the haematopoietic compartment and little of what it did elsewhere.
No intervention has been shown to lengthen telomeres in people in a way that changes health, and products sold on that claim are selling a measurement, not an outcome. Telomerase is also the enzyme most cancers reactivate, which is a reason for caution about anything that promises to switch it on.
Telomeres shorten with each replication and with oxidative stress; below a threshold the cell arrests or dies. Cytotoxic therapy destroys dividing haematopoietic cells and forces the survivors to divide more to repopulate the marrow, so the blood compartment of a survivor has a replicative history longer than the calendar suggests.
Query for this technology: (TITLE:"telomere length" OR ABSTRACT:"telomere length" OR TITLE:"leukocyte telomere length" OR ABSTRACT:"leukocyte telomere length") AND ((cancer OR tumor OR tumour OR oncology OR carcinoma OR lymphoma OR leukemia OR leukaemia OR myeloma OR sarcoma OR melanoma OR glioma) OR survivor). Results are unfiltered search hits about Telomere length after treatment, not a curated reading list.
Shares Epigenetic age after cancer treatment, What actually works after treatment, Late effects and survivorship toxicity, Survivorship care and late-effects surveillance and the tags rejuvenation, survivorship, biological-ageing, biomarker.
Shares Clonal haematopoiesis after cancer treatment, Epigenetic age after cancer treatment, What actually works after treatment, Late effects and survivorship toxicity and the tags rejuvenation, survivorship, biological-ageing.
Shares What actually works after treatment, Late effects and survivorship toxicity, Survivorship care and late-effects surveillance, Survivorship and late effects are neglected and the tags rejuvenation, survivorship.
Shares What actually works after treatment, Late effects and survivorship toxicity, Survivorship care and late-effects surveillance, Survivorship and late effects are neglected and the tags rejuvenation, survivorship.
Shares What actually works after treatment, Late effects and survivorship toxicity, Survivorship care and late-effects surveillance, Survivorship and late effects are neglected and the tags rejuvenation, survivorship.
Shares What actually works after treatment, Late effects and survivorship toxicity, Survivorship care and late-effects surveillance, Survivorship and late effects are neglected and the tags rejuvenation, survivorship.
Shares What actually works after treatment, Late effects and survivorship toxicity, Survivorship care and late-effects surveillance and the tags rejuvenation, survivorship.
Shares What actually works after treatment, Late effects and survivorship toxicity, Survivorship and late effects are neglected and the tags rejuvenation, survivorship.