University of Leicester | November 2018 | Use genetic data to predict the best time of day to give radiotherapy to breast cancer patients, say Researchers
Scientists from the University of Leicester followed two independent cohorts of patients with breast cancer being treated with radiotherapy (P equal to 879); where the researchers found that patients with variations of two genes were more likely to experience side effects if they received radiotherapy in the morning.
The researchers explain that this is due to their circadian rhythms, with radiotherapy treatment in the morning causing worse acute toxicity for these patients. They suggest that in future treatment it may be possible to reduce toxicity associated with breast cancer radiotherapy by identifying gene variants that affect circadian rhythm and tailoring treatment for appropriate morning or afternoon radiotherapy.
Professor Paul Symonds, a consultant oncologist at Leicester’s Hospitals and professor of clinical oncology at the University of Leicester said: “Our study found that some patients with a particular genetic profile are more at risk of side effects if given radiotherapy in the morning. This happens because the skin of these particular patients divides earlier in the day than others and dividing cells are more easily damaged by X-rays. This could allow an easy way to personalise treatment just by recommending what time of day a patient should be treated.”
The study was part-funded by the Breast Cancer Now charity and supported by funding from the European Union Seventh Framework Programme for research, technological development and demonstration (Source: University of Leicester).
Read the full article from the University of Leicester
Read and download the article Genetic Variants Predict Optimal Timing of Radiotherapy to Reduce Side-effects in Breast Cancer Patients from Clinical Oncology
Johnson, K., Chang-Claude, J., Critchley, A. M., Kyriacou, C., Lavers, S., Rattay, T., … & Talbot, C. J. (2018). Genetic variants predict optimal timing of radiotherapy to reduce side-effects in breast cancer patients. Clinical Oncology. https://doi.org/10.1016/j.clon.2018.10.001
Radiotherapy is an important treatment for many types of cancer, but a minority of patients suffer long-term side-effects of treatment. Multiple lines of evidence suggest a role for circadian rhythm in the development of radiotherapy late side-effects.
Materials and methods
We carried out a study to examine the effect of radiotherapy timing in two breast cancer patient cohorts. The retrospective LeND cohort comprised 535 patients scored for late effects using the Late Effects of Normal Tissue-Subjective Objective Management Analytical (LENT-SOMA) scale. Acute effects were assessed prospectively in 343 patients from the REQUITE study using the CTCAE v4 scales. Genotyping was carried out for candidate circadian rhythm variants.
In the LeND cohort, patients who had radiotherapy in the morning had a significantly increased incidence of late toxicity in univariate (P equal to 0.03) and multivariate analysis (P equal to 0.01). Acute effects in the REQUITE group were also significantly increased in univariate analysis after morning treatment (P equal to 0.03) but not on multivariate analysis.
Our results suggest that it may be possible to reduce toxicity associated with breast cancer radiotherapy by identifying gene variants that affect circadian rhythm and scheduling for appropriate morning or afternoon radiotherapy.
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