Benefit of radiotherapy for nasopharyngeal carcinoma may vary by time of day
Key takeaways:
- Patients with nasopharyngeal cancer who received morning radiotherapy survived longer than those treated later in the day.
- Researchers observed no difference in treatment-related adverse effects based on timing.
Patients with nasopharyngeal carcinoma who received radiotherapy in the morning survived longer than those who underwent radiotherapy later in the day, according to study results.
Chronoradiobiology — the study of how circadian rhythms affect the body’s response to radiation — has become an area of increased research interest.
“Although there have been previous investigations into the chronomodulation of cancer treatments, such as cytotoxic chemotherapy and immune checkpoint inhibitors, there remains a scarcity of studies examining the influence of radiation chronotherapy on prognosis,” Ying Li, MD, PhD, of the Clinical Oncology School of Fujian Medical University and Fujian Cancer Hospital, China, and colleagues wrote.
Li and colleagues conducted their study to assess whether radiation chronotherapy affected efficacy or toxicity for patients with nasopharyngeal carcinoma.
The study included 1,040 patients with nonmetastatic nasopharyngeal carcinoma who received intensity-modulated radiotherapy at Fujian Cancer Hospital between January 2017 and December 2019.
Researchers placed patients into one of three groups depending on the time of day that they received radiation treatment: 571 received morning radiotherapy (6 a.m. to 11:59 a.m.), 269 patients received afternoon radiotherapy (noon to 5:59 p.m.) and 200 patients received night radiotherapy (6 p.m. to midnight).
Data from the unmatched cohort showed a statistically significant OS improvement among patients who received morning radiotherapy compared with those treated in the afternoon (HR = 0.6; 95% CI, 0.4-0.91).
During propensity score matching analysis to account for selection bias, patients who underwent afternoon radiotherapy (HR = 5.88; 95% CI, 2.55-13.58) and night radiotherapy (HR = 4.81; 95% CI, 1.91-12.11) had shorter OS than patients who received morning radiotherapy.
Investigators observed no significant difference in acute treatment-related adverse effects based on treatment timing.
Researchers acknowledged study limitations, including the study’s retrospective design, single-institution setting and limited sample size.
“The results support timing radiotherapy for specific times of the day (morning radiotherapy) could be beneficial in patients with nasopharyngeal carcinoma,” Li and colleagues wrote. “Subsequent studies are essential for further characterizing and optimizing radiation therapeutic strategies, and appropriately designed clinical trials are indispensable for confirming the validity of our findings.”
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