Nearly 372,500 people in France underwent chemotherapy treatment in 2022, according to the National Cancer Institute (INCa). Researchers are now investigating whether the timing of chemotherapy and immunotherapy administration can significantly impact patient outcomes, with a recent study suggesting a substantial benefit for those treated before 3 p.m.
The study, conducted by researchers at the University of Paris-Saclay, followed 210 patients battling lung cancer for 29 months. Participants were divided into two groups: one receiving treatment before 3 p.m., and the other after. The results revealed a striking difference in survival rates. Patients treated in the morning lived an average of 28 months, compared to just 17 months for those treated in the afternoon – a disparity researchers described as “absolutely enormous.”
The potential explanation centers on the behavior of T lymphocytes, a type of white blood cell crucial for eliminating cancer cells. Researchers hypothesize that these lymphocytes are naturally more concentrated around tumors in the morning, making them more readily available to attack when chemotherapy and immunotherapy are administered. Conversely, they believe these immune cells become more dispersed throughout the body in the afternoon, potentially reducing treatment efficacy.
“We are almost multiplying the patient’s life expectancy by two,” researchers stated, according to reporting on the study. Further research is planned to validate these findings and explore individual variations. Scientists are particularly interested in determining whether a patient’s “chronotype” – whether they are a morning person or a night owl – influences the optimal timing of treatment. The question of whether the lymphocytes of those with different chronotypes function at different times is a key area of investigation.
The findings align with a broader understanding of the interplay between cancer treatment and the body’s natural rhythms. The French National Cancer Institute notes that various drug treatments, including chemotherapy, targeted therapies, and immunotherapies, are used to treat lung cancer, acting systemically throughout the body to reach cancer cells regardless of location. The Institut Curie highlights the increasing use of chemotherapy and immunotherapy before surgery, a technique shown to reduce the risk of relapse by 40% and improve survival rates.
The study’s results are prompting discussion about the potential for personalized treatment schedules, tailored to individual patient biology and circadian rhythms. However, researchers caution that more studies are needed to confirm the initial findings and establish clear guidelines for clinical practice. The next steps involve larger-scale trials and a deeper investigation into the mechanisms driving the observed differences in treatment response.
