Administering immunotherapy and chemotherapy in the morning is more effective at slowing lung cancer than doing so in the afternoon.

The effect of immunochemotherapy—the treatment that combines chemotherapy and immunotherapy—in patients with advanced lung cancer changes depending on whether it is administered in the morning or afternoon. In fact, it is usually more effective in the first part of the day. This is one of the main conclusions of a pioneering study published in the journal Nature Medicine, The study, which included up to 210 patients with advanced lung cancer, demonstrated that receiving treatment before 3 p.m. slows disease progression more effectively than administering it in the afternoon. Researchers emphasize that this simple adjustment to the infusion schedule represents an effective and cost-free strategy that could be immediately implemented in clinical practice to improve cancer outcomes. The answer to this treatment advance lies in circadian rhythms, which regulate the function and distribution of immune cells. Immunotherapy aims to activate or restore the body's natural immune response so that the body itself can fight tumor cells. It works by using drugs that boost CD8+ T lymphocytes—white blood cells that play a fundamental role in the body's defense against cancer—and enable them to directly identify and destroy malignant cells. When immunotherapy is administered in the morning, the number of active CD8+ T cells increases, and their depletion is reduced. However, according to the study, if the treatment is administered in the afternoon, these cells are more depleted. During the trial, which lasted approximately two years, patients were divided into two groups: the first received immunotherapy before 3 p.m., and the second, in the afternoon. Those who received treatment in the morning did not experience cancer progression for 11.3 months. In contrast, in the group treated in the afternoon, the period without progression was 5.7 months. That is, their resistance to lung cancer practically doubled. The median overall survival—an indicator that measures the total time patients live from the start of treatment until death—was 28 months in the initial group and 16.8 months in the second group. Therefore, the conclusion of the trial is that survival time also increases significantly if immunotherapies are administered in the morning. Pioneering study

Until now, several retrospective cancer studies have suggested that administering treatment first thing in the morning might be more effective. However, no controlled clinical trial had validated this. The study was led by researchers at Hunan Cancer Hospital in China, co-directed by Nong Yang and Yongchang Zhang. It is an international collaboration with the University of Geneva, Paris-Saclay University, and the Chinese University of Hong Kong. The authors note that further research is needed to link these results to long-term survival. A key limitation of the study is that the patient population was exclusively from China. However, it represents a step forward in cancer research, particularly by integrating the biological clock (i.e., circadian rhythms) as a key factor in modern oncology. This discovery could also radically transform the logistics of day units in hospitals worldwide.