Immunochemotherapy given earlier in the day linked to longer survival in people with advanced small cell lung cancer. Digest
The time of day at which cancer treatments are administered is often set by clinic logistics, yet the body operates on its own biological clock. A team in China examined whether the time of day of first-line immunochemotherapy for an advanced stage of small cell lung cancer is associated with treatment outcomes.
Researchers retrospectively analyzed records from 397 adults treated for an advanced stage of small cell lung cancer. All patients received a programmed death ligand 1 (PD-L1) blocking antibody, either atezolizumab or durvalumab, plus platinum chemotherapy. The median start time of each patient's first four cycles was then used to sort them into early or late groups, defined as treatment administered before or after 3:00 pm.
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Earlier treatments were linked to several better outcomes:
- Earlier treatment was tied to longer periods before the cancer worsened (progression-free survival). Patients treated before 3:00 pm had 7.6 months without progression compared with 5.8 months for later treatment. Statistical modeling showed this corresponded to about a 50% lower risk of progression during the study period.
- Patients treated before 3:00 pm lived a median of 18.4 months compared with 11.6 months for those treated later, corresponding to a 61% lower risk of death during the study period.
- About 82% of patients treated earlier in the day saw their tumors get smaller, compared with about 68% of those treated later.
- After accounting for key health factors to ensure the groups were comparable, the patterns still stayed the same or became even stronger.
PD-L1 is a protein tumors use to suppress T-cells through the PD-1 receptor. Research indicates that activity in this pathway and the presence of immune cells inside tumors vary across the day. Delivering PD-L1 blockade during a more favorable immune window may enhance benefit without altering drugs or doses.
Because the study relied on past records from a single center, included only a small number of people treated later in the day, and involved mostly men, it cannot show cause and effect, and its findings should be interpreted with caution. However, if future randomized trials confirm these results, treatment scheduling could become a practical lever for personalizing immunotherapy. In this clip, I share 10 science-backed strategies to reduce cancer risk.