Timing of Immunotherapy Linked to Improved Cancer Survival in Multiple Studies

Recent research has examined whether the time of day when immunotherapy is administered affects treatment outcomes for cancer patients. Multiple studies have investigated this question across different cancer types, focusing on the potential benefits of morning or early afternoon treatment sessions.

A study published in December 2025 in the journal CANCER analyzed patients with extensive-stage small cell lung cancer who received immunochemotherapy. The findings indicated that those treated before 3:00 pm experienced longer periods without disease progression and higher overall survival rates compared to those who received treatment later in the day.

In this study, which included 397 patients treated between May 2019 and October 2023 at a hospital in China, the group receiving immunotherapy before 3:00 pm had a 52% lower risk of cancer progression and a 63% lower risk of death after adjusting for other factors. These results were also reported by HealthDay, which summarized the same hazard reductions for early-day treatment.

Additional research has explored similar timing effects in other cancers. A meta-analysis published in ESMO Open in February 2024 combined data from 13 studies and 1,663 patients with metastatic cancers, including non-small-cell lung cancer. This analysis found that earlier administration of immune checkpoint inhibitors was linked to about a 50% reduction in the risk of progression and death compared to later dosing.

What the numbers show

• 397 patients with small cell lung cancer studied between May 2019 and October 2023
• 52% lower risk of progression and 63% lower risk of death for early immunotherapy
• Meta-analysis included 1,663 patients from 13 studies across cancer types
• Morning nivolumab dosing in NSCLC: 11.3 vs 3.1 months progression-free survival
• Renal cell carcinoma: ≥20% of infusions before noon linked to improved outcomes

A retrospective cohort study focused on 95 patients with metastatic non-small-cell lung cancer who received nivolumab. Patients treated in the morning, with median dosing times between approximately 9:27 am and 12:54 pm, had a median progression-free survival of 11.3 months, compared to 3.1 months for those treated in the afternoon. Median overall survival was 34.2 months for morning dosing and 9.6 months for afternoon dosing, with hazard ratios indicating lower risks for progression and death in the morning group.

Meta-analyses have also evaluated timing across a range of cancers, such as lung, renal, melanoma, urothelial, and esophageal cancers. These analyses found that early-day infusions of immune checkpoint inhibitors were associated with longer overall and progression-free survival compared to later infusions.

In metastatic renal cell carcinoma, a multicenter cohort analysis showed that patients who received at least 20% of their immunotherapy infusions before noon had improved progression-free survival and overall survival, with hazard ratios of 0.70 and 0.57, respectively, after adjusting for multiple variables.

These studies support the concept of chronotherapy, which involves aligning treatment timing with the body's circadian rhythms to potentially enhance the effectiveness of immunotherapy. Observed timing effects are consistent with known patterns of immune cell function regulated by circadian cycles, but further randomized trials are needed to determine causality and inform clinical guidelines.

* This article is based on publicly available information at the time of writing.