Pembrolizumab is a cancer drug that boosts the immune system, and when used with chemotherapy and radiation therapy, it can improve survival in patients with non-small cell lung cancer. However, it is still unclear how long the patients with non–small cell lung cancer should continue taking pembrolizumab after completing chemotherapy and radiation therapy. While clinical trials exist, patients in everyday clinical practice may have different outcomes because of side effects, cancer progression, personal preferences, access to care, and doctors’ treatment decisions.

The researchers conducted this study to evaluate how long patients lived and how often they used healthcare services while taking pembrolizumab. They retrieved data from the U.S. Collaborative Network called TriNetX, a de-identified electronic health record database covering multiple healthcare organizations.

On January 27, 2026, the researchers identified adult patients and divided them into two groups: 914 patients in the long-term pembrolizumab exposure group and 471 patients in the short-term group. After matching patients with similar characteristics, the final cohort included 899 patients in the long-term group and 458 in the short-term group. The long-term group received pembrolizumab for approximately 9–14 months, while the short-term group received it for up to 6 months. All patients had at least one year of follow-up, and chemoradiation was completed within three months before or at the start of treatment.

The researchers found that the long-term exposure group had a lower risk of death compared with the short-term group. There were 166 deaths among 448 patients (37.1%) in the long-term group and 207 deaths among 446 patients (46.4%) in the short-term group. On average, patients in the long-term group lived much longer (1505 days compared with 791 days). Use of healthcare services during treatment was similar between the two groups, with no significant difference observed.

These findings suggest that longer treatment with pembrolizumab is associated with improved survival in patients with non–small cell lung cancer treated with chemoradiation. It may reduce mortality and extend survival compared with shorter treatment duration, while maintaining similar healthcare utilization.

However, pembrolizumab cannot be assumed to benefit all patients equally, as outcomes may be influenced by differences in the cancer itself, response to therapy, treatment tolerance, patient frailty, clinician decision-making, access to care, and follow-up patterns. Another limitation is a survival-related bias, where patients in the long-term group had to survive long enough to receive additional treatment, which may make that group appear to have better outcomes. A further limitation is that other patient characteristics that were not fully accounted for may have affected both treatment duration and survival.

Reference

Homeniuk A, Syed A, Atrash A. Survival outcomes associated with prolonged pembrolizumab after definitive chemoradiation for non–small cell lung cancer. Clin Oncol (R Coll Radiol). Published online 2026. doi:10.1016/j.clon.2026.104227