Thymic Radiation Linked to Worse Outcomes in Patients With NSCLC

THURSDAY, Aug. 27, 2026 (HealthDay News) — For patients with non-small cell lung cancer (NSCLC), thymic radiation exposure is independently associated with increased risks for distant metastasis, according to a study published online Aug. 25 in the Annals of Oncology.

Vasco Prudente, from Harvard Medical School in Boston, and colleagues conducted a multicohort analysis of 1,107 patients with NSCLC, including the phase 3 RTOG-0617 trial (460 patients) and two real-world cohorts of patients treated with chemoradiotherapy alone (HARVARD-CRT; 422 patients) or in combination with consolidation immunotherapy (HARVARD-DURVA; 225 patients). Thymic function was quantified using a deep learning system. Thymic radiation exposure was measured using mean thymic dose (MTD).

The researchers found that after confounding adjustments, incidental thymic irradiation was associated with an increased risk for distant metastasis. A 1-Gy increase in MTD was associated with a 1.57 to 4.21 percent increased risk for distant metastasis (adjusted hazard ratios, 1.29, 1.33, and 1.95 for RTOG-0617, HARVARD-CRT, and HARVARD-DURVA, respectively). Patients with preserved thymic health (TH) before radiotherapy seemed to have a particularly greater risk; in patients with impaired TH, no associations emerged. Dose-dependent declines in TH and lower circulating lymphocyte counts were demonstrated in one-year follow-up imaging.

“The patients who benefit most from immunotherapy may also be the ones who benefit most from protecting the thymus during radiation treatment,” co-senior author Raymond H. Mak, M.D., from Mass General Brigham Cancer Institute, said in a statement. “[These studies] reinforce the broader concept that successful cancer treatment is not only about eliminating the tumor, but also about preserving the patient”s immune system.”

Several authors disclosed ties to the biopharmaceutical industry.

Abstract/Full Text