Comparing Chemotherapy With Concurrent Proton Versus Photon Radiotherapy in NSCLC

Concurrent chemoradiotherapy (CCRT) followed by adjuvant durvalumab is standard of care for patients with unresectable stage III NSCLC. Results of a study that compared intensity-modulated proton therapy (IMPT) with intensity-modulated photon therapy (IMRT) and its impact on hematological toxicity and effect on durvalumab treatment were presented at the ESMO Congress 2023.

The researchers performed a retrospective analysis of 271 patients with stage III NSCLC who received CCRT between 06.16 and 12.22, staged with ¹⁸F-fluorodeoxyglucose positron emission tomography/CT and brain imaging. Among the 271 patients, 71 received IMPT and 200 received IMRT. All patients received platinum-based chemotherapy. The median patient age was 66 years, and 36% had a squamous NSCLC. A total of 41% had stage IIIA NSCLC, 89% had a World Health Organization (WHO) performance status (PS) of 0 or 1, 65% were PD-L1-positive, and 76% received q21 of chemotherapy (no differences between IMPT and IMRT).

Results showed the incidence of lymphopenia grade 3 (G3) was 66.7% and 47.0% in the IMRT and IMPT arms, respectively (OR, 2.2; 95% CI, 1.03-4.90; P=.032). Findings from a multivariable logistic model that included WHO PS, type and schedule of CT, age, and gross tumor volume showed that IMRT remained significantly associated with higher risk of lymphopenia G3 (adjusted OR [aOR], 2.6; 95% CI, 1.1-6.2; P=.029). The incidence of anemia G3 during CCRT in the IMRT and IMPT arms was 26.0% and 8.5%, respectively (aOR, 4.9; 95% CI, 1.9-12.6; P=.001).

The researchers concluded that “IMPT can reduce severe lymphopenia and anemia in patients with unresectable stage III NSCLC. Patients treated with IMPT have a better PS after CCRT and they are more likely to receive adjuvant durvalumab.”

Source: Cortiula F, Hendriks L, Wijsman R, et al. Chemotherapy with concurrent proton vs photon radiotherapy in stage III NSCLC: effects on hematological toxicity and immune therapy. Abstract of a poster presented at the ESMO Congress 2023; October 20-24, 2023; Madrid, Spain.