Adaptive Lung Radiation Therapy in the Era of Immunotherapy: A Single-Center Retrospective Study

Daniella Portal; Shou-En Lu; Huzaifa Piperdi; Salma K Jabbour; Meral Reyhan

doi:10.1016/j.adro.2023.101315

Adaptive Lung Radiation Therapy in the Era of Immunotherapy: A Single-Center Retrospective Study

Adv Radiat Oncol. 2023 Jul 10;9(1):101315. doi: 10.1016/j.adro.2023.101315. eCollection 2024 Jan.

Authors

Daniella Portal¹, Shou-En Lu², Huzaifa Piperdi³, Salma K Jabbour^{1

3}, Meral Reyhan^{1

3}

Affiliations

¹ Rutgers Robert Wood Johnson Medical School, Rutgers, The State of New Jersey University, Piscataway, New Jersey.
² Department of Biostatistics and Epidemiology, Rutgers School of Public Health, Rutgers, The State of New Jersey University, Piscataway, New Jersey.
³ Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey.

Abstract

Purpose: Treatment for locally advanced non-small cell lung cancer consists of concurrent chemoradiation followed by immunotherapy. Though this combination has been shown to have a benefit in both progression-free survival and overall survival, treatment is often limited by the development of pneumonitis. One way to mitigate toxicity is through adaptive radiation therapy, which does not currently have a standardized implementation in clinical practice.

Methods and materials: A single-center retrospective review of patients with locally advanced stage III or oligometastatic stage IV non-small cell lung cancer who were treated with chemoradiation with concurrent or subsequent immunotherapy from 2015 to 2020 was performed. Patients were stratified based on having 1 or more offline adapted plan. The aim of this study was to evaluate the association between dose-volume histogram values and common toxicities experienced during this treatment, including pneumonitis and esophagitis.

Results: Twenty-five patients were included in the final analysis: 10 with adapted plans (AP), and 15 with nonadapted plans (NAP). Mean age at onset was 74 years. The most common histology was adenocarcinoma (N = 13). Five patients experienced pneumonitis: 2 in AP and 3 in NAP. Mann-Whitney U test of gross tumor volume sizes between AP (346.2 ± 269.7 cm³) and NAP (153.1 ± 99.6 cm³) was significant (P = .019). Multiple linear regression analysis with adjustment for covariates of pneumonitis versus plan adaptation (P = .106) and esophagitis versus plan adaptation (P = .59) did not demonstrate a significant difference in toxicity between the adapted and nonadaptive patients.

Conclusions: Despite similar toxicities in both groups, the gross tumor volume size in the AP was more than double compared with NAP, suggesting that adaptive techniques provide a method for patients with larger target volumes to be treated without an observed difference in pneumonitis rates. These results suggest adaptive radiation therapy may have a role in mitigating toxicity experience from chemoradiation and immunotherapy and warrants further investigation.

Grants and funding

P30 CA072720/CA/NCI NIH HHS/United States