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ePoster Display

1175P - Predictors of pneumonitis in locally advanced non-small cell lung cancer patients treated on the Pacific regimen


16 Sep 2021


ePoster Display


Robert Gao


Annals of Oncology (2021) 32 (suppl_5): S939-S948. 10.1016/annonc/annonc728


R.W. Gao1, P. Prodduturvar2, C.N. Day3, W.S. Harmsen3, K.R. Olivier1, K.W. Merrell1, Y.I. Garces1, S. James1, T.K. McKone1, L. Ng1, R.S. Smith1, A. Stockham1, Z. Wilson1, J.R. Molina2, K. Leventakos2, A. Dimou2, A.S. Mansfield2, A.C. Amundson1, D. Owen1

Author affiliations

  • 1 Radiation Oncology, Mayo Clinic, 55905 - ROCHESTER/US
  • 2 Medical Oncology, Mayo Clinic, 55905 - ROCHESTER/US
  • 3 Biostatistics & Informatics, Mayo Clinic, 55905 - ROCHESTER/US

Abstract 1175P


Treatment-related pneumonitis is a significant concern in locally advanced non-small cell lung cancer (NSCLC) patients undergoing definitive chemoradiation (CRT). The incidence and predictors of pneumonitis in the era of consolidative durvalumab have yet to be fully elucidated. In this large, single institution, retrospective analysis, we analyze factors associated with grade 2+ pneumonitis in NSCLC patients treated on the Pacific regimen.


We identified all patients treated at our institution with definitive CRT followed by consolidative durvalumab from 2018 to 2021. Those with <3 months of follow-up were excluded. Clinical documentation and imaging were used to determine grade 2+ pneumonitis events, which required: 1) pulmonary symptoms requiring prolonged steroid taper, oxygen, and/or admission; and 2) radiographic findings consistent with pneumonitis. Cox proportional hazards regression models were applied to determine association between variables and pneumonitis.


One-hundred fifty patients met inclusion. Median number of durvalumab cycles received was 12. Most patients received standard dose durvalumab every 2 weeks and 17 (11.3%) received high dose (1500 mg) durvalumab every 4 weeks for at least one cycle. At a median follow-up of 15 months, 36 pneumonitis events occurred with a 1-year cumulative incidence of 25.7% (95% CI: 19.2-34.2). Grade 3+ and 5 pneumonitis occurred in 11 and 2 patients, respectively. Univariate and multivariate predictors of pneumonitis are listed in the table. Age, stage, prior radiation, total lung V20Gy, proton therapy, high dose durvalumab, and lymphocyte count were not predictive. Kaplan-Meier estimates of overall survival at 1 and 3 years were 88.7% and 55.5%, respectively. Table: 1175P

Predictors of pneumonitis V5Gy (%). Percentage of volume receiving at least 5 Gy. All p-values <0.05

Univariate HR (95% CI)
Durvalumab cycles 0.92 (0.87-0.96)
Total lung
Volume 0.68 (0.49-0.96)
Mean dose 2.66 (1.16-6.12)
Ipsilateral lung
Volume 0.51 (0.28-0.94)
Mean dose 1.71 (1.09-2.71)
V5Gy (%) 1.24 (1.03-1.50)
V10Gy (%) 1.26 (1.04-1.52)
V10Gy (cc) 9.85 (1.44-67.42)
V20Gy (%) 1.28 (1.02-1.60)
V40Gy (%) 1.30 (1.02-1.67)
Contralateral lung
Volume 0.52 (0.28-0.97)
Mean dose 2.42 (1.13-5.19)
V40Gy (%) 2.34 (1.28-4.28)
Multivariate HR (95% CI)
Durvalumab cycles 0.92 (0.88-0.97)
Contralateral lung mean dose 4.75 (1.09-20.68)


We report a risk of pneumonitis higher than that seen on RTOG 0617 and comparable to the Pacific study. Multiple lung dosimetric factors were found to be predictive of grade 2+ pneumonitis. Larger lung volume was protective.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.


Has not received any funding.


All authors have declared no conflicts of interest.

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