Lung Cancer

PV QA 4 - Poster Viewing Q&A 4

TU_25_3564 - Influence of Dexamethasone Premedication on Acute Lung Toxicity in Lung SBRT

Tuesday, October 23
2:45 PM - 4:15 PM
Location: Innovation Hub, Exhibit Hall 3

Influence of Dexamethasone Premedication on Acute Lung Toxicity in Lung SBRT
F. Alite Jr1, M. P. Shaikh2, M. J. Greenberg1, D. Christie1, R. A. Rostock1, U. Malik1, and A. Mahadevan1; 1Geisinger Cancer Institute, Danville, PA, 2West Virginia University, Morgantown, WV

Purpose/Objective(s): The landmark RTOG 0236 phase II trial of Lung SBRT in medically inoperable NSCLC utilized corticosteroid premedication in patients treated with 60Gy in 3 fractions. Patterns of care have been mixed as to whether premedication adds benefit in terms of improved lung toxicity and treatment tolerance as dose/fractionation schedules have evolved to 5-8 fractions in lung SBRT.

Materials/Methods: We evaluated patients in a prospectively collected database treated for NSCLC from 2014-2017, with definitive thoracic SBRT (BED10≥100) at a single institution. Pretreatment clinicopathologic characteristics, including ECOG performance status, PFT parameters of FEV1, DLCO were collected. Treatment and dosimetric characteristics were collected and patients were scored as to whether dexamethasone was prescribed and utilized with each fraction. Toxicity was graded on multiple domains including lung as during and 30 days after completion of treatment in accordance with RTOG, performed using Common Terminology Criteria for Adverse Events Version 4. Hospitalization for acute exacerbation of COPD during or within 30 days after completion of treatment was also considered in analysis. Acute lung toxicity was defined as Grade 2 or higher lung toxicity or pneumonitis or admission during or within 30 days of treatment completion. Univariate analysis performed with Fisher exact test for categorical variables and two tailed Student t test for continuous. Multivariate analysis was performed with Cox proportional hazards model, to adjust for age, pre-treatment DLCO, ECOG, tumor size, central versus peripheral location, biological effective dose.

Results: 86 patients met inclusion criteria and were treated with thoracic SBRT with 54Gy-60Gy in 3-5 fractions, with the majority (70%) receiving 5 fractions. 45 patients (52%) received 4mg dexamethasone premedication prior to each fraction of SBRT, 41 patients (48%) were treated without dexamethasone premedication. Overall acute lung toxicity was low in both groups. 5/45 (11%) patients developed Grade 2 or higher lung toxicity including hospital admission in the dexamethasone premedication arm vs. 2/41 (5%) patients without premedication (p=0.4370, Fisher exact test). Freedom from acute SBRT lung toxicity was no different between dexamethasone premedication arm vs. no premedication (Log rank, p=0.45). On multivariate Cox proportional hazard modeling adjusting for age, ECOG, tumor size, central vs. peripheral, pre-treatment DLCO, BED, there was no difference in freedom from acute lung toxicity with dexamethasone premedication (HR 0.305, 95% CI: 0.033, 2.792, p =0.293).

Conclusion: In this retrospective analysis, pre-treatment steroid prophylaxis with dexamethasone confers similar acute toxicity profile to treatment without steroid prophylaxis. These results should be validated in independent datasets and prospectively with patient reported outcome instrument.

Author Disclosure: F. Alite: None. M.P. Shaikh: None. M.J. Greenberg: None. R.A. Rostock: None. A. Mahadevan: Salary; Harvard Medical Faculty Physicians. Royalty; UptoDate. Advisory Board member; Accuray Inc.

Fiori Alite, MD

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