The Potential Role of Lung Ultrasound B-Lines for Detection of Lung Radio-Induced Toxicity in Breast Cancer Patients after Radiation Therapy.

BACKGROUND AND PURPOSE: Breast cancer patients exposed to doses of radiation after radiotherapy could develop toxicity to lung. Lung ultrasound (LUS) is able to detect interstitial lung disease by the evaluation of B-lines. The aim of our study was to assess the number of B-lines to diagnose lung involvement after chest radiotherapy.

MATERIALS AND

METHODS

We measured LUS B-lines in the treated and contralateral lung of 20 breast cancer patients, 1-3 months after the end of radiotherapy and 1 year after previous LUS. The sum of the B-lines number in the 72 sites on anterior and posterior chest yielded a global B-lines score.

RESULTS

B-lines were more numerous in treated (median: 21; 1st-3rd quartiles: 11-31) versus untreated hemithorax (median: 3; 1st-3rd quartiles: 1-5) in both examination at T1-3 months (Kolmogorov-Smirnov test P < 0.001) and T1 year (median: 21; 1st-3rd quartiles: 12-28 vs. median: 4; 1st-3rd quartiles: 1-10; Kolmogorov-Smirnov test P < 0.01). Within the treated hemithorax, B-lines were more frequent in the anterior than in the posterior chest in both examination at T1-3 months (Kolmogorov-Smirnov test: P < 0.0001) and T1 year (Kolmogorov-Smirnov test: P < 0.01). Abnormal scores (B-lines>5) were present in 17/20 treated versus 7/20 untreated hemithoraxes (85.0 vs. 35.0%, P < 0.01) in the first LUS and likewise in 16/17 treated versus 7/17 in untreated hemithorax (94.1% vs. 41.2%, P < 0.01) after 1-year follow-up.

CONCLUSION

Among women receiving radiotherapy after breast cancer, B-lines are present predominantly in the irradiated lung. These data suggest that B-lines by LUS could provide, at a subclinical stage, a radiation-free biomarker of radiotherapy-induced lung damage.