Pulmonary Function after Proton Therapy for Hodgkin Lymphoma

Acute and late toxicity from chemotherapy, targeted therapy, and radiation therapy can cause significant morbidity among survivors of Hodgkin lymphoma (HL), including pulmonary dysfunction. Improved dosimetry may influence pulmonary function tests (PFTs), an objective and clinically significant measure of pulmonary toxicity. The present study investigates the impact of proton therapy on PFTs among HL survivors.

We monitored 15 patients with mediastinal HL who were enrolled in an institutional HL trial. All patients were treated with combination chemotherapy plus involved-node proton therapy. All patients were to undergo PFTs before starting treatment and at approximately 6 and 12 months after completing proton therapy.

Twelve patients were included in the analysis and 3 excluded. The mean forced vital capacity (FVC) was 96.2% ± 16.5% (mean ± SD) predicted at baseline and 98.2% ± 19.4% predicted at 12 months. The mean forced expiratory volume in 1 second (FEV₁) was 96.7% ± 17.2% predicted at baseline and 97% ± 15.1% predicted at 12 months. The mean FEV₁/FVC ratio was 99.5 ± 8.29 at baseline and 97.8 ± 8.02 at 12 months. The mean diffusing capacity of the lung for carbon monoxide was 81.4% ± 18.4% predicted at baseline and 95.7% ± 23.5% predicted at 12 months.

No unexpected changes were observed to the lungs as illustrated through follow-up PFTs. Long-term follow-up and validation in a larger cohort are needed.