The Effect of Pentoxifylline and Vitamin E in Preventing Grade 3 Radiation Pneumonitis: A Single-Arm, Phase II Prospective Study

Objective/Hypothesis Stereotactic ablative radiation therapy (SABR) is becoming an increasingly popular treatment for patients with recurrent non-small cell lung cancer. Thoracic reirradiation, however, can be toxic, with some institutions reporting grade 3 pneumonitis in upward of 30% of reirradiated patients. Pentoxifylline (PTX) and vitamin E (VE) have mitigated toxicity in standard breast treatment and may be beneficial in the reduction of radiation-induced pneumonitis. The objective of this study is to prospectively evaluate the efficacy of PTX and VE in reducing grade 3 pneumonitis in patients undergoing SABR with locoregionally recurrent lung cancer or new lung primary tumors in the setting of prior thoracic radiation. We hypothesize that these patients will experience rates of grade 3 pneumonitis lower than 30% at 3, 6, and 12 months post-treatment. Materials and Methods Patients who received radiation for a prior thoracic malignancy with a diagnosis of a recurrent or new NSCLC were recruited from our institution. PTX and VE were administered at the time of simulation, approximately 1 week prior to starting treatment, and were continued for 12 weeks post-treatment. SABR was delivered using standard stereotactic techniques to a dose of 50 Gy at 10 Gy per fraction over 2 weeks. Clinical and radiographic assessment of pneumonitis was conducted at 3, 6, and 12 months post-treatment. Demographic information was collected before treatment. Results The rate of grade 3 pneumonitis in our PTX- and VE-treated cohort was significantly lower than 30% at 3 months (0%, 95% CI 0%-11%, P = .001), 6 months (5%, 95% CI 0%-20%, P = .004), and 12 months (0%, 95% CI 0%-21%, P = .010) post-treatment. Also, 92% of participants were medication compliant. Conclusion PTX and VE are safe interventions that may reduce rates of grade 3 pneumonitis for patients undergoing reirradiation for locoregionally recurrent and/or new lung primary tumors.