Pulmonary function in stereotactic body radiotherapy with helical tomotherapy for primary and metastatic lung lesions

Aims: This retrospective study reports outcomes after stereotactic body radiation therapy (SBRT) as delivered by helical tomotherapy (HT) for lung lesions. It promotes a dose escalation program. Methods: Histological and/or radiological findings and/or case histories identified 41 primary and 15 metastatic lesions. Thirty patients received 40 Gy in 5 fractions (BED 72 Gy10Gy) and 26 50 Gy in 5 fractions (BED 100Gy10Gy). Primary end point was lung toxicity. Secondary end points were respiratory function, local control and local progression-free survival. Results: Acute toxicity developed in 18/56 patients and late toxicity in 8/54. Median FEV-1 variations versus baseline were − 0.5% (range − 16 to + 43%) at 6 months and − 4.00% (range − 42 to + 18%) at 24 months. Median DLCO variations versus baseline were − 1% (range − 38 to + 36%) at 6 months and − 12.2% (range − 48 to + 11%) at 24 months. At 6 months, a significant positive correlation emerged between FEV-1 change and KPS (p = 0.047). At 24 months, a significant negative correlation emerged between FEV-1 change and the ipsilateral lung V5 (p = 0.006). A low baseline DLCO correlated with more marked DLCO worsening at 6 months (p = 0.012). At 24 months, DLCO worsening correlated significantly with the median contralateral lung dose (p = 0.003). At the last checkup, 23 patients were in complete remission, 16 were in partial remission, 5 had stable disease, and 7 were in relapse. Median follow-up was 12 months (range 5–56). Conclusions: In patients with lung disease, SBRT, as delivered by HT, was well tolerated and provided good local control.