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

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.

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 Gy_10Gy) and 26 50 Gy in 5 fractions (BED 100Gy_10Gy). Primary end point was lung toxicity. Secondary end points were respiratory function, local control and local progression-free survival.

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).

In patients with lung disease, SBRT, as delivered by HT, was well tolerated and provided good local control.