Predictors of radiation pneumonitis after radiotherapy in lung cancer

Abstract

We have read with interest recent article by de Jaeger et al. ( 1 De Jaeger K. Seppenwolde Y. Kampinga H.H. et al. Significance of plasma transforming growth factor-β levels in radiotherapy for non-small-cell lung cancer. Int J Radiat Oncol Biol Phys. 2004; 58: 1378-1387 Abstract Full Text Full Text PDF PubMed Scopus (82) Google Scholar ) on the significance of plasma transforming growth factor (TGF)-β levels in radiotherapy (RT) of non–small-cell lung cancer. They have used multivariate analysis to show that, of three factors examined, plasma TGF-β levels at the end of RT is not an independent prognosticator of symptomatic radiation pneumonitis (RP). Although the authors acknowledged the importance of various pretreatment- ( 2 Yorke E.D. Jackson A. Rosenzweig K. et al. Dose-volume factors contributing to the incidence of radiation pneumonitis in non-small cell lung cancer patients treated with three-dimensional conformal radiation therapy. Int J Radiat Oncol Biol Phys. 2002; 54: 329-339 Abstract Full Text Full Text PDF PubMed Scopus (257) Google Scholar , 3 Lind P.A. Marks L.B. Hollis D. et al. Receiver operating characteristic curves to assess predictors of radiation-induced symptomatic lung injury. Int J Radiat Oncol Biol Phys. 2002; 4: 340-347 Abstract Full Text Full Text PDF Scopus (86) Google Scholar , 4 Johansson S. Bjemer L. Franzen L. et al. Effects of ongoing smoking on the development of radiation-induced pneumonitis in breast cancer and esophagus cancer patients. Radiother Oncol. 1998; 49: 41-47 Abstract Full Text Full Text PDF PubMed Scopus (88) Google Scholar , 5 Moiseenko V.V. Battista J.J. Hill R.P. et al. In-field and out-of-field effects in partial volume lung irradiation in rodents: Possible correlation between early DNA damage and functional endpoints. Int J Radiat Oncol Biol Phys. 2000; 48: 1539-1548 Abstract Full Text Full Text PDF PubMed Scopus (40) Google Scholar ) and treatment-related factors ( 6 Van Dyk J. Keane T.J. Kan S. et al. Radiation pneumonitis following large single dose irradiation: A re-evaluation based on absolute dose to lung. Int J Radiat Oncol Biol Phys. 1981; 7: 461-467 Abstract Full Text PDF PubMed Scopus (216) Google Scholar , 7 Rothwell R.I. Kelly S.A. Joslin C.A. Radiation pneumonitis in patients treated for breast cancer. Radiother Oncol. 1985; 4: 9-14 Abstract Full Text PDF PubMed Scopus (105) Google Scholar , 8 Emami B. Lyman J. Brown A. et al. Tolerance of normal tissue to therapeutic irradiation. Int J Radiat Oncol Biol Phys. 1991; 21: 109-122 Abstract Full Text PDF PubMed Scopus (3453) Google Scholar , 9 Van Dyk J. Mah K. Keane T.J. Radiation-induced lung damage: Dose-time-fractionation considerations. Radiother Oncol. 1989; 14: 55-59 Abstract Full Text PDF PubMed Scopus (106) Google Scholar , 10 Mah K. Keane T.J. van Dyk J. et al. Quantitative effect of combined chemotherapy and fractionated radiotherapy on the incidence of radiation-induced lung damage: A prospective clinical study. Int J Radiat Oncol Biol Phys. 1994; 28: 563-574 Abstract Full Text PDF PubMed Scopus (60) Google Scholar , 11 Tsujino K. Hirota S. Endo M. et al. Predictive values of dose-volume histograms parameters for predicting radiation pneumonitis after concurrent chemoradiation for lung cancer. Int J Radiat Oncol Biol Phys. 2003; 55: 110-115 Abstract Full Text Full Text PDF PubMed Scopus (292) Google Scholar ) in the occurrence of RP, none of these factors has been taken into account to correct for possible influence on the occurrence of RP. This is especially important because one-half of their patients were stage I/II, likely to be the one usually labeled as “technically operable but medically inoperable,” having, therefore, a number of concomitant diseases. The median age of their patients was 74 years, which would suggest a rather elderly population, whereas their range of doses (61–95 Gy) could also have been used to further evaluate the relationship between various factors, including various histologies or plasma TGF-β levels and the occurrence of RP. This is especially important because the findings could have also been influenced by the low number of patients or by the broad range of normal TGF-β values even in healthy individuals. Unfortunately, the authors investigated the impact of plasma TGF-β levels, correcting its influence with only two other covariates used.