PURPOSE: We evaluated the impact of overall treatment time on the disease-free survival (DFS) and local control after radiotherapy for nonsmall cell lung carcinoma. METHODS AND MATERIALS: One hundred fifty-three cases considered as responders to radiotherapy were retrospectively analyzed. Patients with Karnofsky status < 70, pretreated with chemotherapy and with pleural or pericardial effusion, were excluded from the analysis. Radiation dose homogenization was done with calculation of the normalized total dose without (NTD) and with time correction (NTD-T) for alpha/beta = 10 Gy. RESULTS: Kaplan-Meier curves for 2-year DFS showed that any analysis based on radiation dose can prove to be erroneous when the time factor is neglected. Although there was no difference between the 47-55 Gy and 56-64 Gy NTD groups, a log rank test revealed a strong difference (p < 0.0002) between NTD-T groups. No difference was observed for patients with mediastinal involvement. Logistic regression analysis showed a statistical association of dose on 2-year local progression-free probability for different time compartments. For those cases without mediastinal involvement, the daily dose lost because of treatment protraction beyond 20 days after the beginning of radiotherapy was estimated to 0.2 Gy/day. When all cases were considered together this was calculated to 0.45 Gy/day. CONCLUSION: Time factor should not be underestimated when evaluating the results of radiotherapy for nonsmall cell lung cancer. There is strong evidence that prolonged overall treatment time could be a major cause of the failure of radiotherapy to control the local disease.
PURPOSE: We evaluated the impact of overall treatment time on the disease-free survival (DFS) and local control after radiotherapy for nonsmall cell lung carcinoma. METHODS AND MATERIALS: One hundred fifty-three cases considered as responders to radiotherapy were retrospectively analyzed. Patients with Karnofsky status < 70, pretreated with chemotherapy and with pleural or pericardial effusion, were excluded from the analysis. Radiation dose homogenization was done with calculation of the normalized total dose without (NTD) and with time correction (NTD-T) for alpha/beta = 10 Gy. RESULTS: Kaplan-Meier curves for 2-year DFS showed that any analysis based on radiation dose can prove to be erroneous when the time factor is neglected. Although there was no difference between the 47-55 Gy and 56-64 Gy NTD groups, a log rank test revealed a strong difference (p < 0.0002) between NTD-T groups. No difference was observed for patients with mediastinal involvement. Logistic regression analysis showed a statistical association of dose on 2-year local progression-free probability for different time compartments. For those cases without mediastinal involvement, the daily dose lost because of treatment protraction beyond 20 days after the beginning of radiotherapy was estimated to 0.2 Gy/day. When all cases were considered together this was calculated to 0.45 Gy/day. CONCLUSION: Time factor should not be underestimated when evaluating the results of radiotherapy for nonsmall cell lung cancer. There is strong evidence that prolonged overall treatment time could be a major cause of the failure of radiotherapy to control the local disease.
Authors: Matthew P Deek; Sinae Kim; Inaya Ahmed; Bruno S Fang; Wei Zou; Jyoti Malhotra; Joseph Aisner; Salma K Jabbour Journal: Am J Clin Oncol Date: 2018-04 Impact factor: 2.339
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Authors: Yanqun Dong; Nicholas G Zaorsky; Tianyu Li; Thomas M Churilla; Rosalia Viterbo; Mark L Sobczak; Marc C Smaldone; David Yt Chen; Robert G Uzzo; Mark A Hallman; Eric M Horwitz Journal: J Med Imaging Radiat Oncol Date: 2017-10-13 Impact factor: 1.735
Authors: Jeffrey A Bogart; Dorothy Watson; Edward F McClay; Lisa Evans; James E Herndon; Frances Laurie; Stephen L Seagren; T J Fitzgerald; Everett Vokes; Mark R Green Journal: Lung Cancer Date: 2008-03-25 Impact factor: 5.705
Authors: M I Saunders; A Rojas; B E Lyn; K Pigott; M Powell; K Goodchild; P J Hoskin; H Phillips; N Verma Journal: Br J Cancer Date: 1998-11 Impact factor: 7.640