Correlation between lung fibrosis and radiation therapy dose after concurrent radiation therapy and chemotherapy for limited small cell lung cancer

Citation
Ii. Rosen et al., Correlation between lung fibrosis and radiation therapy dose after concurrent radiation therapy and chemotherapy for limited small cell lung cancer, RADIOLOGY, 221(3), 2001, pp. 614-622
Citations number
14
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging","Medical Research Diagnosis & Treatment
Journal title
RADIOLOGY
ISSN journal
0033-8419 → ACNP
Volume
221
Issue
3
Year of publication
2001
Pages
614 - 622
Database
ISI
SICI code
0033-8419(200112)221:3<614:CBLFAR>2.0.ZU;2-R
Abstract
PURPOSE: To evaluate the relationship between physician-identified radiogra phic fibrosis, lung tissue physical density change, and radiation dose afte r Concurrent radiation therapy and chemotherapy for limited small cell lung cancer. MATERIALS AND METHODS: Fibrosis volumes of different severity levels were d elineated on computed tomography (CT) images obtained at 1-year follow-up o f 21 patients with complete response to concurrent radiation therapy and ch emotherapy for limited small cell lung carcinoma. Delivered treatments were reconstructed with a three-dimensional treatment planning system and geome trically registered to the follow-up CT images. Tissue physical density cha nge and radiation dose were computed for each voxel within each fibrosis vo lume and within normal lung. Patient responses were grouped per radiation a nd chemotherapy protocol. RESULTS: A significant correlation was noted between fibrosis grade and tis sue physical density change and fibrosis grade. For doses less than 30 Gy, the probability of observing fibrosis was less than 2% with conventional fr actionation and less than 4% with accelerated fractionation. Physical lung density change also showed a threshold of 30-35 Gy. For doses of 30-55 Gy a nd cisplatin and etoposide (PE) chemotherapy, fibrosis probability was 2.0 times greater for accelerated fractionation compared with conventional frac tionation (P < .005) and was correlated to increasing dose for both fractio nation schedules. CONCLUSION: Lung tissue physical density changes correlated well with fibro sis incidence, and both increased with increasing dose greater than a thres hold of 30-35 Gy. With concurrent PE chemotherapy, fibrosis probability was twice as great with accelerated fractionation as with once-daily fractiona tion.