[Dosimetric comparison between intensity-modulated radiotherapy and conformal radiotherapy for upper thoracic esophageal carcinoma].
OBJECTIVE
Treatment planning for radiotherapy of upper thoracic esophageal carcinoma is challenging due to the anatomical features. The difficulty may be resolved by intensity-modulated radiotherapy (IMRT). This study was to compare the dosimetric advantages of IMRT to that of conformal radiotherapy (CRT) for upper thoracic esophageal carcinoma, and to explore the clinical application of IMRT.


METHODS
Eleven patients with upper thoracic esophageal carcinoma were enrolled. In addition to the actually used CRT plan, a five-field IMRT plan was generated for each case. The parameters of dose volume histogram for targets and organs at risk were compared between two techniques.


RESULTS
For the planning target volume (PTV) of tumor and para-tumor tissues, the mean dose, maximal dose, doses covering 99% and 95% volume were similar in IMRT and CRT plans (P>0.05). However, IMRT plan had a higher conformity index than CRT plan (0.68+/-0.04 vs. 0.46+/-0.11, P<0.01). For the PTV of supraclavicular region, IMRT plan showed a better dose heterogeneity index than CRT plan (1.17+/-0.05 vs. 1.33+/-0.15, P=0.01). IMRT plan had lower maximal dose to the planning risk volume of the spinal cord (44.4 Gy vs. 52.5 Gy, P<0.05) and lower lung volume received dose of 10 Gy or higher [(32+/-6)% vs. (35+/-9)%, P<0.05] than CRT plan.


CONCLUSIONS
For the upper thoracic esophageal carcinoma, IMRT has more conformal distribution of dose and better spinal cord sparing than CRT, and can reduce the volume of lung that received dose of 10 Gy or higher.
Zhang
Wu-Zhe
WZ
Department of Radiation Oncology, Cancer Hospital, Shantou University Medical College, Guangdong, P. R. China.
Chen
Zhi-Jian
ZJ
Li
De-Rui
DR
Lin
Zhi-Xiong
ZX
Li
Dong-Sheng
DS
Chen
Chuang-Zhen
CZ
D004307:Dose-Response Relationship, Radiation; D004938:Esophageal Neoplasms / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008168:Lung / Q000528:radiation effects; D008297:Male; D058958:Organs at Risk; D011874:Radiometry; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D013116:Spinal Cord / Q000528:radiation effects