Dose-volume factors predicting radiation pneumonitis in patients receiving salvage radiotherapy for postlobectomy locoregional recurrent non-small-cell lung cancer.
BACKGROUND
The correlation between treatment-related factors and lung toxicity has not been sufficiently evaluated in salvage radiotherapy.


METHODS
Twenty-one patients with recurrent non-small-cell lung cancer (NSCLC) after lobectomy received salvage radiotherapy to a total dose of 46-60 Gy. The effects of radiotherapy parameters on the development of radiation pneumonitis (RP) were examined using dose-volume histograms.


RESULTS
Grade 1 RP was observed in 4, grade 2 in 2, and grade 3 in 1 patient. Patients who developed RP had a significantly higher value in V dose (V13, V20) parameters and mean lung dose (MLD) than those who did not develop RP. Concerning G2 or higher RP, 3 patients who developed > or = G2 RP had a significantly higher value in V20, V13, and MLD than the remaining patients with P values of 0.01, 0.015, and 0.016, respectively. The mean V20, V13, and MLD in these 3 patients were 27%, 29.3%, and 14.8 Gy, respectively, whereas the mean V20, V13, and MLD in the remaining 18 patients were 15.8%, 18.3%, and 8.8 Gy, respectively. Three of 6 patients with a V20 > or = 20% developed > or = G2 RP whereas this did not occur in the remaining patients (P = 0.015). Similarly, 3 of 6 patients with a V13 > or = 23% developed > or = G2 RP whereas this did not occur in the remaining patients (P = 0.015).


CONCLUSIONS
These data suggest that a somewhat lower V dose value or MLD, as compared with the setting of definitive radiotherapy, could be a surrogate for RP in patients undergoing salvage radiotherapy for recurrent NSCLC.
Uno
Takashi
T
Department of Radiology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba, 260-8670, Japan. unotakas@faculty.chiba-u.jp
Isobe
Koichi
K
Kawakami
Hiroyuki
H
Ueno
Naoyuki
N
Kawata
Tetsuya
T
Yamamoto
Seiji
S
Sekine
Yasuo
Y
Iyoda
Akira
A
Iizasa
Toshihiko
T
Fujisawa
Takehiko
T
Shigematsu
Naoyuki
N
Ito
Hisao
H
D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000532:radiotherapy* / Q000601:surgery; D003131:Combined Modality Therapy; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000532:radiotherapy* / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D017564:Radiation Pneumonitis / Q000209:etiology*; D011879:Radiotherapy Dosage; D016879:Salvage Therapy