Predictor of severe gastroduodenal toxicity after stereotactic body radiotherapy for abdominopelvic malignancies.
OBJECTIVE
To identify the predictors for the development of severe gastroduodenal toxicity (GDT) in patients treated with stereotactic body radiotherapy (SBRT) using 3 fractionations for abdominopelvic malignancies.


METHODS
From 2001 to 2011, 202 patients with abdominopelvic malignancies were treated with curative-intent SBRT. Among these patients, we retrospectively reviewed the clinical records of 40 patients with the eligibility criteria as follows: 3 fractionations, follow-up period≥1 year, absence of previous radiation therapy (RT) history or combination of external-beam RT and the presence of gastroduodenum (GD) that received a dose higher than 20% of prescribed dose. The median SBRT dose was 45 Gy (range, 33-60 Gy) with 3 fractions. We analyzed the clinical and dosimetric parameters, including multiple dose-volume histogram endpoints: V20 (volume of GD that received 20 Gy), V25, V30, V35, and Dmax (the maximum point dose). The grade of GDT was defined by the National Cancer Institute Common Toxicity Criteria version 4.0, and GDT≥grade 3 was defined as severe GDT.


RESULTS
The median time to the development of severe GDT was 6 months (range, 3-12 months). Severe GDT was found in 6 patients (15%). Dmax was the best dosimetric predictor for severe GDT. Dmax of 35 Gy and 38 Gy were respectively associated with a 5% and 10% probability of the development of severe GDT. A history of ulcer before SBRT was the best clinical predictor on univariate analysis (P=.0001).


CONCLUSIONS
We suggest that Dmax is a valuable predictor of severe GDT after SBRT using 3 fractionations for abdominopelvic malignancies. A history of ulcer before SBRT should be carefully considered as a clinical predictor, especially in patients who receive a high dose to GD.
Department of Radiation Oncology, Korea Institute of Radiological & Medical Sciences, Seoul, Korea.
Sun Hyun
SH
Bae
Mi-Sook
MS
Kim
Chul Koo
CK
Cho
Jin-Kyu
JK
Kang
Sang Yeob
SY
Lee
Kyung-Nam
KN
Lee
Dong Han
DH
Lee
Chul Ju
CJ
Han
Ki Young
KY
Yang
Sang Bum
SB
Kim
D000008:Abdominal Neoplasms / Q000473:pathology / Q000601:surgery*; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D019583:Dose Fractionation, Radiation; D004386:Duodenum / Q000528:radiation effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D058958:Organs at Risk / Q000528:radiation effects*; D010386:Pelvic Neoplasms / Q000473:pathology / Q000601:surgery*; D012372:ROC Curve; D016634:Radiosurgery / Q000009:adverse effects*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D012189:Retrospective Studies; D013270:Stomach / Q000528:radiation effects*; D013997:Time Factors; D047368:Tumor Burden