Late gastrointestinal tissue effects after hypofractionated radiation therapy of the pancreas.
BACKGROUND
To consolidate literature reports of serious late gastrointestinal toxicities after hypofractionated radiation treatment of pancreatic cancer and attempt to derive normal tissue complication probability (NTCP) parameters using the Lyman-Kutcher-Burman model.


METHODS
Published reports of late grade 3 or greater gastrointestinal toxicity after hypofractionated treatment of pancreatic cancer were reviewed. The biologically equivalent dose in 1.8 Gy fractions was calculated using the EQD model. NTCP parameters were calculated using the LKB model assuming 1-5% of the normal tissue volume was exposed to the prescription dose with α/β ratios of 3 or 4.


RESULTS
A total of 16 human studies were examined encompassing a total of 1160 patients. Toxicities consisted of ulcers, hemorrhages, obstructions, strictures, and perforations. Non-hemorrhagic and non-perforated ulcers occurred at a rate of 9.1% and were the most commonly reported toxicity. Derived NTCP parameter ranges were as follows: n = 0.38-0.63, m = 0.48-0.49, and TD50 = 35-95 Gy. Regression analysis showed that among various study characteristics, dose was the only significant predictor of toxicity.


CONCLUSIONS
Published gastrointestinal toxicity reports after hypofractionated radiotherapy for pancreatic cancer were compiled. Median dose was predictive of late grade ≥ 3 gastrointestinal toxicity. Preliminary NTCP parameters were derived for multiple volume constraints.
Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, MO, 63110-63110, USA. adnan.elhammali@gmail.com.
Adnan
A
Elhammali
Department of Radiation Oncology, The Brody School of Medicine at East Carolina University, Greenville, NC, USA. patelm09@outlook.com.
Mukund
M
Patel
Department of Radiation Oncology, Wayne State University, Detroit, MI, USA. benweinberg@gmail.com.
Benjamin
B
Weinberg
Department of Radiation Oncology, University of Nebraska Medical Center, Omaha, NE, USA. Vivek333@gmail.com.
Vivek
V
Verma
Division of Biostatistics, Washington University School of Medicine, St. Louis, MO, USA. esther@wubios.wustl.edu.
Jingxia
J
Liu
Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, MO, 63110-63110, USA. jolsen@radonc.wustl.edu.
Jeffrey R
JR
Olsen
Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, MO, 63110-63110, USA. hgay@radonc.wustl.edu.
Hiram A
HA
Gay
D041981:Gastrointestinal Tract / Q000528:radiation effects*; D006801:Humans; D010190:Pancreatic Neoplasms / Q000532:radiotherapy*; D000069473:Radiation Dose Hypofractionation; D011832:Radiation Injuries / Q000453:epidemiology / Q000209:etiology; D011878:Radiotherapy / Q000009:adverse effects*