18Fluorodeoxyglucose PET is prognostic of progression-free and overall survival in locally advanced pancreas cancer treated with stereotactic radiotherapy.
OBJECTIVE
This study analyzed the prognostic value of positron emission tomography (PET) for locally advanced pancreas cancer patients undergoing stereotactic body radiotherapy (SBRT).


METHODS
Fifty-five previously untreated, unresectable pancreas cancer patients received a single fraction of 25-Gy SBRT sequentially with gemcitabine-based chemotherapy. On the preradiation PET-CT, the tumor was contoured and the maximum standardized uptake value (SUVmax) and metabolic tumor burden (MTB) were calculated using an in-house software application. High-SUVmax and low-SUVmax subgroups were created by categorizing patients above or below the median SUVmax. The analysis was repeated to form high-MTB and low-MTB subgroups as well as clinically relevant subgroups with SUVmax values of <5, 5-10, or >10. Multivariate analysis analyzing SUVmax, MTB, age, chemotherapy cycles, and pretreatment carbohydrate antigen (CA)19-9 was performed.


RESULTS
For the entire population, median survival was 12.7 months. Median survival was 9.8 vs.15.3 months for the high- and low- SUVmax subgroups (p <0.01). Similarly, median survival was 10.1 vs. 18.0 months for the high MTB and low MTB subgroups (p <0.01). When clinical SUVmax cutoffs were used, median survival was 6.4 months in those with SUVmax >10, 9.5 months with SUVmax 5.0-10.0, and 17.7 months in those with SUVmax <5 (p <0.01). On multivariate analysis, clinical SUVmax was an independent predictor for overall survival (p = 0.03) and progression-free survival (p = 0.03).


CONCLUSIONS
PET scan parameters can predict for length of survival in locally advanced pancreas cancer patients.
Schellenberg
Devin
D
Department of Radiation Oncology at Fraser Valley Cancer Centre, Surrey, Canada.
Quon
Andy
A
Minn
A Yuriko
AY
Graves
Edward E
EE
Kunz
Pamela
P
Ford
James M
JM
Fisher
George A
GA
Goodman
Karyn A
KA
Koong
Albert C
AC
Chang
Daniel T
DT
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use; D018395:CA-19-9 Antigen / Q000097:blood; D003841:Deoxycytidine / Q000031:analogs & derivatives / Q000627:therapeutic use; D018572:Disease-Free Survival; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008875:Middle Aged; D015999:Multivariate Analysis; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000401:mortality / Q000601:surgery; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D016634:Radiosurgery; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D000093542:Gemcitabine
D000964:Antimetabolites, Antineoplastic; D018395:CA-19-9 Antigen; D019275:Radiopharmaceuticals; D003841:Deoxycytidine; D019788:Fluorodeoxyglucose F18; D000093542:Gemcitabine