A pilot study of diffusion-weighted MRI in patients undergoing neoadjuvant chemoradiation for pancreatic cancer.
OBJECTIVE
In the current study we examined the ability of diffusion MRI (dMRI) to predict pathologic response in pancreatic cancer patients receiving neoadjuvant chemoradiation.


METHODS
We performed a prospective pilot study of dMRI in patients with resectable pancreatic cancer. Patients underwent dMRI prior to neoadjuvant chemoradiation. Surgical specimens were graded according to the percent tumor cell destruction. Apparent diffusion coefficient (ADC) maps were used to generate whole-tumor derived ADC histogram distributions and mean ADC values. The primary objective of the study was to correlate ADC parameters with pathologic and CT response.


RESULTS
Ten of the 12 patients enrolled on the study completed chemoradiation and had surgery. Three were found to be unresectable at the time of surgery and no specimen was obtained. Out of the 7 patients who underwent pancreaticoduodenectomy, 3 had a grade III histopathologic response (> 90% tumor cell destruction), 2 had a grade IIB response (51% to 90% tumor cell destruction), 1 had a grade IIA response (11% to 50% tumor cell destruction), and 1 had a grade I response (> 90% viable tumor). Median survival for patients with a grade III response, grade I-II response, and unresectable disease were 25.6, 18.7, and 6.1 months, respectively. There was a significant correlation between pre-treatment mean tumor ADC values and the amount of tumor cell destruction after chemoradiation with a Pearson correlation coefficient of 0.94 (P = .001). Mean pre-treatment ADC was 161 × 10(- 5) mm(2)/s (n = 3) in responding patients (> 90% tumor cell destruction) compared to 125 × 10(- 5) mm(2)/s (n = 4) in non-responding patients (> 10% viable tumor). CT imaging showed no significant change in tumor size in responders or non-responders.


CONCLUSIONS
dMRI may be useful to predict response to chemoradiation in pancreatic cancer. In our study, tumors with a low ADC mean value at baseline responded poorly to standard chemoradiation and would be candidates for intensified therapy.
Department of Radiation Oncology, University of Michigan, Ann Arbor, MI ; Department of Radiation Oncology, Ann Arbor Veterans Affairs Hospital, Ann Arbor, MI.
Kyle C
KC
Cuneo
Department of Radiology, University of Michigan, Ann Arbor, MI.
Thomas L
TL
Chenevert
Department of Radiation Oncology, University of Michigan, Ann Arbor, MI.
Edgar
E
Ben-Josef
Department of Radiation Oncology, University of Michigan, Ann Arbor, MI.
Mary U
MU
Feng
Department of Pathology, University of Michigan, Ann Arbor, MI.
Joel K
JK
Greenson
Department of Radiology, University of Michigan, Ann Arbor, MI.
Hero K
HK
Hussain
Department of Surgery, University of Michigan, Ann Arbor, MI.
Diane M
DM
Simeone
Department of Statistics, University of Michigan, Ann Arbor, MI.
Matthew J
MJ
Schipper
Department of Medicine-Gastroenterology, University of Michigan, Ann Arbor, MI.
Michelle A
MA
Anderson
Department of Medicine-Oncology, University of Michigan, Ann Arbor, MI.
Mark M
MM
Zalupski
Department of Radiology, University of Michigan, Ann Arbor, MI.
Mahmoud
M
Al-Hawary
Department of Radiology, University of Michigan, Ann Arbor, MI ; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI.
Craig J
CJ
Galban
Department of Radiation Oncology, University of Michigan, Ann Arbor, MI.
Alnawaz
A
Rehemtulla
Department of Radiation Oncology, University of Michigan, Ann Arbor, MI.
Felix Y
FY
Feng
Department of Radiation Oncology, University of Michigan, Ann Arbor, MI.
Theodore S
TS
Lawrence
Department of Radiology, University of Michigan, Ann Arbor, MI.
Brian D
BD
Ross