To determine histogram analysis of diffusion kurtosis imaging (DKI) in evaluating the prognostic factors for a locally advanced rectal cancer (LARC) treated with neoadjuvant chemoradiation therapy (NCRT).
Methods:
A total of 61 patients with rectal cancer were retrospectively collected and followed in Fudan University Shanghai Cancer Center between January 2015 and December 2017. All patients received NCRT followed by total mesorectal excision. The enrolled patients were examined using pretreatment magnetic resonance imaging (MRI) within 1week before NCRT. Pretreatment T stage
N stage
mesorectal fascia (MRF)
extramural vascular invasion (EMVI)
tumor location and length
pretreatment carcinoembryonic antigen (CEA) and carbohydrate antigen (CA)19-9 levels were recorded. Tumor response
perineural invasion (PNI) and lymphovascular invasion (LVI) were evaluated. Whole tumor volume of interest (VOI) was obtained by semi-automatic segmentation method in pretreatment MRI. Then
K and D histograms and corresponding parameters were calculated. The predictor of OS was analyzed by using Cox proportional hazards model.
Results:
Pretreatment D
Skewness
predicted patients OS status with an optimal diagnostic cut-off value of 0.588 and an area under curve (AUC) of 0.678 (
P
=0.044). The mrEMVI (+) [HR=9.796 (2.623-36.580)
P
=0.001]
mrMRF (+) [HR=7.140 (1.929-26.429)
P
=0.003]
CA19-9 (+) [HR=5.111 (1.634-15.993)
P
=0.006]
high pretreatment D
Skewness
[HR=4.054 (1.043-22.888)
P
=0.044] and PNI (+) [HR=6.021 (1.206-30.053)
P
=0.029) could be associated with worse OS in
univariate analysis. Multivariate analysis identified the mrEMVI (+) [HR=12.163 (2.714-54.514)
P
=0.001]
CA19-9 (+) [HR=5.032 (1.440-17.577)
P
=0.011] and high pretreatment D
Skewness
[HR=13.518 (2.000-91.378)
P
=0.008] were independent risk predictors for worse OS.
Conclusion:
Pretreatment D
Skewness
can be as a predictor for OS in LARC patients. DKI histogram can be used to predict survival of LARC patients.