programma & abstracts - Nederlandse Vereniging voor Radiologie

1 programma Abstracts & abstracts
Sessie 1
Abdominale radiologie 1
Donderdag 29 september, 14.05 - 15.35 uur
O1.1
RESTAGING NODAL STATUS AFTER CHEMO-
RADIATION FOR LOCALLY ADVANCED
RECTAL CANCER: PREDICTIVE FACTORS
M. Maas, D.M.J. Lambregts, M. Berkhof, G.L. Beets,
R.G.H. Beets-Tan
Maastricht Universitair Medisch Centrum, Maastricht
Purpose: Restaging N-stage after CRT for rectal cancer is
more accurate than N-stage prediction at primary staging
of rectal cancer. The aim was to identify predictive factors
which can help a radiologist in predicting the yN-stage.
Methods: 39 patients with locally advanced rectal cancer
underwent MRI before and after CRT. All visible nodes in
the mesorectum were measured and recorded before and
after CRT on a 3DT1W GRE-sequence with 1mm3 voxels.
Baseline characteristics were collected and compared between
patients with and without nodal involvement at pathology
with t-tests and χ2. With regression analyses predictive
factors for nodal involvement after CRT were identified.
Based on the regression analyses a predictive model for yNstage
was constructed and ROC curves were constructed for
this predictive model.
Results: 895 nodes were identified, of which 392 (44%)
disappeared after CRT. Patients with ypN+ had larger nodes
than ypN0-patients: mean 6.3 vs 3.6mm before CRT and 4.5
vs 2.3mm after CRT, respectively (both p