2441. MRI Features at Baseline are Predictive of Rectal Cancer Recurrence and Metastases in Surgically Resected Cancers
Authors * Denotes Presenting Author
  1. Maria El Homsi *; Memorial Sloan Kettering Cancer Center
  2. Sidra Javed-Tayyab; Memorial Sloan Kettering Cancer Center
  3. Charlotte Charbel; Ichan School of Medicine at Mount Sinai
  4. Jennifer Golia Pernicka; Memorial Sloan Kettering Cancer Center
  5. Victoriya Paroder; Memorial Sloan Kettering Cancer Center
  6. Charlie White; Memorial Sloan Kettering Cancer Center
  7. Iva Petkovska; Memorial Sloan Kettering Cancer Center
To assess imaging predictive features on baseline MRI rectum of local recurrence (LR) and/or metastatic disease (MD) after surgical resection.

Materials and Methods:
This is a retrospective study including 284 consecutive patients (150 M/ 134 F, mean age 55.3 y) with rectal cancer who underwent surgical resection between January 2015 and December 2017. Baseline MRI rectum characteristics were obtained from the synoptic report and patients were followed after surgery to detect LR and/or MD. The study of the recurrence rate and prognostic factors was performed through the Kaplan Meier survival curve. Log-rank test was used to test for difference in recurrence probabilities between groups for 18 imaging variables.

Patients were followed for a median of 4.8 years and median to LR and/or DM was 4.29 years, [1.78, 5.05]. A total of 8 patients (2.8%) had LR, 44 (15%) had MD , 17 (6.0%) had both LR and MD and 215 (76%) were disease-free. The following features were predictive of LR and/or MD: Tumor below anterior peritoneal reflection (p=0.04), N+ stage (p=0.09), T4a stage (p=0.012), distance from the mesorectal fascia of 0.1-0.2cm (p=0.004), involvement of the anal canal (p=0.027), presence of TME lymph nodes >0.5 cm (p <0.001), presence of extra-TME lymph nodes >0.7cm (p=0.007), distance less than 1cm from sphincter complex (p=0.004) and craniocaudal length > 5cm (p=0.009).

Predictive imaging features from baseline MRI of LR or MD of rectal adenocarcinoma after curative surgery may aid to define the high-risk patients for recurrence.