Selection of colon cancer patients for neoadjuvant chemotherapy based on optimised preoperative MDCT A prospective multi-observer radiologic-pathologic agreement study
PURPOSE: Neoadjuvant chemotherapy (NACT) in potencially-resectable locally advanced colon cancer (LACC) is likely to prove superiority compared to standard treatment in the phase III FOXTROT Collaborative Group Trial. Thus, identification of LACC, defined as T3≥5 mm or T4, is fundamental and requires accurate noninvasive imaging. The value of optimized preoperative MDCT for that purpose is being assessed.
METHODS AND MATERIALS: Observational, cross-sectional, prospective study including all patients with colon cancer refered to our Institution´s Radiology Department for preoperative staging between the 1st of October 2013 and the 6th of August 2014. Independent reading of optimized MDCT acquisitions using MPR was performed by 4 radiologists (3.6,15 and 20 years of experience in gastrointestinal imaging). Extramural tumour extension was graded as < 5 mm; ≥5 mm; invasion of peritoneum/fascia/adjacent organ. Surgical specimen analysis was performed by a single pathologist with 12 years of experience in gastrointestinal pathology. Radiologic-Pathologic agreement was assessed.
RESULTS: 48 patients, 26 males and 22 females, with a median age of 74 years (min:45;max:89) were considered eligible. Median time to surgery was 30.5 days (min:1;max:117). Diagnostic sensitivity, specificity, positive predictive value, negative predictive value and accuracy of MDCT for the identification of LACC ranged between 0.64 and 0.82; 0.84 and 0.92; 0.5 and 0.7; 0.88 and 0.97; 0.75 and 0.88; respectively. Mean agreement between observers was 0.88 (SD:0.17) per patient.
CONCLUSION: Preliminary results suggest that optimized MDCT is a specific, accurate and reproducible method for the selection of colon cancer patients who may benefit from NACT, with minimal risk of overtreatment of low-risk patients
