Can the mesorectal fat tissue volume be used as a predictive factor in foreseeing the response to neoadjuvant chemoradiotherapy in rectum cancer? A CT-based preliminary study.

ABSTRACT

PURPOSE: This study was to investigate the effect of mesorectal fat tissue volume (MRV) on the pathological response to neoadjuvant chemoradiotherapy (nCRT) in patients with locally advanced rectal cancer. METHODS: 88 patients who had been diagnosed with locally advanced rectal cancer between January 2017 and June 2020 were reviewed retrospectively. The total abdominal, subcutaneous, visceral, and mesorectal fatty tissue components were measured semiquantitatively by two radiologists using computed tomography (CT)-based findings. The patients were divided into two groups as those with and without a pathological response to nCRT. The relationship of MRV with the other fat tissue components of the body was also evaluated. RESULTS: We performed a retrospective analysis of 88 patients (mean age 62.7 years [range, 33-90 years]; 31 males and 57 females). A positive response to nCRT was present in 47 patients. There were 59 patients with stage 3 disease. 46 patients demonstrated lymph node involvement. The mean MRV was 69.6 ± 31.0 ml in no-response group and 105.8 ± 47.5 ml in response-positive patients (p < 0.05). MRV showed the highest correlation with visceral fat volume (VFV). There was a negative correlation between the MRV and the N stage. A cut-off value of ≥ 69.4 for MRV predicted the repsonse to nCRT, with 82.9% sensitivity and 58.5% specificity [AUC 0.757 (0.653-0.842), p < 0.001] in receiver operating characteristic (ROC) curve analysis CONCLUSIONS: MRV can be used as a novel parameter in predicting of pathological response to nCRT in locally advanced rectal cancer patients.