Pre-Treatment T2-WI Based Radiomics Features for Prediction of Locally Advanced Rectal Cancer Non-Response to Neoadjuvant Chemoradiotherapy: A Preliminary Study.

Bianca Petresc,Andrei Lebovici,Diana Sorina Feier,Cosmin Caraiani,Florin Graur,Mircea Marian Buruian

doi:10.3390/cancers12071894

Abstract

Locally advanced rectal cancer (LARC) response to neoadjuvant chemoradiotherapy (nCRT) is very heterogeneous and up to 30% of patients are considered non-responders, presenting no tumor regression after nCRT. This study aimed to determine the ability of pre-treatment T2-weighted based radiomics features to predict LARC non-responders. A total of 67 LARC patients who underwent a pre-treatment MRI followed by nCRT and total mesorectal excision were assigned into training (n = 44) and validation (n = 23) groups. In both datasets, the patients were categorized according to the Ryan tumor regression grade (TRG) system into non-responders (TRG = 3) and responders (TRG 1 and 2). We extracted 960 radiomic features/patient from pre-treatment T2-weighted images. After a three-step feature selection process, including LASSO regression analysis, we built a radiomics score with seven radiomics features. This score was significantly higher among non-responders in both training and validation sets (p < 0.001 and p = 0.03) and it showed good predictive performance for LARC non-response, achieving an area under the curve (AUC) = 0.94 (95% CI: 0.82–0.99) in the training set and AUC = 0.80 (95% CI: 0.58–0.94) in the validation group. The multivariate analysis identified the radiomics score as an independent predictor for the tumor non-response (OR = 6.52, 95% CI: 1.87–22.72). Our results indicate that MRI radiomics features could be considered as potential imaging biomarkers for early prediction of LARC non-response to neoadjuvant treatment.

Highlights

Colorectal cancer is the third most common cancer worldwide and the second leading cause of oncologic-related mortality around the globe [1]
17 patients were classified according to the tumor regression grade (TRG) as non-responders (NR) having TRG = 3, while the remaining 27 were classified as responders (R), 5 of them having
Tumor length, tumor differentiation grade and mesorectal fascia involvement (MRF) were significantly different among non-responders versus responders, this was not confirmed in the validation dataset

Summary

Introduction

Colorectal cancer is the third most common cancer worldwide and the second leading cause of oncologic-related mortality around the globe [1]. Rectal cancers account for approximately 30% of the total cases of colorectal malignancies [2]. The standard-of-care treatment for patients with locally advanced rectal cancer (LARC) is neoadjuvant chemotherapy (nCRT) followed by total mesorectal excision (TME) [3,4,5]. The percentage of patients who do not achieve tumor regression after nCRT, defined as non-responders (NR), is reported to be between 7 and 30% [11,12,13,14,15]. The potential side effects of nCRT can be very serious such as hematologic, gastrointestinal or dermatologic effects, incontinence or sexual dysfunction [15,16,17,18,19] and 14–27% of patients with LARC who received this regimen developed acute or long-term grade 3–4 toxic effects as reported by Sauer et al [20]. Prediction of NR before the beginning of neoadjuvant therapy could be of great value in order to avoid ineffective treatment and to develop a more tailored strategy of care such as a primary surgical intervention or an intensified treatment regimen

Objectives

Methods

Results

Conclusion