Delta Radiomics Can Predict Distant Metastasis in Locally Advanced Rectal Cancer: The Challenge to Personalize the Cure.

Giuditta Chiloiro,Maria Antonietta Gambacorta,Brunella Barbaro,Davide Cusumano,Elisa Meldolesi,Andrea Damiani,Vincenzo Valentini,Luca Boldrini,Carlotta Masciocchi,Riccardo Manfredi,Nicola Dinapoli,Pablo Rodriguez-Carnero,Calogero Casà,Jacopo Lenkowicz,Davide Carano

doi:10.3389/fonc.2020.595012

Abstract

PurposeDistant metastases are currently the main cause of treatment failure in locally advanced rectal cancer (LARC) patients. The aim of this research is to investigate a correlation between the variation of radiomics features using pre- and post-neoadjuvant chemoradiation (nCRT) magnetic resonance imaging (MRI) with 2 years distant metastasis (2yDM) rate in LARC patients.Methods and MaterialsDiagnostic pre- and post- nCRT MRI of LARC patients, treated in a single institution from May 2008 to June 2015 with an adequate follow-up time, were retrospectively collected. Gross tumor volumes (GTV) were contoured by an abdominal radiologist and blindly reviewed by a radiation oncologist expert in rectal cancer. The dataset was firstly randomly split into 90% training data, for features selection, and 10% testing data, for the validation. The final set of features after the selection was used to train 15 different classifiers using accuracy as target metric. The models’ performance was then assessed on the testing data and the best performing classifier was then selected, maximising the confusion matrix balanced accuracy (BA).ResultsData regarding 213 LARC patients (36% female, 64% male) were collected. Overall 2yDM was 17%. A total of 2,606 features extracted from the pre- and post- nCRT GTV were tested and 4 features were selected after features selection process. Among the 15 tested classifiers, logistic regression proved to be the best performing one with a testing set BA, sensitivity and specificity of 78.5%, 71.4% and 85.7%, respectively.ConclusionsThis study supports a possible role of delta radiomics in predicting following occurrence of distant metastasis. Further studies including a consistent external validation are needed to confirm these results and allows to translate radiomics model in clinical practice. Future integration with clinical and molecular data will be mandatory to fully personalized treatment and follow-up approaches.

Highlights

Colorectal cancer is the third most incident malignancy and the fourth in cancer-related death, being more prevalent in regions with high human developmental index [1].The standard treatment of locally advanced rectal cancers (LARC) is neoadjuvant chemoradiotherapy followed by surgery with total mesorectal excision (TME) [2, 3].The combination of nCRT and surgery has improved local control (LC) of the disease in LARC patients, but it does not affect the disease-free (DFS) and overall survivals (OS) [3].Recurrence in the form of distant metastases is the main cause of treatment failure and near 25% of treated LARC patients develop metastases in 5 years [4, 5]
The purpose of this study is to assess the ability of the delta radiomics approach in predicting 2yDM in LARC, combining radiomics features extracted from staging and post-treatment Magnetic resonance imaging (MRI) [24, 27]
We retrospectively and consecutively selected patients from our institution, a national reference centre for rectal cancer treatment, between May 2008 and June 2015, who met the following inclusion criteria: (a) patients older than 18 years old; (b) with pathologically proven rectal adenocarcinoma; (c) clinical stage T3-4 N0, T1-4 N1-2 or with mesorectal fascia involvement (MRF+) according to the AJCC TNM 7th edition; (d) nCRT followed by surgery at our centre; (e) with both pre-treatment and post-treatment MRI performed in our institution; (f) maximum intervals of 3 months between the end of nCRT and posttreatment MRI [14]; (g) clinical and imaging follow-up of at least 3 years from surgery

Summary

Introduction

Colorectal cancer is the third most incident malignancy and the fourth in cancer-related death, being more prevalent in regions with high human developmental index [1].The standard treatment of locally advanced rectal cancers (LARC) is neoadjuvant chemoradiotherapy (nCRT) followed by surgery with total mesorectal excision (TME) [2, 3].The combination of nCRT and surgery has improved local control (LC) of the disease in LARC patients, but it does not affect the disease-free (DFS) and overall survivals (OS) [3].Recurrence in the form of distant metastases (mainly affecting the liver) is the main cause of treatment failure and near 25% of treated LARC patients develop metastases in 5 years [4, 5]. The standard treatment of locally advanced rectal cancers (LARC) is neoadjuvant chemoradiotherapy (nCRT) followed by surgery with total mesorectal excision (TME) [2, 3]. The combination of nCRT and surgery has improved local control (LC) of the disease in LARC patients, but it does not affect the disease-free (DFS) and overall survivals (OS) [3]. Recurrence in the form of distant metastases (mainly affecting the liver) is the main cause of treatment failure and near 25% of treated LARC patients develop metastases in 5 years [4, 5]. Identification of patients with higher risk of developing distant metastasis within 2 years (2yDM) represents a topic of great interest for the clinical community, as it could allow a more accurate personalized management, defining more strict clinical and imaging vigilance or even proposing more intensive treatments

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