Abstract
PurposeDistant metastasis is the main cause of treatment failure in locally advanced rectal cancer (LARC) patients, despite the recent improvement in treatment strategies. This study aims to evaluate the “delta radiomics” approach in patients undergoing neoadjuvant chemoradiotherapy (nCRT) treated with 0.35-T magnetic resonance-guided radiotherapy (MRgRT), developing a logistic regression model able to predict 2-year disease-free-survival (2yDFS).MethodsPatients affected by LARC were enrolled in this multi-institutional study. A predictive model of 2yDFS was developed taking into account both clinical and radiomics variables. Gross tumour volume (GTV) was delineated on the magnetic resonance (MR) images acquired during MRgRT, and 1,067 radiomic features (RF) were extracted using the MODDICOM platform. The performance of RF in predicting 2yDFS was investigated in terms of the Wilcoxon–Mann–Whitney test and area under receiver operating characteristic (ROC) curve (AUC).Results48 patients have been retrospectively enrolled, with 8 patients (16.7%) developing distant metastases at the 2-year follow-up. A total of 1,099 variables (1,067 RF and 32 clinical variables) were evaluated in two different models: radiomics and radiomics/clinical. The best-performing 2yDFS predictive model was a delta radiomics one, based on the variation in terms of area/surface ratio between biologically effective doses (BED) at 54 Gy and simulation (AUC of 0.92).ConclusionsThe results of this study suggest a promising role of delta radiomics analysis on 0.35-T MR images in predicting 2yDFS for LARC patients. Further analyses including larger cohorts of patients and an external validation are needed to confirm these preliminary results.
Highlights
Neoadjuvant concurrent chemoradiotherapy or short-course radiotherapy followed by surgery with total mesorectal excision (TME) is considered the standard treatment for locally advanced rectal cancer (LARC) [3, 4]
This treatment approach has led to a significant reduction in local recurrence (LR) [5, 6], a significant improvement in terms of disease-free survival (DFS) or overall survival (OS) was not demonstrated according to the results of several trials focused on this outcome [7,8,9]
Despite the improvements in treatment strategies achieved in recent years, distant metastases (DMs) are still the main cause of treatment failure and mortality in LARC patients [10, 11]
Summary
Colorectal cancer (CRC) is one of the most common tumors worldwide and the second most common cause of cancer death in the United States [1].Rectal cancer represents one-third of all CRCs, with the second highest incidence and second leading cause of cancer death in Western society [2].Neoadjuvant concurrent chemoradiotherapy (nCRT) or short-course radiotherapy followed by surgery with total mesorectal excision (TME) is considered the standard treatment for locally advanced rectal cancer (LARC) [3, 4].This treatment approach has led to a significant reduction in local recurrence (LR) [5, 6], a significant improvement in terms of disease-free survival (DFS) or overall survival (OS) was not demonstrated according to the results of several trials focused on this outcome [7,8,9].Despite the improvements in treatment strategies achieved in recent years, distant metastases (DMs) are still the main cause of treatment failure and mortality in LARC patients [10, 11].Disease-free survival has been used as primary endpoint in numerous trials and represents one of the most promising primary clinical endpoints for patient risk stratification [12]. Neoadjuvant concurrent chemoradiotherapy (nCRT) or short-course radiotherapy followed by surgery with total mesorectal excision (TME) is considered the standard treatment for locally advanced rectal cancer (LARC) [3, 4]. This treatment approach has led to a significant reduction in local recurrence (LR) [5, 6], a significant improvement in terms of disease-free survival (DFS) or overall survival (OS) was not demonstrated according to the results of several trials focused on this outcome [7,8,9].
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