MRI delta radiomics during chemoradiotherapy for prognostication in locally advanced cervical cancer

Effective diagnostic tools for prompt identification of high-risk locally advanced cervical cancer (LACC) patients are needed to facilitate early, individualized treatment. The aim of this work was to assess temporal changes in tumor radiomics (delta radiomics) from T2-weighted imaging (T2WI) during concurrent chemoradiotherapy (CCRT) in LACC patients, and their association with progression-free survival (PFS). Furthermore, to develop, validate, and compare delta- and pretreatment radiomic signatures for prognostic modeling.

A total of 110 LACC patients undergoing CCRT with MRI at baseline and mid-treatment were divided into training (cohort_T: n = 73) and validation (cohort_V: n = 37) cohorts. Radiomic features were extracted from tumors segmented on pre-CCRT and mid-CCRT T2WI and radiomic deltas (delta features) were computed. Two radiomic signatures for predicting PFS were constructed by least absolute shrinkage and selection operator (LASSO) Cox regression: Delta_rad (from delta features) and Pre-CCRT_rad (from pre-CCRT features). Prognostic performance of the radiomic signatures, 2018 International Federation of Gynecology and Obstetrics (FIGO) stage (I-IV), and baseline MRI-derived maximum tumor diameter (Tumor_max: ≤2 cm; >2 and ≤ 4 cm; >4 cm) was evaluated by area under time-dependent receiver operating characteristics (tdROC) curves (AUC) in cohort_T and cohort_V (AUC_T/AUC_V). Mann-Whitney U tests assessed differences in radiomic delta features. PFS was evaluated using the Kaplan-Meier method with log-rank tests.

Delta_rad (AUC_T/AUC_V: 0.74/0.79) marginally outperformed Pre-CCRT_rad (0.72/0.75) for predicting 5-year PFS, and both signatures clearly surpassed that of FIGO (0.61/0.61) and Tumor_max (0.58/0.65). In total, four features within Delta_rad and Pre-CCRT_rad significantly differed in delta feature values between progressors and non-progressors, being consistently lower in progressors (p ≤ 0.03 for all). High Delta_rad and Pre-CCRT_rad radiomic scores were associated with poor PFS (p ≤ 0.04 for Delta_rad in cohort_T/Pre-CCRT_rad in both cohorts; p = 0.11 for Delta_rad in cohort_V).

Delta- and pretreatment radiomic signatures equally allow early prognostication in LACC, outperforming FIGO stage and MRI-assessed maximum tumor diameter.