BACKGROUND: Neoadjuvant chemoradiotherapy followed by radical surgery has been a common practice for patients with locally advanced rectal cancer, but the response rate varies among patients. This study aimed to develop a ResNet-Vision Transformer based magnetic resonance imaging (MRI)-endoscopy fusion model to precisely predict treatment response and provide personalized treatment. METHODS: In this multicenter study, 366 eligible patients who had undergone neoadjuvant chemoradiotherapy followed by radical surgery at eight Chinese tertiary hospitals between January 2017 and June 2024 were recruited, with 2928 pretreatment colonic endoscopic images and 366 pelvic MRI images. An MRI-endoscopy fusion model was constructed based on the ResNet backbone and Transformer network using pretreatment MRI and endoscopic images. Treatment response was defined as good response or non-good response based on the tumor regression grade. The Delong test and the Hanley-McNeil test were utilized to compare prediction performance among different models and different subgroups, respectively. The predictive performance of the MRI-endoscopy fusion model was comprehensively validated in the test sets and was further compared to that of the single-modal MRI model and single-modal endoscopy model. RESULTS: The MRI-endoscopy fusion model demonstrated favorable prediction performance. In the internal validation set, the area under the curve (AUC) and accuracy were 0.852 (95% confidence interval [CI]: 0.744-0.940) and 0.737 (95% CI: 0.712-0.844), respectively. Moreover, the AUC and accuracy reached 0.769 (95% CI: 0.678-0.861) and 0.729 (95% CI: 0.628-0.821), respectively, in the external test set. In addition, the MRI-endoscopy fusion model outperformed the single-modal MRI model (AUC: 0.692 [95% CI: 0.609-0.783], accuracy: 0.659 [95% CI: 0.565-0.775]) and the single-modal endoscopy model (AUC: 0.720 [95% CI: 0.617-0.823], accuracy: 0.713 [95% CI: 0.612-0.809]) in the external test set. CONCLUSION The MRI-endoscopy fusion model based on ResNet-Vision Transformer achieved favorable performance in predicting treatment response to neoadjuvant chemoradiotherapy and holds tremendous potential for enabling personalized treatment regimens for locally advanced rectal cancer patients.
Humans ; Rectal Neoplasms/diagnostic imaging* ; Magnetic Resonance Imaging/methods* ; Male ; Female ; Middle Aged ; Neoadjuvant Therapy/methods* ; Aged ; Adult ; Chemoradiotherapy/methods* ; Endoscopy/methods* ; Treatment Outcome

Objective To investigate the combined inhibition effect and the potential mechanism of rapamycin (mammalian target of rapamycin inhibitor) and PD98059 (mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK) inhibitor) on mouse colorectal cancer (CRC). Methods S-ICR mice were subcutaneously injected with 20 mg/kg of 1,2-dimethylhydrazine dihydrochloride in the nape for 20 weeks to induce CRC. From the 16th week, the mice were treated with alone or combined injection with 0.25 mg/kg rapamycin and 2.5 mg/kg PD98059. The drugs were administered for 8 weeks. Subsequently, the animals were sacrificed and dissected, the tumor sizes were measured, and the tumors were harvested for pathological assay. Furthermore, the phosphorylation of mTOR, p70S6K, and 4E-BPl proteins was detected by using immunohistoehemistry. Results The mice treated with rapamycin (44. 44 %) or PD 98059 (either alone (38.89%) or combination treatment (6.67%) were significantly less likely to develop cancer compared with mice receiving none of them (77.78%, P<0. 05). The average size of tumors was (6.15±2. 192), (8.85±3. 983), (2.917±0. 191), (16.36±6.855) mm3 respectively (P<0.05).The anti-cancer effect of the combination treatment was substantially significant. The proteins of phospho-mTOR, phospho-p70s6K and phospho-4E-BPl were significantly down-regulated after treatments (all P values < ,0.05). Conclusions Combined treatment was more effective than single-drug treatments of rapamycin or PD98059 alone for the prevention and treatment of mouse CRC. The mTOR signal pathway might be involved in the inhibitory mechanism.