Related Experiment Video
Updated: Feb 17, 2026
Dynamic Contrast Enhanced Magnetic Resonance Imaging of an Orthotopic Pancreatic Cancer Mouse Model
Published on: April 18, 2015
Neoadjuvant volumetric modulated arc therapy in rectal cancer and the correlation of pathological response with
Necla Gurdal1, Merdan Fayda2, Nijat Alishev3
11 Department of Radiation Oncology, Institute of Oncology, Istanbul University, Istanbul - Turkey.
Purpose:
In this prospective observational study, we aimed to report the applicability and tolerability of neoadjuvant volumetric modulated arc therapy with simultaneous integrated boost (SIB-VMAT) and concurrent chemotherapy in patients with locally advanced rectal cancer (LARC), and to evaluate the correlation of pathological response with apparent diffusion coefficient (ADC) measurements on diffusion-weighted magnetic resonance imaging (DW-MRI) and apoptotic markers.
Methods:
The study enrolled 30 patients with T3 to T4 and/or N+ rectal cancer who preoperatively received SIB-VMAT and concurrent chemotherapy. Before and after the neoadjuvant treatment, apoptotic markers including the nucleosomes and cell-free DNA fragments in the serum samples were examined; DNA integrity was assessed by amplifying the ACTB gene; and the ADC measurements on the DW-MRI were analyzed.
Results:
No patients had acute or chronic grade III-IV toxicity. Pathologic complete response (pCR) was achieved in 8 patients (27%), while in 10 patients (33%) near-complete pathological response was obtained. Posttreatment ADC was significantly higher in patients with pCR compared with the others (1.28 vs. 1.10, p = 0.017). ROC curve analysis showed that posttreatment ADC values had a sensitivity of 75% and a specificity of 77.3% for distinguishing the patients with pCR from other responders. On the other hand, posttreatment DNA integrity values were revealed lower than the pretreatment values (p = 0.36). Also, the results revealed an insignificant increase in the posttreatment serum level of nucleosomes (p = 0.72).
Conclusions:
Neoadjuvant SIB-VMAT with concurrent chemotherapy was proved to be a feasible treatment regimen in LARC with tolerable side effects, and improved local control rate and pCR rate.
