Neoadjuvant volumetric modulated arc therapy in rectal cancer and the correlation of pathological response with diffusion-weighted MRI and apoptotic markers. Issue 4 (August 2018)

• Record Type: Journal Article
• Authors: Gurdal, Necla; Fayda, Merdan; Alishev, Nijat; Bakir, Baris; Tastekin, Didem; Aykan, Faruk; Gezer, Ugur; Balik, Emre; Saglam, Esra Kaytan; Oral, Ethem Nezih; Gulluoglu, Mine; Kizir, Ahmet
• Is Part Of: Tumori. Volume 104:Issue 4(2018)
• Page Start: 266
• Page End: 272
• Publication Date: 2018-08
• Subjects: Apoptotic markers -- Diffusion-weighted MRI -- Nucleosomes -- Pathologic complete response -- Rectal carcinoma -- Volumetric modulated arc therapy-simultaneous integrated boost (SIB-VMAT); Cancer -- Periodicals; 616.994
• DOI: 10.5301/tj.5000702
• Languages: English
• ISSNs: 0300-8916

Abstract

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.