Procena odgovora karcinoma rektuma na neoadjuvantnu hemioradioterapiju metodom magnetne rezonance i difuzionog imidžinga

Abstract

Cilj: Neoadjuvantna hemioradioterapija (CRT) danas predstavlja standardni terapijski modalitet kod bolesnika sa lokalno uznapredovalim karcinomom rektuma jer dovodi do preoperativnog smanjenja tumorskog volumena i sniženja gradusa tumora, a u kombinaciji sa totalnom mezorektalnom ekscizijom, kao standardnom hirurškom opcijom za karcinom rektuma, i do sniženja stope lokalnog recidiva i produženja preživljavanja kod bolesnika sa karcinomom rektuma. Glavni ciljevi ove studije bili su da se odredi dijagnostička preciznost magnetne rezonance i difuzionog imidžinga u kvalitativnoj proceni stepena odgovora karcinoma rektuma na neoadjuvantnu terapiju, u kvalitativnoj proceni tumorske zahvaćenosti cirkumferentne resekcione margine i u kvantitativnoj proceni stepena odgovora karcinoma rektuma na preoperativnu hemioradioterapiju. Metodologija: Retrospektivnom kliničkom studijom obuhvaćeno je 62 bolesnika sa lokalno uznapredovalim karcinomom rektuma lečenih neoadjuvantnom hemioradioterapijom kojima je u inicijalnoj fazi i 6-8 nedelja nakon završetka neoadjuvantnog tretmana urađen MRI sa DWI radi procene stadijuma tumorske bolesti i procene tumorskog odgovora na primenjenu terapiju. Istraživanje je sprovedeno u Centru za radiologiju i magnetnu rezonancu Kliničkog centra Srbije u periodu od januara 2010. do juna 2013. Patološka analiza rađena je u Službi za patohistologiju Kliničkog centra Srbije na Odeljenju za Digestivnu patologiju. Istraživanje je odobreno od strane Etičkog komiteta Medicinskog fakulteta u Beogradu. Inicijalni i postterapijski MR pregled rađeni su po identičnom protokolu, pri čemu je procenjivan tumorski gradus pre i nakon CRT, tumorska infiltracija mezorektalne fascije nakon hemioradioterapije i tumorski odgovor na primenjenu terapiju metodom magnetne rezonance i difuzionog imidžinga na kvalitativan i kvantitativan način, kvalitativnom analizom MR i DWI slike i merenjem ADC vrednosti tumorskog tkiva pre i posle hemioradioterapije primenom tri različita ROI merna metoda. Histopatološka analiza rektalnih resekata vršena je procenom stepena tumorske regresije nakon neoadjuvantne terapije korišćenjem histopatološke skale za regresiju tumora (tumor regression grade – TRG) po Mandard-u i služila je kao referentni standard...

Objective: Neoadjuvant long course combined chemoradiotherapy (CRT), as a first step of a standard treatment for patients with locally advanced rectal cancer, aims to induce tumor downsizing and downstaging before surgery, and in combination with total mesorectal excision, the standard surgical option for rectal cancer, leads to decrease of local recurrence rates and increase of survival in patients with rectal cancer. The main purpose of this study was to assess diagnostic accuracy of magnetic resonance imaging and diffusion-weighted imaging in response evaluation of rectal cancer to neoadjuvant therapy and in prediction of tumor clearance from circumferential resection margin and to estimate diagnostic accuracy of diffusion-weighted imaging in quantitative assessment of tumor response to neoadjuvant therapy. Methodology: This retrospective clinical study analyzed 62 patients with locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy. In all patients pretreatment MRI and posttreatment MRI (6 to 8 weeks after completion of neoadjuvant therapy) were preformed for assessment tumor stage before and after CRT and for estimation tumor response to therapy. The study was conducted at the Center for radiology and magnetic resonance imaging of Clinical Centre of Serbia from January 2010 to June 2013. Histopathological analysis was performed at the Department for histopathology (Department for Digestive Pathology). The study was approved by the Ethics Committee of Medical Faculty University of Belgrade. Pre- and post-CRT MRI were performed on the same way in order to stage and restage rectal cancer after CRT, to estimate tumor clearance from mesorectal fascia after neoadjuvant chemoradiotherapy and to evaluate tumor response to applied therapy qualitatively and quantitatively by methods of magnetic resonance imaging and diffusion-weighted imaging, by qualitative analysis MR and DWI images and by measuring tumor ADC values before and after CRT with three different ROI positioning methods. Histopathological analysis of rectal specimens with assessment of tumor regression grade (TRG) according to Mandard served as standard of reference...