Assesment of clinical significance four dimensional computed tomography simulationa in planning optimal radiation therapy technique for locoregional advanced lung cancer

[С. Ј. Марић]

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Cilj istraživanja je definisanje optimalne tehnike zračenja lokoregionalno uznapredovalog karcinoma pluća komparacijom dozno volumnih parametara za navedene tehnike zračenja : IMRT, VMAT RA (4DCT simulacija) i 3DCRT (CT simulacija). Urađena je klinička opservaciona kohortna studija, u kojoj je analizirano 70 pacijenata(studijska grupa A-VMAT RA, studijska grupa B-IMRT), te urađeni komparativni 3DCRT planovi za obe studijske grupe. Kriterijumi za uključenje: patohistološki potvrđen lokalno uznapredovali karcinom pluća, klinički stadijum: IIIA,IIIB,IIIC. Kriterijumi za isključivanje:Karcinom pluća druge histologije osim nemikrocelularni i mikrocelularni, metastatski karcinom, klinički stadijumi IA,IB,IIA,IIB,IV,IVA,IVB Analiza doznovolumnih parametara organa od rizika(srce,pluća,jednjak,kičmena moždina) IMRT, VMAT RA tehnike (4DCT simulacija) pokazuje dozimetrijsku prednost, vrednosti parametara su bile signifikantno veće kod planova urađenih 3DCRT tehnikom. Dalja evaluacija ukazuje na homogeniju distribuciju radioterapijske doze kod planova urađenih VMAT RA i IMRT u komparaciji sa 3DCRT tehnikom. Postoji statistički signifikantna redukcija planiranog ciljnog volumena kod tehnika IMRT i VMAT RA u odnosu na klasičnu CT simulaciju i 3DCRT tehniku. Statistički značajno veće vrednosti V20 i MLD –organa od rizika pluća kao i maksimalne doze na organ od rizika kičmena moždina u studijskoj grupi planiranoj IMRT tehnikom, ukazuju na potencijalni benefit VMAT RA tehnike. Komparacija akutnih i hroničnih neželjenih efekata na organ od rizika pluća i jednjak pokazuje da nema statistički značajne razlike između IMRT i VMAT RA tehnike Na osnovu rezultata naše studije možemo zaključiti da IMRT i VMAT RA, tehnike bazirane na 4DCT simulaciji predstavljaju optimalan izbor u radioterapiji lokalno uznapredovalog karcinoma pluća u odnosu na 3DCRT tehniku i klasičnu CT simulaciju.

The aim of this study is to define optimal radiation technique of locoregionally advanced lung cancer by comparing dose-volume parameters for radiation techniques: IMRT, VMAT RA (4DCT simulation) and 3DCRT (CT simulation). This is cinical observational cohort study in which we analyzed 70 patients (study group A-VMAT RA technique, study group B-IMRT). Comparative 3DCRT plans for both study groups were also made.Inclusion criteria: Patients diagnosed and pathohistologically confirmed as locally advanced lung cancer, patients who belong to clinical groups: IIIA, IIIB, and IIIC. Exclusion criteria: Lung cancer of histology other than nonmicrocellular and microcellular, metastatic cancer, clinical stages IA, IB, IIA, IIB, IV, IVA, IVB. In this study, analysis dose volume parameters organs at risk (lungs, oesophagus, heart and spinal cord) IMRT, VMAT RA (4DCT) simulation present dosimetric advantage compared with 3DCRT technique, the values of parameters were significantly higher in 3DCRT technique plans. Further evaluation indicate a more homogeneous distribution of radiotherapy dose on 4D CT based VMAT RA, IMRT techniques plans compared to 3DCRT technique. There was statistically significant reduction of planning target volume in 4D CT based IMRT and VMAT RA plans compared to 3DCRT plans. Statistically significantly higher values of V20 and MLD, maximal dose to the organ of risk spinal cord in the study group planned by IMRT technique compared with VMAT RA, indicates the potential benefit of VMAT RA technique. There was no statistical significant difference between IMRT and VMAT RA study group when comparation of acute and late toxicity (lung and oesophagus) was done. Based on this results, IMRT and VMAT RA, techniques based on 4DCT simulation represent the optimal choice in radiotherapy of locally advanced lung cancer compared to 3DCRT technique and classical CT simulation.

karcinom pluća, 4DCT simulacija, IMRT,VMAT RA, ciljni volumeni

lung cancer, 4D CT simulation, IMRT, VMAT RA, target volumes

616.24.006.6

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