Comparison of Three Dimensional Conformal Radiation Therapy, Intensity Modulated Radiation Therapy and Volumetric Modulated Arc Therapy for Low Radiation Exposure of Normal Tissue in Patients with Prostate Cancer

Aydin Cakir,Zuleyha Akgun,Merdan Fayda,Fulya Agaoglu

doi:10.7314/apjcp.2015.16.8.3365

Aydin Cakir, Zuleyha Akgun + Show 2 more

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https://doi.org/10.7314/apjcp.2015.16.8.3365

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Abstract

Radiotherapy has an important role in the treatment of prostate cancer. Three-dimensional conformal radiation therapy (3D-CRT), intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) techniques are all applied for this purpose. However, the risk of secondary radiation-induced bladder cancer is significantly elevated in irradiated patients compared surgery-only or watchful waiting groups. There are also reports of risk of secondary cancer with low doses to normal tissues. This study was designed to compare received volumes of low doses among 3D-CRT, IMRT and VMAT techniques for prostate patients. Ten prostate cancer patients were selected retrospectively for this planning study. Treatment plans were generated using 3D-CRT, IMRT and VMAT techniques. Conformity index (CI), homogenity index (HI), receiving 5 Gy of the volume (V5%), receiving 2 Gy of the volume (V2%), receiving 1 Gy of the volume (V1%) and monitor units (MUs) were compared. This study confirms that VMAT has slightly better CI while thev olume of low doses was higher. VMAT had lower MUs than IMRT. 3D-CRT had the lowest MU, CI and HI. If target coverage and normal tissue sparing are comparable between different treatment techniques, the risk of second malignancy should be a important factor in the selection of treatment.

Highlights

About 50% of all cancer patients in the world receive radiotherapy during their treatment
Because there is almost not control group treated without radiation expect for cancer of prostate and cancer of the cervix, in which surgery is a viable alternative to radiotherapy (Ashman et al, 2005, Luxton et al, 2004)
Many radiation-induced second cancers appear to occur in organs and tissues in the high-dose volume, but some may appear in the low dose volumes

Summary

Introduction

About 50% of all cancer patients in the world receive radiotherapy during their treatment. The aim of radiotherapy is to keep local tumour control and tolerable normal tissue complications for early and late effects (Cahlon et al, 2008; Zelefsky et al, 2008). Hall and Cheng-Shie have expressed by increasing the volume of normal tissue receiving low doses, may increase the incidence of secondary cancer. A linear relation exists between cancer and dose from about 0,1 Sv up to about 2,5 Sv (Hall et al, 2006; NRCP report, 1993). These data represent the gold standard for our knowledge concerning radiation-induced cancer. Because there is almost not control group treated without radiation expect for cancer of prostate and cancer of the cervix, in which surgery is a viable alternative to radiotherapy (Ashman et al, 2005, Luxton et al, 2004)

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