Home About us Editorial board Ahead of print Current issue Search Archives Submit article Instructions Subscribe Contacts Login 

 Table of Contents  
ORIGINAL ARTICLE
Year : 2021  |  Volume : 17  |  Issue : 1  |  Page : 80-87

Dosimetric comparison of single-arc/partial-arc volumetric modulated arc therapy and intensity-modulated radiotherapy for peripheral and central lung cancer


Department of Radiation Oncology, Medical Faculty of Osmangazi University, Eskisehir, Turkey

Date of Submission31-Mar-2019
Date of Decision19-May-2019
Date of Acceptance18-Oct-2019
Date of Web Publication19-Oct-2020

Correspondence Address:
Melek Akcay
Department of Radiation Oncology, Medical Faculty of Osmangazi University, Odunpazari Eskisehir
Turkey
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jcrt.JCRT_221_19

Rights and Permissions
 > Abstract 


Aim: The aim of this study is to compare the differences between intensity-modulated radiotherapy (IMRT) and single-arc/partial-arc volumetric modulated arc therapy (SA/PA-VMAT) techniques in locally advanced-stage non-small cell lung cancer (NSCLC).
Materials and Methods: Locally advanced 22 patients with NSCLC were evaluated retrospectively. Each patient underwent radiation therapy with either IMRT or SA-VMAT or 2PA-VMAT technique. Homogeneity index, conformity number, and dosimetric parameters were evaluated.
Results: Ten peripheral and 12 central lung tumors were evaluated. In the entire patient group, tV5-10-60, total mean lung dose (tMLD), iV5-10-30-50-60, iMLD, and esophagus Dmean and Dmax were lower in IMRT technique, cV5-10-20-30, kMLD, and medulla spinalis Dmax were lower in PA-VMAT technique, whereas iMLD is the highest in the SA-VMAT technique. In peripheral tumors, tV5-10-60, iV5-10-20-30-40-60, iMLD, and esophagus Dmean were lower in IMRT technique and kV5-10 was lower in the 2PA-VMAT technique. In central tumors, tV5-10, tMLD, iV5-60, iMLD, and esophagus Dmean and Dmax were lower in IMRT technique, whereas cV10-20 and medulla spinalis Dmax were lower in 2PA-VMAT, and all contralateral lung doses are high in the SA-VMAT technique (all P < 0.05).
Conclusion: IMRT and VMAT techniques have different advantages in locally advanced lung cancer, and the use of those two techniques as a hybrid can provide a single collection of these advantages.

Keywords: Central lung cancer, dosimetry, intensity-modulated radiotherapy, peripheral lung cancer, volumetric modulated arc therapy


How to cite this article:
Akcay M, Etiz D, Duruer K, Bozdogan O, Ozen A. Dosimetric comparison of single-arc/partial-arc volumetric modulated arc therapy and intensity-modulated radiotherapy for peripheral and central lung cancer. J Can Res Ther 2021;17:80-7

How to cite this URL:
Akcay M, Etiz D, Duruer K, Bozdogan O, Ozen A. Dosimetric comparison of single-arc/partial-arc volumetric modulated arc therapy and intensity-modulated radiotherapy for peripheral and central lung cancer. J Can Res Ther [serial online] 2021 [cited 2021 Nov 28];17:80-7. Available from: https://www.cancerjournal.net/text.asp?2021/17/1/80/298615




 > Introduction Top


Radiotherapy (RT) plays a very important role in the treatment of non-small cell lung cancer (NSCLC). In recent years, more modern radiation techniques have emerged with the development of RT equipment and radiation physics. It is important to choose the most appropriate RT technique for patients with NSCLC. Intensity-modulated RT (IMRT) in combination with image-guided RT (IGRT) resulted in excellent clinical outcomes.[1] Although IMRT increases the dose conformity, it requires longer treatment time. Volumetric modulated arc therapy (VMAT) significantly improved treatment time.[2] Many studies have shown that VMAT technique provides high-level conformal dose distribution, decreases risky organ doses, and shortens the duration of treatment than IMRT.[3] The long duration of treatment in IMRT may improve patient discomfort during treatment, and the increased monitor units (MUs) could lead to increased incidence of radiation-related secondary cancers.[4],[5] However, the low-dose lung volume (V5 and V10) increases with the VMAT technique.[6] Dose-volume histogram (DVH) parameters V5 and V10 have been shown to be the predictors of radiation pneumonitis (RP).[7]

Although all modern RT techniques provide appropriate dose distribution and reduce the risk of organ damage, there is still no consensus on optimal RT technique in NSCLC. In this dosimetric study, patients with NSCLC were treated with conventional fractionated RT.

The aim of the present study was to compare IMRT and single-arc (SA)/2 partial-arc (PA)-VMAT in irradiation of peripheral and central lung tumors. Furthermore, target volume coverage, organs at risk doses, and treatment duration were also compared.


 > Materials and Methods Top


Patient selection

The study included 22 NSCLC patients, i.e., 10 with peripheral NSCLC and 12 with central NSCLC. All underwent radical RT ± chemotherapy (CT) in the Radiation Oncology Department of Eskişehir Osmangazi University Medical Faculty between 2016 and 2018. All diagnoses were confirmed histopathologically. Patients with peripheral and central lung cancer were randomly selected. All patients were staged according to the 8th edition staging system of the American Joint Committee on Cancer.[7]

Target volume delineation and organs at risk

The patients were immobilized in the supine position with their arms raised above the head on a lung board (T-bar/Wingboard) specifically designed for lung treatments. A 5-mm slice thickness of images between the cricoid cartilage and the upper limit of the L2 vertebra was performed with the Siemens Somatom Definition AS® CT device. Central tumors included bronchial tumor/perihilar masses. There was no elective nodal irradiation (ENI), and involved-field radiation therapy (IFRT) was used.

Primary lung tumor and lymph nodes with CT axis ≥1 cm or hypermetabolic in positron emission tomography– Computed tomography (CT) are contoured as gross tumor volume (GTV). Clinical target volume (CTV) typically encompasses the GTV plus 0.6–0.8 cm margin for tumor and 0.5 cm for affected lymph nodes. For the planning target volume (PTV), a 0.5-cm margin was added to the CTV. All contours were contoured together by three radiation oncologists.

Lungs, heart, esophagus, and medulla spinalis were contoured. Normal lung was formed by removal of GTV after both lungs were contoured. The planning organ at risk volume was extended as 5 mm to the spinal cord. The limits for the organs at risk in the present study are listed in [Table 1]. All generated plans for each patient consisted of 60 Gy to be delivered to PTV in 30 fractions. The planning was made to give at least 95% of PTV with a dose range not exceeding −5% and +5% of the prescribed dose. These plans were made by two physicists. Patients were treated with Varian Trilogy® linear accelerator.
Table 1: Dose limits of organs at risk

Click here to view


Treatment plan

All patients underwent radiation therapy with either IMRT or SA-VMAT or PA-VMAT technique. All plans were calculated using the AAA algorithm in the Eclipse planning system (Version 13.0.26, Varian Medical Systems, Palo Alto, CA, USA), and 6 MV photon energy was chosen in all plans.

Intensity-modulated radiotherapy

Dynamic IMRT was used. For each plan, 5 or 7 coplanar beams at different angles were used depending on the tumor location, tumor dose coverage, and organs at risk (5 coplanar beams in 11 patients and 7 coplanar beams in 11 patients). Sliding window method was used in all plans. There was no limitation on the total number of segments, the number of iterations, and the minimum MU per segment. For each plan, 115 and 145 segments were used on 5 and 7 coplanar beams, respectively.

Single-arc volumetric modulated arc therapy

The SA-VMAT technique used a 360° single arc consisting of 178 control points. The rotation direction of the gantry was selected clockwise (CW). The starting angle was 181° and the ending angle was 179°. The collimator angle was chosen as 30° to reduce leakage radiation and tongue and groove effect in all plans. The gantry rotation rate was chosen to be a maximum of 4.8°/s with a dose rate of maximum 600 MU/min. These values were automatically set at gantry rotation.

Partial-arc volumetric modulated arc therapy

In PA-VMAT technique, two half arcs of 180° each consisting of 98 control points were used. Partial arcs were adjusted CW or counterclockwise according to the location of the tumor, and the starting angle of CW arc was 0°–10° and the end angle was 180°–190°. On the other hand, the starting angle of counterclockwise arc was 0°–350° and the end angle was 180°–170°. The collimator angle was chosen to be 30° in CW direction and 330° counterclockwise to reduce leakage radiation and tongue and groove effect in all plans. The gantry rotation rate was chosen to be a maximum of 4.8°/s with a dose rate of maximum 600 MU/min. These values were automatically set at gantry rotation.

Evaluation of dose-volume histogram

DVH for PTV, normal lung, ipsilateral lung, heart, medulla spinalis, and esophagus was examined in each technique. To determine the accuracy of the dose distribution on PTV, homogeneity index (HI)[8] and conformation number conformation number (CN).

HI is defined as in the followed:[8]



D2% is defined as the maximum dose given to 2% of the target volume. D98% is defined as the minimum dose given to 98% of the target volume, and D50% is defined as the median absorbed dose given to 50% of the target volume.[10]

CN is calculated as in the followed:[9]



TVRI is the target volume covered by the reference isodose. TV is the target volume and VRI is the volume covered by the reference isodose.

The CN value is between 0 and 1, with 1 as an ideal value. A HI value equal to 0 is an almost homogeneous dose distribution. Large HI values indicate higher doses than the defined dose and/or a large volume in the target receives a low dose.[10]

Statistical analysis

The analyses were performed using SPSS for Windows 21.0 (IBM Corp. Released 2013. IBM SPSS Statistics for Windows, Version 22.0. Armonk, NY, USA: IBM Corp.). The Shapiro–Wilk test was used to investigate the appropriateness of the data to normal distribution. Nonparametric Friedman test was used in the comparison between planning groups, and Post hoc tests were used to determine different groups. Data were summarized as mean ± standard deviation or median (Q1; Q3). P <0.05 was considered statistically significant.


 > Results Top


A total of 22 locally advanced-stage lung cancer patients were evaluated. IMRT, SA-VMAT, and 2PA-VMAT were planned for each patient. Patient and tumor characteristics are summarized in [Table 2]. Isodose curves from all three plans of each patient with central tumor are shown in [Figure 1] and with peripheral tumor in [Figure 2] in transverse sections.
Table 2: Patient and tumor characteristics

Click here to view
Figure 1: Isodose distribution of central tumor: (a) Intensity-modulated radiotherapy, (b) single-arc volumetric modulated arc therapy, (c) 2 partial-arc volumetric modulated arc therapy

Click here to view
Figure 2: Isodose distribution of peripheral tumor: (a) Intensity-modulated radiotherapy, (b) single-arc volumetric modulated arc therapy, (c) 2 partial-arc volumetric modulated arc therapy

Click here to view


Organs at risk results in all patients

[Table 3] summarizes IMRT and VMAT DVHs in all patients. For the whole lung, in the IMRT plan, tV5 (38.7% vs. 40.1% and 43.1%), tV10 (22.6% vs. 24.1% and 30.5%), tV60 (0.2% vs. 0.6% and 0.5%), and tMLD (8.5 vs. 8.8 and 10.2 Gy) were the lowest compared to the 2PA-VMAT and SA-VMAT plans. For the ipsilateral lung, in the IMRT plan, iV5 (45.1% vs. 48.9% and 47.3%), iV10 (36.9% vs. 38.9% and 40.9%), iV30 (16.8% vs. 17.4% and 20.0%), iV50 (6.6% vs. 7.0% and 7.5%), and iV60 (0.2% vs. 1.3% and 1.4%) were lower compared to 2PA-VMAT and SA-VMAT plans. While there was no statistical difference between iV40 and iMLD in the IMRT and SA-VMAT plans, iV40 (12.1% vs. 10.5% and 10.8%) and iMLD (14.6 vs. 13.2 and 13.6 Gy) were higher in the 2PA-VMAT plans. In the contralateral lung, cV5 (32.4% vs. 33.3% and 38.4%), cV10 (10.8% vs. 11.6% and 23.3%), cV20 (0.7% vs. 2.4% and 3.2%), cV30 (0.1% vs. 1.1% and 0.3%), and cMLD (4 vs. 4.2 and 5.5 Gy) were lower in the 2PA-VMAT plans compared to IMRT and SA-VMAT plans. Medulla spinalis Dmax (maximum dose) (26.7 vs. 29.5 and 32.7 Gy) were lower in 2PA-VMAT plans than IMRT and SA-VMAT plans. Esophagus Dmean (mean dose) (10.3 vs. 11.9 and 10.6 Gy) and esophagus Dmax (40.0 vs. 43.9 and 42.5 Gy) were lower in IMRT plans than SA-VMAT and 2PA-VMAT plans.
Table 3: Dose-volume histogram in all patients

Click here to view


These results suggest that the ipsilateral lung, total lung, and esophagus are better preserved with IMRT, whereas the contralateral lung and medulla spinalis are better preserved with 2PA-VMAT technique.

Organs at risk results in patients with peripheral tumor

[Table 4] summarizes IMRT and VMAT DVHs in peripheral lung cancer. For the whole lung, in the IMRT technique, compared to the SA-VMAT and 2PA-VMAT techniques, tV5 (25.8% vs. 31.1% and 27.2%), tV10 (13.3% vs. 19.3% and 15.9%), and tV60 (0% vs. 0.3% and 0.5%) were lower. In the ipsilateral lung, iV5 (33.9% vs. 35% and 37.9%), iV10 (24.3% vs. 27.6% and 29.9%), iV20 (16.7% vs. 18% and 20%, 6), iV30 (10.4% vs. 11.7% and 13.6%), iV40 (7% vs. 7.7% and 9%), iV60 (0.1% vs. 0.7% and 1.1%), and iMLD (9.1 vs. 9.8 and 10.8 Gy) were lower in IMRT plans than SA-VMAT and 2PA-VMAT. In contralateral lung, cV5 (16.8% vs. 21.6% and 27.1%) and cV10 (3.0% vs. 5.8% and 10.2%) were lower in the 2PA-VMAT than IMRT and SA-VMAT. Esophagus Dmean (6 vs. 6.5 and 7.5 Gy) was lower in IMRT than SA-VMAT and 2PA-VMAT.
Table 4: Dose-volume histogram in peripheral tumors

Click here to view


In the peripheral tumors, total lung, ipsilateral lung, and esophagus were better preserved by IMRT technique, whereas the contralateral lung was better protected by 2PA-VMAT technique.

Organs at risk results in patients with central tumor

In [Table 5], IMRT and VMAT DVHs are summarized in central lung cancer. For the whole lung, in the IMRT plans, tV5 (49.4% vs. 50.9% and 52.9%), tV10 (30.3% vs. 31% and 39.9%), and tMLD (10.3 vs. 10.8 vs. 13.1 Gy) were the lowest, while they were found to be the highest in the SA-VMAT plans. For ipsilateral lung, iV5 (54.5% vs. 57% and 58%), iV60 (0.3% vs. 1.8% and 1.6%), and iMLD (16.6 vs. 16.8 and 17.8 Gy) were found to be the lowest in IMRT plans. iV20 (35.5% vs. 36.5% and 39.5%) was lower in the SA-VMAT technique compared to other techniques, whereas iV30 (25.3% vs. 22.1% and 22.5%) in 2PA-VMAT technique was higher than that. In contralateral lung doses, kV5 (43% vs. 47.8% and 45.4%) was lower in the IMRT technique, whereas kV10 (15.9% vs. 32.9%) and kV20 (1.4% vs. 2.8% and 5.3%) were lower in the 2PA-VMAT. All contralateral lung doses, especially cMLD (7.2 vs. 5.4 and 5.4 Gy), were higher in SA-VMAT technique than in others. Medulla spinalis Dmax (27.9 vs. 29.8 and 32.5 Gy) was lower in 2PA-VMAT and esophagus Dmean (13.8 vs. 15.5 and 14.1 Gy) and esophagus Dmax (51.2 vs. 54.5 and 54.8 Gy) were lower in IMRT plans.
Table 5: Dose-volume histogram in central tumors

Click here to view


In central tumors, total and ipsilateral lung and esophagus are preserved by IMRT, whereas 2PA-VMAT protects the contralateral lung and medulla spinalis.

Intensity-modulated radiotherapy and single-arc and 2 partial-arc volumetric modulated arc therapy techniques in patients with peripheral tumors: Monitor unit, CN, and homogeneity index

The comparative results of IMRT and VMAT techniques are summarized in [Table 6]. The MU values were higher in IMRT (657.95 ± 224.89) technique than SA-VMAT (466.10 ± 14.35) and PA-VMAT (454.70 ± 104.85) techniques. There was no statistically significant difference between the three techniques for HI. CN was significantly better in IMRT (0.86 ± 0.05) than SA-VMAT (0.83 ± 0.05) and 2PA-VMAT (0.78 ± 0.10) techniques.
Table 6: Monitor unit, conformation number, and homogeneity index in peripheral tumors

Click here to view


Intensity-modulated radiotherapy and single-arc and 2 partial-arc volumetric modulated arc therapy techniques in patients with central tumors: Monitor unit, CN, and homogeneity index

The comparative results of IMRT and VMAT techniques are summarized in [Table 7]. The MU values were higher in IMRT (815.16 ± 244.03) technique than SA-VMAT (501.25 ± 51.97) and PA-VMAT (489.41 ± 61.29) techniques. There was no statistically significant difference between the three techniques for HI and CN.
Table 7: Monitor unit, conformation number, and homogeneity index in central tumors

Click here to view



 > Discussion Top


Lung cancer is the leading cause of cancer-related deaths, and standard treatment of locally advanced lung cancer is concomitant cytotoxic CT with RT.[11] In the past, ENI was used in the treatment of locally advanced lung cancer, while at present, IFRT is performed. Accordingly, PTV has a more irregular shape and a complex structure. Providing the coverage of the complex target volume is also quite difficult with the old techniques.

In the past, locally advanced-stage NSCLC has been treated with three-dimensional conformal RT (3DCRT) and concurrent CT. However, currently, the use of IMRT and VMAT techniques has increased in lung cancer RT. Choosing the most appropriate RT technique in patients is important for both treatment efficacy and toxicity.

IMRT uses complex-modulated radiation beams shaping the radiation dose for target volumes with complex geometry and generates a sharper radiation gradient between the tumor and normal tissues compared to 3DCRT.[11] According to dosimetry studies, IMRT reduces the doses of the organs at risk such as lung, heart, and esophagus and provides better dose distribution than 3DCRT.[12] The clinical outcomes of IMRT with IGRT are quite good. When IMRT and VMAT are compared, the duration of MU and treatment is longer in IMRT.[2] Many studies have compared IMRT and VMAT technique in lung cancer, but only a few studies compared IMRT and VMAT in central and peripheral lung cancer.[6],[13] Studies have shown that VMAT was superior to IMRT, especially in solid tumors with complicated target volumes.[1],[3],[14],[15]

During the treatment of central tumor or mediastinal lymph node metastases, the esophagus is exposed to high-dose radiation. The esophagus requires lower doses due to its proximity to the medulla spinalis and the heart. Esophagus Dmax is associated with the development of esophagitis in many studies. Many studies have shown that esophagus Dmax >51 Gy during the treatment of lung cancer is associated with acute esophagitis.[16],[17],[18] The Quantitative Analysis of Normal Tissue Effects in the Clinic report and the Radiation Therapy Oncology Group 0617 study recommend that the esophagus Dmean should be <34 Gy.[19],[20] The risk of acute esophagitis is associated with esophagus Dmax and Dmean.

In a study conducted by Jiang et al., 12 patients with locally advanced-stage lung cancer were evaluated. Esophagus V55 and Dmean were compared between IMRT, SA-VMAT, and PA-VMAT techniques, and although V55 and Dmean were higher in PA-VMAT technique, there was no statistically significant difference.[6] The study by Wijsman et al. showed that when advanced-stage NSCLC patients were treated with IMRT or VMAT, only a limited increase of moderate-to-severe acute esophageal toxicity occurred after VMAT.[21] In our study, IMRT technique has preserved the esophagus better.

RP is one of the most common side effects due to high radiation dose during thorax irradiation and can lead to increased morbidity and mortality. Many studies have demonstrated the association of RP with DVH parameters.[22],[23],[24] Some of the dosimetric studies suggest that MLD is the most important factor in the development of RP.[23],[25],[26] Some studies have shown the relationship between tV20 and tV30, especially in Grade 3–5 RP development.[22],[23] The study by Schallenkamp et al. showed that tV10-13-15 was associated with RP development.[27] According to the study by Wang et al., tV5 is a parameter that increases the risk of ≥ Grade 2 RP.[24] Ipsilateral lung doses are also important for RP development. Oetzel et al. reported no risk for RP if iMLD was <15 Gy; however, RP increased by 13% if iMLD was 17.5–20 Gy, 21% if iMLD was 22.5–25 Gy, and 43% if iMLD was 27.5 Gy.[28] The study by Ramella et al. showed that iV20 >52%, iV30 >39%, and iMLD >22 Gy are risk factors for the development of RP.[29] Furthermore, iV5 >65% is considered a risk factor for RP.[30] A study performed by Song et al. showed that a contralateral cV5 ≥ 60% was a risk factor for ≥ Grade 3 RP.[31] Thus, total, ipsilateral, and contralateral lung doses are important for the development of RP. In the present study, total and ipsilateral lungs were better preserved by IMRT, whereas the contralateral lung was better preserved by the PA-VMAT technique. SA-VMAT technique was found to significantly increase the contralateral lung doses, especially in the central tumor group.


 > Conclusion Top


All three techniques have advantages in lung cancer RT. The use of hybrid techniques can provide these advantages in the same RT plan. Further studies are needed to support this idea.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
 > References Top

1.
Wolff D, Stieler F, Welzel G, Lorenz F, Abo-Madyan Y, Mai S, et al. Volumetric modulated arc therapy (VMAT) vs. serial tomotherapy, step-and-shoot IMRT and 3D-conformal RT for treatment of prostate cancer. Radiother Oncol 2009;93:226-33.  Back to cited text no. 1
    
2.
Otto K. Volumetric modulated arc therapy: IMRT in a single gantry arc. Med Phys 2008;35:310-7.  Back to cited text no. 2
    
3.
Cozzi L, Dinshaw KA, Shrivastava SK, Mahantshetty U, Engineer R, Deshpande DD, et al. A treatment planning study comparing volumetric arc modulation with rapidArc and fixed field IMRT for cervix uteri radiotherapy. Radiother Oncol 2008;89:180-91.  Back to cited text no. 3
    
4.
Dörr W, Herrmann T. Second primary tumors after radiotherapy for malignancies. Treatment-related parameters. Strahlenther Onkol 2002;178:357-62.  Back to cited text no. 4
    
5.
Hall EJ. Intensity-modulated radiation therapy, protons, and the risk of second cancers. Int J Radiat Oncol Biol Phys 2006;65:1-7.  Back to cited text no. 5
    
6.
Jiang X, Li T, Liu Y, Zhou L, Xu Y, Zhou X, et al. Planning analysis for locally advanced lung cancer: Dosimetric and efficiency comparisons between intensity-modulated radiotherapy (IMRT), single-arc/partial-arc volumetric modulated arc therapy (SA/PA-VMAT). Radiat Oncol 2011;6:140.  Back to cited text no. 6
    
7.
Kay FU, Kandathil A, Batra K, Saboo SS, Abbara S, Rajiah P. Revisions to the tumor, node, metastasis staging of lung cancer (8th edition): Rationale, radiologic findings and clinical implications. World J Radiol 2017;9:269-79.  Back to cited text no. 7
    
8.
ICRU Report 83: Prescribing, recording and reporting Photon- Beam Intensity-Modulated Radiation Therapy (IMRT). J ICRU 2010;10:1-106.  Back to cited text no. 8
    
9.
van't Riet A, Mak AC, Moerland MA, Elders LH, van der Zee W. A conformation number to quantify the degree of conformality in brachytherapy and external beam irradiation: Application to the prostate. Int J Radiat Oncol Biol Phys 1997;37:731-6.  Back to cited text no. 9
    
10.
Zhao N, Yang R, Wang J, Zhang X, Li J. An IMRT/VMAT technique for nonsmall cell lung cancer. Biomed Res Int 2015;2015:613060.  Back to cited text no. 10
    
11.
Chun SG, Hu C, Choy H, Komaki RU, Timmerman RD, Schild SE, et al. Impact of intensity-modulated radiation therapy technique for locally advanced non-small-cell lung cancer: A secondary analysis of the NRG oncology RTOG 0617 randomized clinical trial. J Clin Oncol 2017;35:56-62.  Back to cited text no. 11
    
12.
Liao ZX, Komaki RR, Thames HD Jr., Liu HH, Tucker SL, Mohan R, et al. Influence of technologic advances on outcomes in patients with unresectable, locally advanced non-small-cell lung cancer receiving concomitant chemoradiotherapy. Int J Radiat Oncol Biol Phys 2010;76:775-81.  Back to cited text no. 12
    
13.
Quan EM, Chang JY, Liao Z, Xia T, Yuan Z, Liu H, et al. Automated volumetric modulated arc therapy treatment planning for stage III lung cancer: How does it compare with intensity-modulated radio therapy? Int J Radiat Oncol Biol Phys 2012;84:e69-76.  Back to cited text no. 13
    
14.
Palma D, Vollans E, James K, Nakano S, Moiseenko V, Shaffer R, et al. Volumetric modulated arc therapy for delivery of prostate radiotherapy: Comparison with intensity-modulated radiotherapy and three-dimensional conformal radiotherapy. Int J Radiat Oncol Biol Phys 2008;72:996-1001.  Back to cited text no. 14
    
15.
Popescu CC, Olivotto IA, Beckham WA, Ansbacher W, Zavgorodni S, Shaffer R, et al. Volumetric modulated arc therapy improves dosimetry and reduces treatment time compared to conventional intensity-modulated radiotherapy for locoregional radiotherapy of left-sided breast cancer and internal mammary nodes. Int J Radiat Oncol Biol Phys 2010;76:287-95.  Back to cited text no. 15
    
16.
Etiz D, Bayman E, Akcay M, Sahin B, Bal C. Dosimetric and clinical predictors of acute esophagitis in lung cancer patients in turkey treated with radiotherapy. Asian Pac J Cancer Prev 2013;14:4223-8.  Back to cited text no. 16
    
17.
Singh AK, Lockett MA, Bradley JD. Predictors of radiation-induced esophageal toxicity in patients with non-small-cell lung cancer treated with three-dimensional conformal radiotherapy. Int J Radiat Oncol Biol Phys 2003;55:337-41.  Back to cited text no. 17
    
18.
Qiao WB, Zhao YH, Zhao YB, Wang RZ. Clinical and dosimetric factors of radiation-induced esophageal injury: Radiation-induced esophageal toxicity. World J Gastroenterol 2005;11:2626-9.  Back to cited text no. 18
    
19.
Werner-Wasik M, Yorke E, Deasy J, Nam J, Marks LB. Radiation dose-volume effects in the esophagus. Int J Radiat Oncol Biol Phys 2010;76:S86-93.  Back to cited text no. 19
    
20.
Bradley JD, Paulus R, Komaki R, Masters G, Blumenschein G, Schild S, et al. Standard-dose versus high-dose conformal radiotherapy with concurrent and consolidation carboplatin plus paclitaxel with or without cetuximab for patients with stage IIIA or IIIB non-small-cell lung cancer (RTOG 0617): A randomised, two-by-two factorial phase 3 study. Lancet Oncol 2015;16:187-99.  Back to cited text no. 20
    
21.
Wijsman R, Dankers F, Troost EG, Hoffmann AL, van der Heijden EH, de Geus-Oei LF, et al. Comparison of toxicity and outcome in advanced stage non-small cell lung cancer patients treated with intensity-modulated (chemo-) radiotherapy using IMRT or VMAT. Radiother Oncol 2017;122:295-9.  Back to cited text no. 21
    
22.
Hernando ML, Marks LB, Bentel GC, Zhou SM, Hollis D, Das SK, et al. Radiation-induced pulmonary toxicity: A dose-volume histogram analysis in 201 patients with lung cancer. Int J Radiat Oncol Biol Phys 2001;51:650-9.  Back to cited text no. 22
    
23.
Graham MV, Purdy JA, Emami B, Harms W, Bosch W, Lockett MA, et al. Clinical dose-volume histogram analysis for pneumonitis after 3D treatment for non-small cell lung cancer (NSCLC) Int J Radiat Oncol Biol Phys 1999;45:323-9.  Back to cited text no. 23
    
24.
Wang S, Liao Z, Wei X, Liu HH, Tucker SL, Hu CS, et al. Analysis of clinical and dosimetric factors associated with treatment-related pneumonitis (TRP) in patients with non-small-cell lung cancer (NSCLC) treated with concurrent chemotherapy and three-dimensional conformal radiotherapy (3D-CRT). Int J Radiat Oncol Biol Phys 2006;66:1399-407.  Back to cited text no. 24
    
25.
Ten Haken RK, Martel MK, Kessler ML, Hazuka MB, Lawrence TS, Robertson JM, et al. Use of veff and iso-NTCP in the implementation of dose escalation protocols. Int J Radiat Oncol Biol Phys 1993;27:689-95.  Back to cited text no. 25
    
26.
Seppenwoolde Y, Lebesque JV, de Jaeger K, Belderbos JS, Boersma LJ, Schilstra C, et al. Comparing different NTCP models that predict the incidence of radiation pneumonitis. Normal tissue complication probability. Int J Radiat Oncol Biol Phys 2003;55:724-35.  Back to cited text no. 26
    
27.
Schallenkamp JM, Miller RC, Brinkmann DH, Foote T, Garces YI. Incidence of radiation pneumonitis after thoracic irradiation: Dose-volume correlates. Int J Radiat Oncol Biol Phys 2007;67:410-6.  Back to cited text no. 27
    
28.
Oetzel D, Schraube P, Hensley F, Sroka-Pérez G, Menke M, Flentje M. Estimation of pneumonitis risk in three-dimensional treatment planning using dose-volume histogram analysis. Int J Radiat Oncol Biol Phys 1995;33:455-60.  Back to cited text no. 28
    
29.
Ramella S, Trodella L, Mineo TC, Pompeo E, Stimato G, Gaudino D, et al. Adding ipsilateral V20 and V30 to conventional dosimetric constraints predicts radiation pneumonitis in stage IIIA-B NSCLC treated with combined-modality therapy. Int J Radiat Oncol Biol Phys 2010;76:110-5.  Back to cited text no. 29
    
30.
Agrawal S, Kumar S, Lawrence A, Das MK, Kumar S. Ipsilateral lung dose volume parameters predict radiation pneumonitis in addition to classical dose volume parameters in locally advanced NSCLC treated with combined modality therapy. South Asian J Cancer 2014;3:13-5.  Back to cited text no. 30
[PUBMED]  [Full text]  
31.
Song CH, Pyo H, Moon SH, Kim TH, Kim DW, Cho KH, et al. Treatment-related pneumonitis and acute esophagitis in non-small-cell lung cancer patients treated with chemotherapy and helical tomotherapy. Int J Radiat Oncol Biol Phys 2010;78:651-8.  Back to cited text no. 31
    


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]



 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

  >Abstract>Introduction>Materials and Me...>Results>Discussion>Conclusion>Article Figures>Article Tables
  In this article
>References

 Article Access Statistics
    Viewed1002    
    Printed28    
    Emailed0    
    PDF Downloaded91    
    Comments [Add]    

Recommend this journal


[TAG2]
[TAG3]
[TAG4]