Dosimetric study of RapidArc plans and conventional intensity modulated radiotherapy for prostate cancer involving seminal vesicles and pelvis lymph nodes

Birendra Rout, Mukka Chandra Shekar, Alok Kumar, Kanaparthy Muralidhar

Abstract


Purpose: The main purpose of this study is to (1) identify the continual diversity between conventional fixed field intensity modulation radiotherapy (IMRT) and RapidArc (RA) for high-risk prostate cancer; and (2) determine potential benefits and drawbacks of using for this type of treatment.

Methods: A cohort of 20 prostate cases including prostate, seminal vesicles and pelvic lymph nodes was selected for this study. The primary planning target volume (PTVP) and boost planning target volume (PTVB) were contoured. The total prescription dose was 75.6 Gy (45 Gy to PTVP and an additional 21.6 Gy to PTVB). Two plans were generated for each PTV: multiple 7-fields for IMRT and two arcs for RA.

Results: A Sigma index (IMRT: 2.75 ± 0.581; RA: 2.8 ± 0.738) for PTVP and (IMRT: 2.0 ± 0.484; RA: 2.1 ± 0.464) for PTVB indicated similar dose homogeneity inside the PTV. Conformity index (IMRT: 0.96 ± 0.047; RA: 0.95 ± 0.059) for PTVP and (IMRT: 0.97 ± 0.015; RA: 0.96 ± 0.014) for PTVB was comparable for both the techniques. IMRT offered lower mean dose to organ at risks (OARs) compared to RA plans. Normal tissue integral dose in IMRT plan resulted 0.87% lower than RA plans. All the plans displayed significant increase (2.50 times for PTVP and 1.72 for PTBB) in the average number of necessary monitor units (MUs) with IMRT beam. Treatment delivery time of RA was 2 ‒ 6 minutes shorter than IMRT treatment.

Conclusion: For PTV including pelvic lymph nodes, seminal vesicles and prostate, IMRT offered a greater degree of OARs sparing. For PTV including seminal vesicles and prostate, RA with two arcs provided comparable plan with IMRT. RA also improved the treatment efficiency due to smaller number of MUs required.


Keywords


IMRT, RapidArc, Sigma-Index, Conformity Index, Normal Tissue Integral Dose

Full Text:

PDF

References


Ferlay J, Soerjomataram I, Ervik M, et al, GLOBOCAN 2012 v1.0, Cancer Incidence and Mortality Worldwide: IARC Cancer Base No. 11, Lyon, France: International Agency for Research on Cancer. Available from http://globocan.iarc.fr. 2013.

Hall EJ. Intensity modulated radiation therapy, protons, and risk of second cancers. Int J Radiat Oncol Bio Phys. 2006; 65:1-7.

Nguyen PL, Gu X, Lipsitz SR, et al. Cost implications of the rapid adoption of newer technologies for treating prostate cancer. J Clin Oncol. 2011; 29:1517-24.

Rukstalis DB. Treatment options after failure of radiation therapy-a review. Rev Urol. 2002; 4 Suppl 2:S12-7.

Heidenreich A, Bolla M, Joniau S, et al. Guidelines on prostate cancer. European association of urology, 2010.

Otto K. Volumetric modulated arc therapy: IMRT in a single gantry arc. Med Phys. 2008; 35:310-7.

Ojala J. The accuracy of the Acuros XB algorithm in external beam radiotherapy – a comprehensive review. Int J Cancer Ther Oncol 2014; 2:020417.

Rana S, Rogers K, Lee T, et al. Dosimetric impact of Acuros XB dose calculation algorithm in prostate cancer treatment using RapidArc. J Cancer Res Ther. 2013; 9:430-5.

Rout BK, Muralidhar KR, Ali M, et al. Dosimetric study of RapidArc plans with flattened beam (FB) and flattening filter-free (FFF) beam for localized prostate cancer based on physical indices. Int J Cancer Ther Oncol. 2014; 2:02046.

Sun M, Ma L. Treatment exceptionally large prostate cancer patients with low-energy intensity-modulated photons. J Appl Clin Med Phys. 2006; 7:43-9.

Yoon M, Park SY, Shin D, et al. A new homogeneity index based on statistical analysis of the dose-volume histogram. J Appl Clin Med Phys. 2007; 8:9-17.

Marks LB, Yorke ED, Jackson A, et al. Use of normal tissue complication probability models in the clinic. Int J Radiat Oncol Biol Phys. 2010; 76:S10-9.

Michalski JM, Purdy JA, Winter K, et al. Preliminary report of toxicity following 3D radiation therapy for prostate cancer on 3DOG/RTOG 9406. Int J Radiat Oncol Bio Phys. 2000; 46:391-402.

Followill D, Geis P, Boyer A. Estimates of whole-body dose equivalent produced by beam intensity modulated conformal therapy. Int J RadiatOncol Biol Phys. 1997; 38:667-72.

Miften MM, Das SK, Su M, Marks LB. A dose-volume based tool for evaluating and ranking IMRT plans. J Appl clin Med Phys. 2004; 5:1-14.

Yoo S, Wu QJ, Lee WR, Yin FF. Radiotherapy treatment plans with RapidArc for prostate cancer involving seminal vesicles and lymph nodes. Int J Radiat Oncol Biol Phys. 2010; 76:935-42.

Kjaer-Kristoffersen F, Ohlhues L, Medin J, Korreman S. RapidArc volumetric modulation therapy planning for prostate cancer patients. Acta Oncol. 2009; 48:227-32.

Brenner DJ, Curtis RE, Hall EJ, Ron E. Second malignancies in prostate carcinoma patients after radiotherapy compared with surgery. Cancer. 2000;88:398-406.

Hall EJ, Wuu CS. Radiation-induced second cancers: The impact of 3D-CRT and IMRT. Int J Radiat Oncol Biol Phys. 2003; 56:83-8.

Palma D, Vollans E, James K, et al. Volumetric modulated arc therapy for delivery of prostate radiotherapy: Comparision with intensity modulated radiotherapy and three dimensional conformal radiotherapy. Int J Radiant Oncol Biol Phys. 2008;72:996-1001.

Isa M, Rehman J, Afzal M, Chow JC. Dosimetric dependence on the collimator angle in prostate volumetric modulated arc therapy. Int J Cancer Ther Oncol 2014; 2:020419.

Tesfamicael BY, Avery S, Gueye P, et al. Scintillating fiber based in-vivo dose monitoring system to the rectum in proton therapy of prostate cancer: A Geant4 Monte Carlo simulation. Int J Cancer Ther Oncol. 2014; 2:02024.

Rana S, Larson G, Vargas C, et al. Intensity modulated proton therapy versus uniform scanning proton therapy: Treatment planning study of the prostate cancer in patients with a unilateral metallic hip prosthesis. Jour Proton Ther. 2015; 1:113.

Vargas C, Fryer A, Mahajan C, et al. Dose-volume comparison of proton therapy and intensity-modulated radiotherapy for prostate cancer. Int J Radiat Oncol Biol phys. 2008; 70:744-51.

Rana S, Cheng C, Zheng Y, et al. Proton therapy vs. VMAT for prostate cancer: a treatment planning study. Int J Particle Ther. 2014;1:22–33.




DOI: http://dx.doi.org/10.14319/ijcto.41.8

Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.

------------------------------------------------------------

International Journal of Cancer Therapy and Oncology (ISSN 2330-4049)

© International Journal of Cancer Therapy and Oncology (IJCTO)

To make sure that you can receive messages from us, please add the 'ijcto.org' domain to your e-mail 'safe list'. If you do not receive e-mail in your 'inbox', check your 'bulk mail' or 'junk mail' folders.

------------------------------------------------------------

Number of visits since October, 2013
AmazingCounters.com