Factors Affecting “Organs at Risk” Doses in 3 Dimensional Brachytherapy (3D BRT) of Cervical and Endometrium Cancers

Abstract

In brachytherapy, both the tumor and organ at risk may have intrafractional and interfractional anatomical differences. In this study, we aimed to investigate the factors affecting Organs at Risk (OAR) doses in adaptive 3D BRT applications. A total of 55 patients that underwent intracavitary brachytherapy with the diagnosis of a gynecological tumor between September 2012 and December 2013 were evaluated retrospectively. The effect of the surgery, applicator type, bladder, rectum and sigmoid on D2cc, D1cc, D0.1cc values were investigated. The median age was 55 years. While there was no statistically significant difference between 1st and 2nd fractions measurements, the sigmoid D1cc values between the 1st and 3rd fractions were found to be statistically significant (p = 0.004). When the effect of the interfractional change of bladder filling on OAR doses in the first three fractions was examined, it was not statistically significant however, its effect on bladder, sigmoid and rectum D2cc, D1cc, D0.1cc values were observed in some fractions. The bladder point dose was found to be statistically significant in operated patients (p= 0.005). When the comparison was made according to the application type, the bladder dose was found to be statistically significant in roller applications than the other two applicator treatments (p= 0.001). 3D BRT provides maximum protection of healthy tissues while giving a high dose to the target as a result of adaptive planning by performing computed tomography in each fraction. The sigmoid is the OAR that makes the most distinctive interfraction. To obtain higher treatment accuracy in each fraction, routine preparation and tomographic imaging followed by adaptive planning should be done.

Keywords

• Brachytherapy
• volume of bladder
• cervix cancer
• endometrial cancer

Kaynakça

1. 1. World Health Organization. Global Health Observatory. Geneva: World Health Organization; 2018. who.int/gho/database/en/. Accessed June 21, 2018.
2. 2. Kizilkaya HO, Kutluhan Dogan A, Dag Z et all, A Comparison of Magnetic Resonance and Computed Tomography Imaging Based Target-Volume Definition and Interfraction Variations of Treatment Planning Parameters (D90 HR-CTV, D2cc for OARs) During Image Guided Adaptive Brachytherapy for Cervical Cancer. UHOD 2019; 29(4): 227-237.
3. 3. Marks LB1, Carroll PR, Dugan TC et all. The response of the urinary bladder, urethra, and ureter to radiation and chemotherapy. Int J Radiat Oncol Biol Phys 1995;31:1257-80.
4. 4. Pötter R, Kirisits C, Fidarova E, et al. Present status and future of high-precision image guided adaptive brachytherapy for cervix carcinoma. Acta Oncologica 2008;47:1325–36.
5. 5. Tanderup K, Georg D, Pötter R, et al. Adaptive management of cervical cancer radiotherapy. Semin Radiat Oncol 2010:121–9.
6. 6. Viswanathan AN, Thomadsen B American Brachytherapy Society Cervical Cancer Recommendations Committee, American Brachytherapy Society. American Brachytherapy Society consensus guidelines for locally advanced carcinoma of the cervix. Part I: General principles. Brachytherapy. 2012;11:33–46.
7. 7. Dankulchai P, Petsuksiri J, Chansilpa Y, et al. Image-guided high-dose-rate brachytherapy in inoperable endometrial cancer. Br J Radiol. 2014;87:20140018.
8. 8. Van den Bos W, Beriwal S, Velema L, et al. Image guided adaptive brachytherapy for cervical cancer: Dose contribution to involved pelvic nodes in two cancer centers. J Contemp Brachytherapy. 2014;6:21–7.

9. 9. Rangarajan R. Interfraction Variations in Organ Filling and Their Impact on Dosimetry in CT Image Based HDR Intracavitary Brachytherapy. J Med Phys. 2018;43(1):23‐27
10. 10. Patra NB1, Manir KS, Basu S, et al., Effect of bladder distension on dosimetry of organs at risk in computer tomography based planning of high-dose-rate intracavitary brachytherapy for cervical cancer. J Contemp Brachytherapy 2013; 5, 1: 3–9
11. 11. Kim R. Y, M.D, Shen S, Lin HY, et al. Effects of bladder distension on organs at risk in 3D image-based planning of intracavitary brachytherapy for cervical cancer. Int J Radiat Oncol Biol Phys. 2010;76:485–9
12. 12. Adli M, Garipagaoglu M, Kocak Z. Effect of bladder distention on bladder base dose in gynaecological intracavitary high dose rate brachytherapy. Br J Radiol. 2009;82:243–8.
13. 13. Jamema S.V, Mahantshetty U, Tanderup K, et all. Inter-application variation of dose and spatial location of D2cm3 volumes of OARs during MR image based cervix brachytherapy 2013; Radiotherapy and Oncology 107: 58–62
14. 14. The GEC-ESTOAR Handbook of Brachytherapy. http://www.estro-education.org/ publications/ Documents/ GEC-ESTOARHandbookof Brachytherapy.html
15. 15. Viswanathan AN, Erickson BA. Three-dimensional imaging in gynecologic brachytherapy: a survey of the American Brachytherapy Society. Int J Radiat Oncol Biol Phys. 2010;76:104–9.
16. 16. Davidson MT, Yuen J, D'Souza DP, et al. Image-guided cervix high-dose-rate brachytherapy treatment planning: Does custom computed tomography planning for each insertion provide better conformal avoidance of organs at risk? Brachytherapy. 2008;7:37–42.
17. 17. Kirisits C, Lang S, Dimopoulos J, et al. Uncertainties when using only one MRI-based treatment plan for subsequent high-dose-rate tandem and ring applications in brachytherapy of cervix cancer. Radiother Oncol. 2006;81:269–75.
18. 18. Cengiz M, Gurdalli S, Selek U, et al. Effect of bladder distensionn on dose distribution of intracavitary brachytherapy for cervical cancer: Three-dimensional computed tomography plan evaluation. Int J Radiat Oncol Biol Phys 2008;70:464–468.
19. 19. Sun LM, Huang HY, Huand EY, et al. A prospective study to assess the bladder distention effects on dosimetry in intracavitary brachytherapy of cervical cancer via computer tomography- assisted techniques. Radiother Oncol 2005;77:77–82.
20. 20. Demirci F, Ozden S, Alpay Z, et al. The effects of abdominal hysterectomy on bladder neck and urinary incontinence. Aust N Z J Obstet Gynaecol 39:239-242, 1999.