Equivalent dose in 2 Gy (EQD2) to pelvic lymph nodes using volume based prescription for three brachytherapy applicators — a dosimetric retrospective analysis
Abstract
BACKGROUND: Pelvic lymph node (PLN) metastasis has been included in the FIGO staging, so there is a need to determine the dose contribution from brachytherapy to ascertain the total delivered dose to the pelvic lymph nodes in cervical cancer. The aim of the study was to calculate the equivalent dose in 2 Gy (EQD2) of the pelvic lymph nodes (PLNs) based on volume prescription using three applicators.
Materials and methods: Forty-one patients who had undergone external beam radiotherapy followed by brachytherapy using tandem ovoids (TO), tandem ring (TR) and TO + free hand interstitial needles (TO + FH) applicators were taken for this study. 26 Gy in 4 fractions was prescribed to HRCTV. The external iliac node (ELN), internal iliac node (ILN) and obturator (OBT) were contoured and the median EQD2 of the lymph nodes was calculated.
RESULTS: The median bilateral EQD2 values of ELN were 1.55 Gy (TR), 1.75 Gy (TO), 1.9 Gy (TO + FH), of ILN these were 2.57 Gy (TR), 3.27 Gy (TO), 3.04 Gy (TO + FH), and of OBT these were 3.69 Gy (TR), 4.46 Gy (TO), 4.69 Gy (TO + FH), respectively. The total median EQD2 values of TR, TO and TO + FH were 52.71 Gy, 53.03 Gy, and 53.88–62.73 Gy, respectively.
CONCLUSION: Our study calculated the median EQD2 to the pelvic lymph nodes using three types of applicators in brachytherapy. This could serve as reference to decide on the EBRT boost dose while treating patients with enlarged pelvic lymph nodes.
Keywords: pelvic lymph nodesHDRbrachytherapyEQD2Co-60applicators
References
- Bhatla N, Berek JS, Cuello Fredes M, et al. Cancer of the cervix uteri. Int J Gynaecol Obstet. 2018; 143 Suppl 2(1): 22–36.
- Sakuragi N. Up-to-date management of lymph node metastasis and the role of tailored lymphadenectomy in cervical cancer. Int J Clin Oncol. 2007; 12(3): 165–175.
- Wujanto C, Choo BAi, Tan D, et al. Does external beam radiation boost to pelvic lymph nodes improve outcomes in patients with locally advanced cervical cancer? BMC Cancer. 2019; 19(1): 385.
- Oike T, Ohno T, Noda SE, et al. Can combined intracavitary/interstitial approach be an alternative to interstitial brachytherapy with the Martinez Universal Perineal Interstitial Template (MUPIT) in computed tomography-guided adaptive brachytherapy for bulky and/or irregularly shaped gynecological tumors? Radiat Oncol. 2014; 9: 222.
- Pötter R, Georg P, Dimopoulos J, et al. Clinical outcome of protocol based image (MRI) guided adaptive brachytherapy combined with 3D conformal radiotherapy with or without chemotherapy in patients with locally advanced cervical cancer. Radiotherapy and Oncology. 2011; 100(1): 116–123.
- Rivard MJ, Coursey BM, DeWerd LA, et al. Update of AAPM Task Group No. 43 Report: A revised AAPM protocol for brachytherapy dose calculations. Med Phys. 2004; 31(3): 633–674.
- Viswanathan AN, Dimopoulos J, Kirisits C, et al. Computed tomography versus magnetic resonance imaging-based contouring in cervical cancer brachytherapy: results of a prospective trial and preliminary guidelines for standardized contours. Int J Radiat Oncol Biol Phys. 2007; 68(2): 491–498.
- Chua GW, Foo YW, Tay GH, et al. Assessing dose contribution to pelvic lymph nodes in intracavitary brachytherapy for cervical cancer. J Contemp Brachytherapy. 2017; 9(4): 345–353.
- Hackett TE, Olt G, Sorosky JI, et al. Surgical predictors of para-aortic metastases in early-stage cervical carcinoma. Gynecol Oncol. 1995; 59(1): 15–19.
- International Commission on Radiation Units and Measurements Report. Prescribing, recording, and reporting brachytherapy for cancer of the cervix. ICRU report, Bedhesda 2013 2013: Bedhesda.
- Lee LJ, Sadow CA, Russell A, et al. Correlation of point B and lymph node dose in 3D-planned high-dose-rate cervical cancer brachytherapy. Int J Radiat Oncol Biol Phys. 2009; 75(3): 803–809.
- Lee Y, Rash DL, Stern RL, et al. Variation in High-Dose-Rate Brachytherapy Dose Contribution Among Pelvic Lymph Node Groups in Locally Advanced Cervical Cancer. Int J Radiat Oncol Biol Phys. 2014; 90(1): S478.
- Matsukawa H, Sasaki T, Hirayama R, et al. Assessment of the anatomical position of point B and the relationship between point B dose and the dose delivered to pelvic lymph nodes in CT-based high-dose-rate brachytherapy for uterine cervical cancer. J Contemp Brachytherapy. 2019; 11(2): 137–145.
- Ramlov A, Kroon PS, Jürgenliemk-Schulz IM, et al. Impact of radiation dose and standardized uptake value of (18)FDG PET on nodal control in locally advanced cervical cancer. Acta Oncol. 2015; 54(9): 1567–1573.
- Ariga T, Toita T, Kasuya G, et al. External beam boost irradiation for clinically positive pelvic nodes in patients with uterine cervical cancer. J Radiat Res. 2013; 54(4): 690–696.
- Grigsby PW, Singh AK, Siegel BA, et al. Lymph node control in cervical cancer. Int J Radiat Oncol Biol Phys. 2004; 59(3): 706–712.