Evaluation of Volumetric Doses of Organs at Risk in Carcinoma Cervix Patients with HDR Intracavitary Brachytherapy and Comparison of CTbased and Conventional Plans

Srivastava, Sachin Kumar; Painuly, N K; Mishra, Smita; Srivastava, Kirti; Singh, Navneet; Singh, Saumyendra Vikram; Bhatt, M L B

doi:10.31661/jbpe.v0i0.867

Cited by 4 publications

(3 citation statements)

References 21 publications

(30 reference statements)

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“…3D CT and MRI are standardly used both for GTV coverage and evaluation of the dose to organs at risk (OARs), in particular for brachytherapy. Many authors had found correlations between late radiation toxicities and total dose given both to the rectum and bladder, as well as other studies had tried to give a possible comparison between late radiation toxicities and volumetric doses (11)(12)(13)(14).…”

Section: Discussionmentioning

confidence: 99%

Volume Delineation in Cervical Cancer With T2 and Diffusion-weighted MRI: Agreement on Volumes Between Observers

Rosa

Pizzi

Augurio

et al. 2020

In Vivo

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Aim: To delineate cervical cancer gross tumor volume (GTV) on T2-magnetic resonance imaging (MRI) and apparent diffusion coefficient (ADC) maps, assessing volumes and inter-observer agreement between two observers. Patients and Methods: A radiologist and a radiation oncologist delineated GTV on T2 (T2 GTV) and ADC (ADC GTV) sequences. Dice similarity index (DICE) and Bland-Altman analysis were used to estimated concordance. Results: Mean T2 GTV and ADC GTV volumes were 43.84±71.47 cc and 37.28±68.92 cc according to the radiologist, and 43.4±70.44 cc and 36.65±69.21 cc according to the radiation oncologist. ADC led to statistically significantly smaller volumes compared to T2. The mean DICE index was 0.86 for T2 GTV and 0.84 for ADC GTV. The Bland-Altman plots globally showed concordance. Conclusion: GTV delineation was smaller in the ADC maps compared to T2-MRI, reaching an almost perfect agreement between observers. Thanks to this acceptable variability, adding functional imaging might provide more information for tumor delineation, improving reproducibility for image-guided adaptive radiotherapy. Nowadays, the mainstay of treatment for locally advanced cervical cancer (LACC) includes external beam radiotherapy (EBRT), concomitant chemotherapy and brachytherapy. T2weighted magnetic resonance imaging (MRI) is the imaging modality to be preferred for careful and accurate primary staging of the tumor (1, 2). Despite the extensive use of MRI, recent studies reported significant uncertainties in T2-weighted MRI delineation, describing a poor interobserver variability in brachytherapy target volume, represented by conformity indices of 0.58-0.60 for gross tumor volume (GTV) at brachytherapy, and 0.39-0.79 (mostly between 0.70-0.79) for high-risk clinical target volume (3, 4). Considering this aspect and the possible advantages of improved diagnostic techniques in a dose-intensification strategy, in particular in patients with higher risk of local relapse, its integration with diffusion-weighted MRI (DWI) might improve tumor volume definition in addition to patient outcome. In this way, a recent study demonstrated the accuracy of the apparent diffusion coefficient (ADC) map obtained at 2 weeks during radiotherapy in allowing an early prediction of treatment response (5). DWI-MRI is considered an encouraging functional imaging mode in the definition of a biological target volume, thanks to its capability for detecting highly metabolic regions. DWI-MRI evaluates the random motion of water molecules, mostly present in the extracellular space: compared to normal tissue, in cervical cancer, as in other neoplasms, tumor is densely cellular, showing restricted diffusion. This distribution is quantitatively well measured by ADC. In DWI, cancer has an increased signal intensity, which results in a reduction of the corresponding ADC map. It is well established that both DWI techniques as well as ADC measurement improves cervical cancer clinical assessment, regarding both tumor and nodal status, and histology (6). Few studies hav...

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Section: Discussionmentioning

confidence: 99%

Volume Delineation in Cervical Cancer With T2 and Diffusion-weighted MRI: Agreement on Volumes Between Observers

Rosa

Pizzi

Augurio

et al. 2020

In Vivo

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“…The ICRU recommends the use of rectal and bladder reference points for the dose assessment of normal organ tissues in HDR BT; however, with the continuous development of 3D BT technology, studies have confirmed that a DVH dose assessment based on CTV and OARs often differs from those based on ICRU reference points. DVH-based dose assessment results are more conformal and reliable, while TCP and NTCP calculations can be performed based on the results, which is conducive to individually designed radiotherapy plans and improved tumor control rates [24][25][26].…”

Section: Discussionmentioning

confidence: 99%

Radiobiological and dosimetric comparison of 60Co versus 192Ir high-dose-rate intracavitary-interstitial brachytherapy for cervical cancer

Wen

Wang

et al. 2022

Radiat Oncol

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Background High-dose-rate (HDR) intracavitary-interstitial brachytherapy (IC-ISBT) is an effective treatment for bulky, middle, and advanced cervical cancer. In this study, we compared the differences between 60Co and 192Ir HDR IC-ISBT plans in terms of radiobiological and dosimetric parameters, providing a reference for clinical workers in brachytherapy. Methods A total of 30 patients with cervical cancer receiving HDR IC-ISBT were included in this study, and IC-ISBT plans for each individual were designed with both 60Co and 192Ir at a prescribed dose of CTV D90 = 6 Gy while keeping the dose to OARs as low as possible. Physical dose and dose–volume parameters of CTV and OARs were extracted from TPS. The EQD2, EUBED, EUD, TCP, and NTCP were calculated using corresponding formulas. The differences between the 60Co and 192Ir IC-ISBT plans were compared using the paired t-test. Results In each patient's 60Co and 192Ir IC-ISBT plan, the average physical dose and EQD2 of 60Co were lower than those of 192Ir, and there were statistically significant differences in D2cc and D1cc for the OARs (p < 0.05); there were statistically significant differences in D0.1 cc for the bladder (p < 0.05) and no significant differences in D0.1 cc for the rectum or intestines (p > 0.05). The EUBED ratio (60Co/192Ir) at the CTV was mostly close to 1 when neither 60Co or 192Ir passed their half-lives or when both passed two half-lives, and the difference between them was not significant; at the OARs, the mean value of 60Co was lower than that of 192Ir. There was no statistical difference between 60Co and 192Ir in the EUD (93.93 versus 93.92 Gy, p > 0.05) and TCP (97.07% versus 97.08%, p > 0.05) of the tumors. The mean NTCP value of 60Co was lower than that of 192Ir. Conclusions Considering the CTV and OARs, the dosimetric parameters of 60Co and 192Ir are comparable. Compared with 192Ir, the use of 60Co for HDR IC-ISBT can ensure a similar tumor control probability while providing better protection to the OARs. In addition, 60Co has obvious economic advantages and can be promoted as a good alternative to 192Ir.

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“…In addition to these points, the dose to two other points, which are 1.5 cm superior and inferior to the ICRU bladder points should also be recorded. In a study by Srivastava et al [45], it was observed that the dose at a point 1.5 cm above the ICRU bladder point was higher than the ICRU bladder point dose. This means that the ICRU bladder point is not the true representation of the maximum point dose to the bladder (Figure 7).…”

Section: Two-dimensional Image-based Brachytherapymentioning

confidence: 93%

Radiotherapy in cervical cancer

Srivastava,

Singh Moirangthem,

Ghosh

et al. 2023

Cervical Cancer - Recent Advances and New Perspectives

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Radiotherapy plays a significant role in the management of cervix cancer. In recent decades, there have been several advancements in radiation therapy treatment techniques. Moving from conventional two-dimensional techniques to advanced techniques like 3D conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), and volumetric modulated radiation therapy (VMAT) has led to improvement in the treatment outcomes. The aim of radiation therapy is achieved by these advanced techniques, which deliver optimal tumoricidal doses to tumor volumes and minimal doses to the normal tissues around the tumor and can reduce toxicity more effectively than the conventional techniques. These external beam radiotherapy (EBRT) techniques along with brachytherapy play a significant role in the treatment of gynaecological cancer. Compared to point-based dose brachytherapy planning, better local control and lower toxicity have been associated with advanced image-based brachytherapy.

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Evaluation of Volumetric Doses of Organs at Risk in Carcinoma Cervix Patients with HDR Intracavitary Brachytherapy and Comparison of CTbased and Conventional Plans

Cited by 4 publications

References 21 publications

Volume Delineation in Cervical Cancer With T2 and Diffusion-weighted MRI: Agreement on Volumes Between Observers

Volume Delineation in Cervical Cancer With T2 and Diffusion-weighted MRI: Agreement on Volumes Between Observers

Radiobiological and dosimetric comparison of 60Co versus 192Ir high-dose-rate intracavitary-interstitial brachytherapy for cervical cancer

Radiotherapy in cervical cancer

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