Estimating second malignancy risk in intensity-modulated radiotherapy and volumetric-modulated arc therapy using a mechanistic radiobiological model in radiotherapy for carcinoma of left breast

Sakthivel, Vasanthan; Mani, Ganesh Kadirampatti; Mani, S.; Boopathy, Raghavendiran; Selvaraj, J.

doi:10.4103/jmp.jmp_89_17

Cited by 18 publications

(8 citation statements)

References 25 publications

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“…Our results compare very favorably with data from the literature. Fogliata et al, as well as Sakthivel et al showed a lower risk for second malignancy following t-IMRT as compared to t-VMAT [31, 39]. In our study, EAR was calculated exclusively using the full model described by Schneider et al, which best takes into account tissue and dose-dependent cell biological properties such as cell destruction and cell regeneration.…”

Section: Discussionmentioning

confidence: 98%

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Left breast irradiation with tangential intensity modulated radiotherapy (t-IMRT) versus tangential volumetric modulated arc therapy (t-VMAT): trade-offs between secondary cancer induction risk and optimal target coverage

et al. 2019

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Background Adjuvant radiotherapy is the standard treatment after breast-conserving surgery. According to meta-analyses, adjuvant 3d-conventional irradiation reduces the risk of local recurrence and thereby improves long-term survival by 5–10%. However, there is an unintended exposure of organs such as the heart, lungs and contralateral breast. Irradiation of the left breast has been related to long-term effects like increased rates of coronary events as well as second cancer induction. Modern radiotherapy techniques such as tangential intensity modulated radiotherapy (t-IMRT) and tangential volumetric modulated arc therapy (t-VMAT) and particularly deep inspiration breath hold (DIBH) technique have been developed in order to improve coverage of target volume and to reduce dose to normal tissue. The aim of this study was to compare t-IMRT-plans with t-VMAT-plans in DIBH position for left-sided breast irradiation in terms of normal tissue exposure, i.e. of lungs, heart, left anterior descending coronary artery (LADCA), as well as homogeneity (HI) and conformity index (CI) and excess absolute risk (EAR) for second cancer induction for organs at risk (OAR) after irradiation. Methods Twenty patients, diagnosed with left-sided breast cancer and treated with breast-preserving surgery, were included in this planning study. For each patient DIBH-t-IMRT plan using 5 to 7 beams and t-VMAT plan using four rotations were generated to achieve 95% dose coverage to 95% of the volume. Data were evaluated on the basis of dose-volume histograms: Cardiac dose and LADCA (mean and maximum dose, D25% and D45%), dose to ipsilateral and contralateral lung (mean, D20%, D30%), dose to contralateral breast (mean dose), total monitor units, V5% of total body and normal tissue integral dose (NTID). In addition, homogeneity index and conformity index, as well as the excess absolute risk (EAR) to estimate the risk of second malignancy were calculated. Results T-IMRT showed a significant reduction in mean cardiac dose of 26% ( p = 0.002) compared to t-VMAT, as well as a significant reduction in the mean dose to LADCA of 20% ( p = 0.03). Following t-IMRT, mean dose to the left lung was increased by 5% ( p = 0.006), whereas no significant difference was found in the mean dose to the right lung and contralateral breast between the two procedures. Monitor units were 31% ( p = 0.000004) lower for t-IMRT than for t-VMAT. T-IMRT technique significantly reduced normal tissue integral dose (NTID) by 19% ( p = 0.000005) and the V5% of total body by 24% ( p = 0.0007). In contrast, t-VMAT improved CI and HI by 2% ( p = 0.001) and 0.4% ( p = 0.00001), respectively. EAR with t-IMRT was significantly lower, especially for contralateral lung and contralateral breast (2–5/10...

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Section: Discussionmentioning

confidence: 98%

“…Sakthivel et al evaluated the relationship between number of MUs and EAR. According to their results, however, no strong relationship between the two parameters was seen [39].…”

Section: Discussionmentioning

confidence: 99%

Left breast irradiation with tangential intensity modulated radiotherapy (t-IMRT) versus tangential volumetric modulated arc therapy (t-VMAT): trade-offs between secondary cancer induction risk and optimal target coverage

et al. 2019

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“…[ 31 32 ] Many studies have suggested that radiobiological modeling that can instantly represent local tumor control and normal tissue complications is a key factor in choosing the optimal radiotherapy technique. [ 33 34 35 ]…”

Section: Discussionmentioning

confidence: 99%

Pediatric craniospinal irradiation – The implementation and use of normal tissue complication probability in comparing photon versus proton planning

Shobana¹,

Balasubramanian²

2021

J Med Phys

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Purpose: The preferred radiotherapy treatment for medulloblastoma is craniospinal irradiation (CSI). With the aim of developing the potential to reduce normal tissue dose and associated post-treatment complications with photon and proton radiotherapy techniques for CSI. This report aims to carefully compare and rank treatment planning and dosimetric outcomes for pediatric medulloblastoma patients using normal tissue complication probability (NTCP) formalism between photon (three-dimensional conformal radiotherapy, intensity-modulated radiotherapy [IMRT], volumetric-modulated arc therapy [VMAT], and HT) and proton CSI. Methods and Materials: The treatment data of eight pediatric patients who typically received CSI treatment were used in this study. The patients were 7 years of age on average, with ages ranging from 3 to 11 years. A prescription dose of 3600 cGy was delivered in 20 fractions by the established planning methods. The Niemierko's and Lyman–Kutcher–Burman models were followed to carefully estimate NTCP and compare different treatment plans. Results: The NTCP of VMAT plans in upper and middle thoracic volumes was relatively high compared to helical tomotherapy (HT) and pencil beam scanning (PBS) (all P < 0.05). PBS rather than IMRT and VMAT in the middle thoracic region ( P < 0.06) could significantly reduce the NTCP of the heart. PBS significantly reduced NTCP of the lungs and liver (all P < 0.05). Conclusion: The NTCP and tumor control probability (TCP) model-based plan ranking along with dosimetric indices will help the clinical practitioner or medical physicists to choose the best treatment plan for each patient based on their anatomical or clinical challenges.

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“…Many literatures have reported that leakage radiation would contribute to the integral dose to peripheral normal tissue. This may lead to increased risk of secondary malignancy (Sakthivel et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

Is High Definition MLC Dosimetrically Superior to Standard Definition MLC for SIB-SBRT for Carcinoma Prostate

Bijina

Ganesh

Pichandi

2019

Asian Pac J Cancer Prev

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Objective:The study was conducted to quantitatively evaluate the dosimetric effects of high definition (2.5 mm) and standard definition (5.0 mm) MLC on the quality of SBRT plans using SIB-IMRT and SIB-VMAT technique for carcinoma prostate and also to evaluate the dosimetric advantage of one technique over the other. Materials and Methods: Seventeen annonymized planning CT data sets were used to generate plans for both VMAT and IMRT techniques using 2.5 mm and 5.0 mm MLC.The prescription to the nodule was 45Gy in 5 fractions and to the prostate was 35Gy in 5 fractions.CI, GI, D 2% , D 98% , D 50% and V 95% for target; D 2% , Dmean, V 80% , V 20% for OAR's; V 5% of the irradiated volume, and delivered MU's were analyzed.An independent t-test was used to compare the plans. Patient specific QA for all plans were also performed and analyzed. Results: Minor difference in dosimetric indices was observed between 2.5mm and 5mm MLC VMAT plans, except D 2% (PTV35) and D 98% (GTV45) were better in 2.5mm MLC plans (p<0.05).D 2% and D 50% to GTV45 with p<0.009 and <0.03 respectively, and D 2% of bladder (p<0.03) were significantly lesser for VMAT plans compared to IMRT plans. GI was significantly better for 2.5mm MLC plans in both techniques (p<0.05). 2.5mm MLC plans on an average had 9.9% and 7% more MU for VMAT and IMRT plans respectively. Conclusion: All the plans provided adequate dose coverage to target. Highly gradient plans with better conformity were achieved with 2.5mm MLC and VMAT combination with an increase in MU delivered, compared to 5mm MLC plans.

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Estimating second malignancy risk in intensity-modulated radiotherapy and volumetric-modulated arc therapy using a mechanistic radiobiological model in radiotherapy for carcinoma of left breast

Cited by 18 publications

References 25 publications

Left breast irradiation with tangential intensity modulated radiotherapy (t-IMRT) versus tangential volumetric modulated arc therapy (t-VMAT): trade-offs between secondary cancer induction risk and optimal target coverage

Left breast irradiation with tangential intensity modulated radiotherapy (t-IMRT) versus tangential volumetric modulated arc therapy (t-VMAT): trade-offs between secondary cancer induction risk and optimal target coverage

Pediatric craniospinal irradiation – The implementation and use of normal tissue complication probability in comparing photon versus proton planning

Is High Definition MLC Dosimetrically Superior to Standard Definition MLC for SIB-SBRT for Carcinoma Prostate

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