Automated Weekly Replanning for Intensity-Modulated Radiotherapy of Cervix Cancer

Stewart, James; Lim, Karen; Kelly, Valerie J.; Xie, Jiawen; Brock, Kristy K.; Moseley, Joanne; Cho, Young Bin; Fyles, Anthony; Lundin, Anna; Rehbinder, H.; Löf, Johan; Jaffray, David A.; Milosevic, Michael

doi:10.1016/j.ijrobp.2009.07.1699

Cited by 64 publications

(62 citation statements)

References 25 publications

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“…Planned dose parameters for the volumes receiving 15 Gy (V 15Gy ), 30 Gy (V 30Gy ) and 45 Gy (V 45Gy ) were extracted [4,19]. Because we aim to treat with a full bladder to minimize bowel irradiation, only planned dose parameters of library plans representing the full bladder planning CT anatomy were evaluated.…”

Section: Planned Dose Distributionsmentioning

confidence: 99%

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Dosimetric advantages of proton therapy compared with photon therapy using an adaptive strategy in cervical cancer

et al. 2016

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Background Image-guided adaptive proton therapy (IGAPT) can potentially be applied to take into account interfraction motion while limiting organ at risk (OAR) dose in cervical cancer radiation therapy (RT). In this study, the potential dosimetric advantages of IGAPT compared with photonbased image-guided adaptive RT (IGART) were investigated. Material and methods For 13 cervical cancer patients, full and empty bladder planning computed tomography (CT) images and weekly CTs were acquired. Based on both primary clinical target volumes (pCTVs) [i.e. gross tumor volume (GTV), cervix, corpus-uterus and upper part of the vagina] on planning CTs, the pretreatment observed full range primary internal target volume (pITV) was interpolated to derive pITV subranges. Given corresponding ITVs (i.e. pITVs including lymph nodes), patient-specific photon and proton plan libraries were generated. Using all weekly CTs, IGART and IGAPT treatments were simulated by selecting library plans and recalculating the dose. For each recalculated IGART and IGAPT fraction, CTV (i.e. pCTV including lymph nodes) coverage was assessed and differences in fractionated substitutes of dose-volume histogram (DVH) parameters (V 15Gy , V 30Gy , V 45Gy , D mean , D 2cc ) for bladder, bowel and rectum were tested for significance (Wilcoxon signed-rank test). Also, differences in toxicity-related DVH parameters (rectum V 30Gy , bowel V 45Gy ) were approximated based on accumulated dose distributions. Results In 92% (96%) of all recalculated IGAPT (IGART) fractions adequate CTV coverage (V 95% 498%) was obtained. All dose parameters for bladder, bowel and rectum, except the fractionated substitute for rectum V 45Gy , were improved using IGAPT. Also, IGAPT reduced the mean dose to bowel, bladder and rectum significantly (p50.01). In addition, an average decrease of rectum V 30Gy and bowel V 45Gy indicated reductions in toxicity probabilities when using IGAPT. Conclusion This study demonstrates the feasibility of IGAPT in cervical cancer using a plan-library based plan-of-the-day approach. Compared to photon-based IGART, IGAPT maintains target coverage while significant dose reductions for the bladder, bowel and rectum can be achieved.

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Section: Planned Dose Distributionsmentioning

confidence: 99%

“…This is known as adaptive RT (ART) and several ART strategies have been investigated [4,5]. Similar to our current clinical practice, a practical approach frequently applied for pelvic EBRT is the plan-library based plan-of-the-day strategy [6,7].…”

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confidence: 99%

Dosimetric advantages of proton therapy compared with photon therapy using an adaptive strategy in cervical cancer

et al. 2016

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“…Several adaptive strategies, both offline and online approaches, have been investigated [4,5]. The most widely reported approach for pelvic EBRT is the plan-library based plan-of-the-day strategy [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Dosimetric advantages of a clinical daily adaptive plan selection strategy compared with a non-adaptive strategy in cervical cancer radiation therapy

et al. 2017

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Background: Radiation therapy (RT) using a daily plan selection adaptive strategy can be applied to account for interfraction organ motion while limiting organ at risk dose. The aim of this study was to quantify the dosimetric consequences of daily plan selection compared with non-adaptive RT in cervical cancer. Material and methods: Ten consecutive patients who received pelvic irradiation, planning CTs (full and empty bladder), weekly post-fraction CTs and pre-fraction CBCTs were included. Non-adaptive plans were generated based on the PTV defined using the full bladder planning CT. For the adaptive strategy, multiple PTVs were created based on both planning CTs by ITVs of the primary CTVs (i.e., GTV, cervix, corpus-uterus and upper part of the vagina) and corresponding library plans were generated. Daily CBCTs were rigidly aligned to the full bladder planning CT for plan selection. For daily plan recalculation, selected CTs based on initial similarity were deformably registered to CBCTs. Differences in daily target coverage (D 98% > 95%) and in V 0.5Gy , V 1.5Gy , V 2Gy , D 50% and D 2% for rectum, bladder and bowel were assessed. Results: Non-adaptive RT showed inadequate primary CTV coverage in 17% of the daily fractions. Plan selection compensated for anatomical changes and improved primary CTV coverage significantly (p < 0.01) to 98%. Compared with non-adaptive RT, plan selection decreased the fraction dose to rectum and bowel indicated by significant (p < 0.01) improvements for daily V 0.5Gy , V 1.5Gy , V 2Gy , D 50% and D 2% . However, daily plan selection significantly increased the bladder V 1.5Gy , V 2Gy , D 50% and D 2% . Conclusions: In cervical cancer RT, a non-adaptive strategy led to inadequate target coverage for individual patients. Daily plan selection corrected for day-to-day anatomical variations and resulted in adequate target coverage in all fractions. The dose to bowel and rectum was decreased significantly when applying adaptive RT.

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“…However, the majority of the studies in this review adapted the treatment for all patients with only about 17% of the clinically applied ART and 18% of the in silico studies followed a workflow allowing for selective use of ART. Examples of patient selection in the reviewed workflows were, applied alone or in combination: exerting a threshold criteria on the detected motion for initiation of modifications [20,45,46,[61][62][63][64]69,72] or shrinking the PTV margins to less than the common 90% of the population and correct for dose degradation of outliers during/at the end of treatment [63,65,66,94]. As an alternative, differentiating the size of the plan library based on a criterion for large and small cervix-uterus [41] or discriminating the adaptations based on greater and smaller response to treatment as in the gynecological GEC-ESTRO recommendations has been applied clinically [42].…”

Section: Discussionmentioning

confidence: 99%

Adaptive radiotherapy strategies for pelvic tumors – a systematic review of clinical implementations

et al. 2016

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Automated Weekly Replanning for Intensity-Modulated Radiotherapy of Cervix Cancer

Cited by 64 publications

References 25 publications

Dosimetric advantages of proton therapy compared with photon therapy using an adaptive strategy in cervical cancer

Dosimetric advantages of proton therapy compared with photon therapy using an adaptive strategy in cervical cancer

Dosimetric advantages of a clinical daily adaptive plan selection strategy compared with a non-adaptive strategy in cervical cancer radiation therapy

Adaptive radiotherapy strategies for pelvic tumors – a systematic review of clinical implementations

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