Long-term outcomes of replanning during intensity-modulated radiation therapy in patients with nasopharyngeal carcinoma: An updated and expanded retrospective analysis

Zhou, Xiate; Wang, Wei; Zhou, Chao; Zhu, Jian; Ding, Wei; Chen, Meng; Chen, Kuifei; Shi, Yangyang; Chen, Xiaofeng; Kong, Feng-Ming Spring; Yang, Haihua

doi:10.1016/j.radonc.2022.03.007

Cited by 15 publications

(16 citation statements)

References 37 publications

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Section: Discussionmentioning

confidence: 99%

“…Several studies have demonstrated the dosimetric advantages of ART in HNC for sparing parotids and restoring target coverage; plan adaptation may improve the treatment outcomes and the patient's quality of life. 24,25 Clinical evidence also indicates that not all patients need adaptation during radiotherapy. 2 In this context, DDA offers a patient-specific decision tool to trigger plan adaption if required; however, the complexity of dose mapping and the underlying uncertainties have questioned its reliability and limited its clinical use.…”

Section: Discussionmentioning

confidence: 99%

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Incorporating uncertainty bounds in daily deformable dose accumulation for adaptive radiation therapy of head‐and‐neck cancer

et al. 2022

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Background:The widespread use of deformable dose accumulation (DDA) in adaptive radiotherapy (ART) has been limited due to the lack of clinically compatible methods to consider its related uncertainties. Purpose: We estimate dose reconstruction uncertainties in daily DDA during CT-guided radiotherapy of head-and-neck cancer (HNC).We project confidence intervals of cumulative dose-volume parameters to the parotids and determine threshold values to guide clinical decision-making in ART. Methods: Doses from daily images (megavoltage CTs [MVCTs]) of 20 HNC patients treated with tomotherapy were reconstructed and accumulated in the planning CT (PCT) utilizing a commercial DDA algorithm (PreciseART, Accuray, Inc.). For each mapped fraction, we warped the planning contours to the MVCT. Dose-volume histograms (DVHs) calculated in the MVCT (with warped contour and native dose) and the PCT (with native contour and mapped dose) were compared; the observed inconsistencies were associated with dose reconstruction errors. We derived uncertainty bounds for the transferred dose to voxels within the structure of interest in the PCT. The confidence intervals of cumulative dose-volume parameters were mid-treatment projected and evaluated as predictors of the end of treatment cumulative metrics. The need for plan adaptation was tested by comparing the projected uncertainty bounds with the treatment constraint points. Results: Among all cases, the uncertainty in mean values of daily dose distributions mapped to the reference parotid's contours averaged between 2.8% and 3.8% of typical single fraction planning values and less than 1% for the planning target volume (PTV) D95%. These daily inconsistencies were higher in the ipsilateral compared to the contralateral parotid and increased toward the end of treatment. The magnitude of the uncertainty bounds for the cumulative treatment mean dose, D50%, and V20 Gy to the parotids, and PTV D95% were on average 3.5%, 6.6%, 4.6%, and 0.4% of the planned or prescribed values, with confidence intervals of 97.1%-107.0%, 98.2%-110.4%, 95.6%-111.1%, and 98.2%-100.2% respectively. The uncertainty intervals projected at midtreatment intersected with the end of treatment bounds in 82% of the parotid's metrics; half of them presented an overlapping percentage greater than 60%. In five patients, the cumulative mean doses were projected at mid-treatment to exceed the total treatment constraint point by at least 3%; this threshold was exceeded at the end of treatment in the five cases. Underdosing was projected in only one case; the cumulative PTV D95% at the end of treatment was below the clinical threshold. Conclusion: Uncertainty bounds were incorporated into the results of a commercial DDA tool. The cohort's statistics showed that the parotids' cumulative 2474

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Incorporating uncertainty bounds in daily deformable dose accumulation for adaptive radiation therapy of head‐and‐neck cancer

et al. 2022

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“…Totally 307 participants were identi ed, and 274 participants took part in the research. One hundred and seventy-nine patients who were treated between August 2011 and December 2015 were part of our previous study 12 . Patients with at least one metastatic disease at the time of rst diagnosis (n = 22), recurrent disease (n = 6), and failure to accomplish the full course of IMRT (n = 5) were eliminated from the study.…”

Section: Patientsmentioning

confidence: 99%

“…Ultimately, patients who declined a second simulation CT scan during the course of IMRT were given IMRT without adaptive replanning, while other patients had IMRT with replanning. The re-simulation CT scan and replanning were carried out at the 15th and/or the 25th fraction of IMRT as we previously reported 15 . The replanning GTVs was described as residual shrunken tumor and positive lymph nodes.…”

Section: Adaptive Replanningmentioning

confidence: 99%

Failure patterns of locoregional recurrence after reducing target volumes in patients with nasopharyngeal carcinoma receiving adaptive replanning during intensity-modulated radiotherapy: A single-center experience in China

Zhou

Zhu

Zhou

et al. 2023

Preprint

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Background Previous researches have demonstrated that adaptive replanning during intensity-modulated radiation therapy (IMRT) could enhance the prognosis of patients with nasopharyngeal carcinoma (NPC). However, the delineation of replanning target volumes remains unclear. This study aimed to evaluate the feasibility of reducing target volumes through adaptive replanning during IMRT by analyzing long-term survival outcomes and failure patterns of locoregional recurrence in NPC. Methods This study enrolled consecutive NPC patients who received IMRT at our hospital between August 2011 and April 2018. Patients with initially diagnosed, histologically verified, non-metastatic nasopharyngeal cancer were eligible for participation in this study. The location and extent of locoregional recurrences were transferred to pretreatment planning computed tomography for dosimetry analysis. Results Among 274 patients, 100 (36.5%) received IMRT without replanning and 174 (63.5%) received IMRT with replanning. Five-year rates of locoregional recurrence-free survival (LRFS) were 90.1% (95%CI, 84.8–95.4%) and 80.8% (95%CI, 72.0–89.6%) for patients with and without replanning, p = 0.045. There were 17 locoregional recurrences in 15 patients among patients with replanning, of which 1 (5.9%) was out-field and 16 (94.1%) were in-field. Among patients without replanning, 19 patients developed locoregional recurrences, of which 1 (5.3%) was out-field, 2 (10.5%) were marginal, and 16 (84.2%) were in-field. Conclusions In-field failure inside the high dose area was the most common locoregional recurrent pattern for non-metastatic NPC. Adapting the target volumes and modifying the radiation dose prescribed to the area of tumor reduction during IMRT were feasible and would not cause additional recurrence in the shrunken area.

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“…Compared with conventional treatment, the adaptive re-planning of definitive radiotherapy for NPC resulted in a higher quality of life and short-term loco-regional control (97.2% vs. 92.4%) in retrospective studies [ 63 , 64 ]. Target coverage and OAR dosimetry were also significantly improved [ 65 ]. Nevertheless, thus far, no prospective comparative trials on adaptive radiotherapy for NPC have been conducted.…”

Section: Future Directionsmentioning

confidence: 99%

Current Radiotherapy Considerations for Nasopharyngeal Carcinoma

Chow

Beitler³

et al. 2022

Cancers

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Radiotherapy is the primary treatment modality for nasopharyngeal carcinoma (NPC). Successful curative treatment requires optimal radiotherapy planning and precise beam delivery that maximizes locoregional control while minimizing treatment-related side effects. In this article, we highlight considerations in target delineation, radiation dose, and the adoption of technological advances with the aim of optimizing the benefits of radiotherapy in NPC patients.

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Long-term outcomes of replanning during intensity-modulated radiation therapy in patients with nasopharyngeal carcinoma: An updated and expanded retrospective analysis

Cited by 15 publications

References 37 publications

Incorporating uncertainty bounds in daily deformable dose accumulation for adaptive radiation therapy of head‐and‐neck cancer

Incorporating uncertainty bounds in daily deformable dose accumulation for adaptive radiation therapy of head‐and‐neck cancer

Failure patterns of locoregional recurrence after reducing target volumes in patients with nasopharyngeal carcinoma receiving adaptive replanning during intensity-modulated radiotherapy: A single-center experience in China

Current Radiotherapy Considerations for Nasopharyngeal Carcinoma

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