The impact of dosimetric inadequacy on treatment outcome of nasopharyngeal carcinoma with IMRT

Ng, Wai Tong; Lee, Michael C. H.; Chang, Amy; Chan, Oscar S.H.; Chan, Lucy; Cheung, Florence; Hung, Wai Man; Chan, Connie; Lee, Anne W.M.

doi:10.1016/j.oraloncology.2014.01.017

Cited by 89 publications

(66 citation statements)

References 20 publications

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“…The contrast-enhanced planning CT images obtained were transferred to the Pinnacle3 treatment planning system (TPS, Philips Medical Systems, Pinnacle v8.0m, Milpitas, CA, USA) via LAN for target delineation. The pre- and post-IC MRI scans were employed for assisting contour through MRI-CT fusion; contrast-enhanced T1-weighted MRI scans were used.…”

Section: Methodsmentioning

confidence: 99%

“…New radiotherapy techniques, such as intensity-modulated radiotherapy (IMRT), have been widely used in the past decade for highly conformal dose distribution to the primary tumor and reduced dose delivery to organs at risk (OARs), thereby better protecting normal tissues 1,2. However, for patients with stage T3–4 NPC, a common problem encountered in planning IMRT is that the space between the primary tumor and neurological structures (eg, the spinal cord, brainstem, optic chiasm, and nerves) is extremely narrow 3,4. Thus, it is difficult to optimize the dose in the overlapping region.…”

Section: Introductionmentioning

confidence: 99%

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Induction chemotherapy followed by intensity-modulated radiotherapy with reduced gross tumor volume delineation for stage T3-4 nasopharyngeal carcinoma

Xue¹,

Hu²,

He³

2017

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PurposeA common problem in stage T3–4 nasopharyngeal carcinoma (NPC) is the narrow gap between the primary tumor and neurological structures, which makes dose optimization difficult. Considering that significant tumor shrinkage may occur during induction chemotherapy (IC), this study explored the efficacy of intensity-modulated radiotherapy (IMRT) using reduced gross tumor volume (GTV) in the treatment of T3–4 NPC.Patients and methodsBetween January 2009 and April 2014, 103 patients with non-metastatic stage T3–4 NPC were prospectively recruited. They were assigned to accept IC, followed by reduced-volume IMRT and adjuvant chemotherapy. GTV was based on the post-IC volume of intracavity tumors and lymph nodes, and the pre-IC volume of the remaining involved structures.ResultsFor all treated patients, the 3-year local failure-free survival (LFFS) was 91.9%. After IC, 91 (88.3%) patients achieved local objective response (OR), and their 3-year LFFS rates were significantly better than in patients who failed to achieve local OR (94.1% vs 75.0%, P=0.023). A multivariate analysis demonstrated the prognostic value of tumor response to IC for LFFS. Dosimetric analysis showed good homogeneity, and the dose constraints were stringent. Asymptomatic temporal lobe necrosis in the ipsilateral side of tumor occurred in one patient.ConclusionIMRT using a reduced GTV delineation delivered satisfactory doses to the target volumes and avoided overdosing of critical neurological structures. Results showed satisfactory survival outcomes with few treatment-related toxicities. Tumor response to IC could facilitate selection of patients with stage T3–4 NPC eligible for treatment with this method.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Induction chemotherapy followed by intensity-modulated radiotherapy with reduced gross tumor volume delineation for stage T3-4 nasopharyngeal carcinoma

Xue¹,

Hu²,

He³

2017

OTT

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“…However, it inevitably happens in some patients, especially those with advanced disease, and remains a very challenging problem to tackle. In modern series using IMRT, the reported local failure rate is 5% to 15% overall, and is much higher at 15% to 45% for T4 disease . Aggressive salvage treatment with a curative intent is advocated for locally recurrent NPC because many patients could still achieve long‐term survival .…”

Section: Introductionmentioning

confidence: 99%

Reirradiation with intensity‐modulated radiotherapy for locally recurrent T3 to T4 nasopharyngeal carcinoma

et al. 2016

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“…Ng et al 19 found that an underdosed GTVp of 3.4 cm 3 was a prognostic factor for local failure. Here, we demonstrated that the GTVnd was identified as an independent prognostic factor for OS, DFS, and DMFS.…”

Section: Discussionmentioning

confidence: 99%

“…Ng et al 19 reported that 48 cm 3 was identified as the critical cutoff GTV_P volume, and the large volume group (GTV_P ≥ 48 cm 3 ) had poorer 5-year DFS and OS rates than the small volume group. Chen et al 18 reported that the 5-year OS rate was significantly reduced for patients with a large tumor volume (> 50 mL).…”

Section: Discussionmentioning

confidence: 99%

The relations of dosimetric parameters with long‐term outcomes and late toxicities in advanced T‐stage nasopharyngeal carcinoma with IMRT

et al. 2019

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Background: Balancing the dose requirements between targets and normal tissue is a challenge in radiation of nasopharyngeal carcinoma (NPC). The purpose of this study is to evaluate the dosimetric parameters and clinical outcomes in NPC. Methods: We presented a retrospective review of patients with T3-4 NPC treated by intensity-modulated radiation therapy (IMRT). Patient characteristics, dosimetric parameters, and the follow-up data for survival and late toxicities were analyzed. Results: The 5-year overall survival, local relapse-free survival, and distant metastasis-free survival were 83.0%, 90.1%, and 82.4%, respectively. Multivariate analysis revealed that the volume of involved lymph node was an independent prognostic factor. The volume of primary tumor and the maximal dose were significant factors affecting temporal lobe injury. Conclusions: IMRT provided satisfactory local control for advanced T-stage NPC, with acceptable late toxicities. The dose constraint criteria of selected critical structures can be appropriately loosen. K E Y W O R D Sclinical outcomes, dosimetry, intensity-modulated radiation therapy, nasopharyngeal carcinoma, organ at risk

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The impact of dosimetric inadequacy on treatment outcome of nasopharyngeal carcinoma with IMRT

Cited by 89 publications

References 20 publications

Induction chemotherapy followed by intensity-modulated radiotherapy with reduced gross tumor volume delineation for stage T3-4 nasopharyngeal carcinoma

Induction chemotherapy followed by intensity-modulated radiotherapy with reduced gross tumor volume delineation for stage T3-4 nasopharyngeal carcinoma

Reirradiation with intensity‐modulated radiotherapy for locally recurrent T3 to T4 nasopharyngeal carcinoma

The relations of dosimetric parameters with long‐term outcomes and late toxicities in advanced T‐stage nasopharyngeal carcinoma with IMRT

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