Abstract
Background and PurposeMost locoregional recurrences after definitive radiotherapy for head and neck squamous cell carcinoma (HNSCC) develop “in-field.” Dose escalation while sparing organs at risk can be a good solution for improving local control without increasing adverse effects. This study investigated the safety and effectiveness of volumetric modulated arc therapy (VMAT) using intentionally internal high-dose policy (IIHDP) to treat neck lymph node metastases (NLNM) ≥ 2 cm in HNSCC patients.Materials and MethodsWe analyzed 71 NLNM from 51 HNSCC patients who had received definitive radiotherapy to treat NLNM ≥ 2 cm using the VMAT technique in our institution between February 2017 and August 2019. Thirty-seven NLNM from 25 patients were treated using IIHDP VMAT (group A), and 34 NLNM from 27 patients were treated with homogeneous-dose distribution policy (HDDP) VMAT (group B). One patient with three NLNM had one lymph node assigned to group A and the other two to group B. Adverse events and local recurrence-free survival (LRFS) was compared between the two groups.ResultsIn the median follow-up period of 527 days, there were no significant differences between the groups in terms of dermatitis or mucositis ≥ grade 2/3, but LRFS was significantly longer in group A (p = 0.007). In the Cox regression analysis after adjustment for the propensity score, group A also showed an apparently superior LFRS.ConclusionOur initial experience of IIHDP VMAT suggested that IIHDP VMAT to treat HNSCC neck lymph node metastases measuring ≥ 2 cm was feasible and possibly led to better local control than HDDP VMAT.
Highlights
Head and neck cancer is common worldwide, with more than 800,000 new cases and 400,000 deaths annually [1]
Lymph node metastases were excluded if Abbreviations: CT, computed tomography; CTCAE the Common Terminology Criteria for Adverse Events; CTV, clinical target volume; EBER, Epstein-Barr virus-encoded small ribonucleic acid; EBV, Epstein-Barr virus; FDG, fluorodeoxyglucose; GTV, gross tumor volume; HDDP, homogeneous-dose distribution policy; HNSCC, head and neck squamous cell carcinoma; HPV, human papilloma virus; IIHD, intentional internal high dose; IIHDP, intentionally internal high dose policy; Intensitymodulated radiotherapy (IMRT), intensity-modulated Radiotherapy; ISH, in situ hybridization; Local recurrence-free survival (LRFS), local recurrence free survival; MRI, magnetic resonance imaging; OAR, organ at risk; PET, positron emission tomography; PRV, planning risk volume; PTV, planning target volume; RNA, ribonucleic acid; SIB, simultaneous integrated boost; volumetric modulated arc therapy (VMAT), volumetric modulated-arc therapy
We evaluated whether the observed adverse grade 3 effects were associated with IIHDP VMAT, in accordance with NCI guidelines for investigators
Summary
Head and neck cancer is common worldwide, with more than 800,000 new cases and 400,000 deaths annually [1]. A previous study reported a patient with bulky uterine cervical cancer who showed complete response using brachytherapy with increasing radiation dose inside the tumor, while sparing organs at risk (OARs) [8]. This technique was named “intentional internal high dose policy (IIHDP)” brachytherapy and could be a new strategy for enhancing local tumor control without increasing treatment-related adverse effects. This study investigated the safety and effectiveness of volumetric modulated arc therapy (VMAT) using intentionally internal high-dose policy (IIHDP) to treat neck lymph node metastases (NLNM) ≥ 2 cm in HNSCC patients
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