Early clinical outcomes of helical tomotherapy/intensity‐modulated proton therapy combination in nasopharynx cancer

Abstract

This study aimed to evaluate the feasibility of combining helical tomotherapy (HT) and intensity‐modulated proton therapy (IMPT) in treating patients with nasopharynx cancer (NPC). From January 2016 to March 2018, 98 patients received definitive radiation therapy (RT) with concurrent chemotherapy (CCRT). Using simultaneous integrated boost and adaptive re‐plan, 3 different dose levels were prescribed: 68.4 Gy in 30 parts to gross tumor volume (GTV), 60 Gy in 30 parts to high‐risk clinical target volume (CTV), and 36 Gy in 18 parts to low‐risk CTV. In all patients, the initial 18 fractions were delivered by HT, and, after rival plan evaluation on the adaptive re‐plan, the later 12 fractions were delivered either by HT in 63 patients (64.3%, HT only) or IMPT in 35 patients (35.7%, HT/IMPT combination), respectively. Propensity‐score matching was conducted to control differences in patient characteristics. In all patients, grade ≥ 2 mucositis (69.8% vs 45.7%, P = .019) and grade ≥ 2 analgesic usage (54% vs 37.1%, P = .110) were found to be less frequent in HT/IMPT group. In matched patients, grade ≥ 2 mucositis were still less frequent numerically in HT/IMPT group (62.9% vs 45.7%, P = .150). In univariate analysis, stage IV disease and larger GTV volume were associated with increased grade ≥ 2 mucositis. There was no significant factor in multivariate analysis. With the median 14 month follow‐up, locoregional and distant failures occurred in 9 (9.2%) and 12 (12.2%) patients without difference by RT modality. In conclusion, comparable early oncologic outcomes with more favorable acute toxicity profiles were achievable by HT/IMPT combination in treating NPC patients.

A Systematic Review of Proton Therapy for the Management of Nasopharyngeal Cancer

“…All had at least 10 patients in the cohort and were entirely retrospective. Four studies were matched where patients receiving proton therapy were compared to patients receiving photon therapy [ 16 , 17 , 21 , 23 ]. Three used a mixed-beam approach with photons followed by a proton therapy boost [19, 21, 23,].…”

Early Clinical Outcomes of Intensity Modulated Radiation Therapy/Intensity Modulated Proton Therapy Combination in Comparison with Intensity Modulated Radiation Therapy Alone in Oropharynx Cancer Patients

“…We previously reported that the combination of IMRT and IMPT resulted in more advantageous acute side effect profiles with the equivalent oncologic outcomes [ 19 ]. To the best of our knowledge, there have been only a few retrospective studies on OPC patients, which evaluated the causal relationship between IMPT’s dosimetric advantage and RT-related toxicities.…”

“…In order to overcome this long waiting before treatment initiation, we developed our strategy to begin the RT course by IMRT (helical Tomotherapy, HT) and then to determine whether to continue IMRT or to switch into intensity modulated PBT (IMPT), based on the rival re-plan comparison, which corresponds to our adaptive re-plan policy. We previously reported the early clinical outcomes and acute toxicity profiles following IMRT only and IMRT/IMPT combination in treating nasopharynx cancer (NPC) patients [ 19 ], and now report our experience in treating OPC patients.…”

Early Clinical Outcomes by Combination of Intensity Modulated Radiation Therapy and Intensity Modulated Proton Therapy in Treating Oropharynx Cancer Patients

“…We previously reported the early clinical outcomes and acute toxicity profiles following IMRT only and IMRT/IMPT combination in treating the NPC patients [15], and found that combination of IMRT and IMPT was more advantageous in weight loss, analgesic use, with the equivalent oncologic outcomes. To the best of our knowledge, there have been only few retrospective studies on the OPC patients, which evaluated the causal relationship between of IMPT's dosimetric advantage and RT-related toxicities.…”

“…In order to overcome this long waiting before treatment initiation, we developed our strategy to begin the RT course by IMRT (helical Tomotherapy, HT) and then to determine whether to continue IMRT or to switch into intensity modulated PBT (IMPT), based on the rival re-plan comparison, which corresponds to our adaptive re-plan policy. We previously reported the early clinical outcomes and acute toxicity profiles following IMRT only and IMRT/IMPT combination in treating the nasopharynx cancer (NPC) patients [15], and would report our experience in treating the OPC patients.…”