“…Given the sharp dose gradients associated with IMPT, careful planning and consideration of plan robustness is essential to avoid risk of marginal recurrence. Reassuringly, LRC appears extremely high, and marginal recurrences are rare in our experience as well as in the several series that have been reported [ 16 , 35 ]. However, these results are early, and it has been recognized that recurrences from NPC may be seen from 3 to 5 years after treatment, so careful tracking of long-term outcomes will be important [ 7 ].…”
Section: Discussionsupporting
confidence: 70%
“…There were no grade 4 or 5 acute toxicities and no grade 3 or greater late toxicities. Jiri et al [ 35 ] recently reported a series of 40 patients with NPC treated with IMPT and 2-year LC was 84%. To our knowledge, our present experience represents the largest US single-institution report of IMPT for NPC.…”
Purpose
Advances in radiotherapy have improved tumor control and reduced toxicity in the management of nasopharyngeal carcinoma (NPC). Local failure remains a problem for some patients with advanced primary tumors, and toxicities are significant given the large treatment volume and tumor proximity to critical structures, even with modern photon-based radiotherapy. Proton therapy has unique dosimetric advantages, and recent technological advances now allow delivery of intensity-modulated proton therapy (IMPT), which can potentially improve the therapeutic ratio in NPC. We report our 2-year clinical outcomes with IMPT for NPC.
Materials and Methods
We retrospectively reviewed treatment records of patients with NPC treated with IMPT at our center. Demographics, dosimetry, tumor response, local regional control (LRC), distant metastasis, overall survival, and acute and late toxicity outcomes were reviewed. Analyses were performed with descriptive statistics and Kaplan-Meier method. Toxicity was graded per Common Terminology Criteria for Adverse Events (version 4.0).
Results
Twenty-six patients were treated from 2015 to 2020. Median age was 48 years (range, 19–73 years), 62% (n = 16) had T3-T4 disease, 92% (n = 24) were node positive, 92% (n = 24) had stage III-IV disease, and 69% (n = 18) had positive results for Epstein-Barr virus. Dose-painted pencil-beam IMPT was used. Most patients (85%; 22 of 26) were treated with 70 Gy(RBE) in 33 fractions once daily; 4 (15%) underwent hyperfractionated accelerated treatment twice daily. All received concurrent cisplatin chemotherapy; 7 (27%) also received induction chemotherapy. All patients (100%) completed the planned radiotherapy, and no acute or late grade 4 or 5 toxicities were observed. At median follow-up of 25 months (range, 4-60), there were 2 local regional failures (8%) and 3 distant metastases (12%). The Kaplan-Meier 2-year LRC, freedom from distant metastasis, and overall survival were 92%, 87%, and 85% respectively.
Conclusion
IMPT is feasible in locally advanced NPC with early outcomes demonstrating excellent LRC and favorable toxicity profile. Our data add to the growing body of evidence supporting the clinical use of IMPT for NPC.
“…Given the sharp dose gradients associated with IMPT, careful planning and consideration of plan robustness is essential to avoid risk of marginal recurrence. Reassuringly, LRC appears extremely high, and marginal recurrences are rare in our experience as well as in the several series that have been reported [ 16 , 35 ]. However, these results are early, and it has been recognized that recurrences from NPC may be seen from 3 to 5 years after treatment, so careful tracking of long-term outcomes will be important [ 7 ].…”
Section: Discussionsupporting
confidence: 70%
“…There were no grade 4 or 5 acute toxicities and no grade 3 or greater late toxicities. Jiri et al [ 35 ] recently reported a series of 40 patients with NPC treated with IMPT and 2-year LC was 84%. To our knowledge, our present experience represents the largest US single-institution report of IMPT for NPC.…”
Purpose
Advances in radiotherapy have improved tumor control and reduced toxicity in the management of nasopharyngeal carcinoma (NPC). Local failure remains a problem for some patients with advanced primary tumors, and toxicities are significant given the large treatment volume and tumor proximity to critical structures, even with modern photon-based radiotherapy. Proton therapy has unique dosimetric advantages, and recent technological advances now allow delivery of intensity-modulated proton therapy (IMPT), which can potentially improve the therapeutic ratio in NPC. We report our 2-year clinical outcomes with IMPT for NPC.
Materials and Methods
We retrospectively reviewed treatment records of patients with NPC treated with IMPT at our center. Demographics, dosimetry, tumor response, local regional control (LRC), distant metastasis, overall survival, and acute and late toxicity outcomes were reviewed. Analyses were performed with descriptive statistics and Kaplan-Meier method. Toxicity was graded per Common Terminology Criteria for Adverse Events (version 4.0).
Results
Twenty-six patients were treated from 2015 to 2020. Median age was 48 years (range, 19–73 years), 62% (n = 16) had T3-T4 disease, 92% (n = 24) were node positive, 92% (n = 24) had stage III-IV disease, and 69% (n = 18) had positive results for Epstein-Barr virus. Dose-painted pencil-beam IMPT was used. Most patients (85%; 22 of 26) were treated with 70 Gy(RBE) in 33 fractions once daily; 4 (15%) underwent hyperfractionated accelerated treatment twice daily. All received concurrent cisplatin chemotherapy; 7 (27%) also received induction chemotherapy. All patients (100%) completed the planned radiotherapy, and no acute or late grade 4 or 5 toxicities were observed. At median follow-up of 25 months (range, 4-60), there were 2 local regional failures (8%) and 3 distant metastases (12%). The Kaplan-Meier 2-year LRC, freedom from distant metastasis, and overall survival were 92%, 87%, and 85% respectively.
Conclusion
IMPT is feasible in locally advanced NPC with early outcomes demonstrating excellent LRC and favorable toxicity profile. Our data add to the growing body of evidence supporting the clinical use of IMPT for NPC.
“…As a future study, we are considering to add an indicator for re‐planning such as 5% weight loss in addition to the fixed adaptation course. Jiri et al have recently published initial clinical results of IMPT for NPC 30 . They used an individualized adaptive course that triggered the new plan when the target volume change reached some threshold, rather than a fixed fraction number.…”
Section: Discussionmentioning
confidence: 99%
“…Jiri et al have recently published initial clinical results of IMPT for NPC. 30 They used an individualized adaptive course that triggered the new plan when the target volume change reached some threshold, rather than a fixed fraction number. A larger than T A B L E 4 Dose volume parameters for OARs related to hearing in A-IMXT and A-IMPT plans.…”
Purpose: To investigate potential advantages of adaptive intensity-modulated proton beam therapy (A-IMPT) by comparing it to adaptive intensity-modulated X-ray therapy (A-IMXT) for nasopharyngeal carcinomas (NPC).Methods: Ten patients with NPC treated with A-IMXT (step and shoot approach) and concomitant chemotherapy between 2014 and 2016 were selected. In the actual treatment, 46 Gy in 23 fractions (46Gy/23Fx.) was prescribed using the initial plan and 24Gy/12Fx was prescribed using an adapted plan thereafter. New treatment planning of A-IMPT was made for the same patients using equivalent dose fractionation schedule and dose constraints. The dose volume statistics based on deformable images and dose accumulation was used in the comparison of A-IMXT with A-IMPT.
Results:The means of the D mean of the right parotid gland (P < 0.001), right TM joint (P < 0.001), left TM joint (P < 0.001), oral cavity (P < 0.001), supraglottic larynx (P = 0.001), glottic larynx (P < 0.001), , middle PCM (P = 0.0371), interior PCM (P < 0.001), cricopharyngeal muscle (P = 0.03643), and thyroid gland (P = 0.00216), in A-IMPT are lower than those of A-IMXT, with statistical significance. The means of, D 0.03cc , and D mean of each sub portion of auditory apparatus and D 30% for Eustachian tube and D 0.5cc for mastoid volume in A-IMPT are significantly lower than those of A-IMXT. The mean doses to the oral cavity, supraglottic larynx, and glottic larynx were all reduced by more than 20 Gy (RBE = 1.1).
“…The dosimetric superiority offered by protons' "Bragg peaks" enables it to better protect normal tissues while maintaining effective dose delivery to the tumor volume, in the irradiation for NPC. 18,19 Compared to IMRT, intensity-modulated proton radiation therapy (IMPT; the newest form of proton beam therapy) has been found to significantly reduce the normal tissue complication probability (NTCP) of key surrounding normal tissues including parotid glands, inner ears, larynx, oral cavity, and esophagus, thereby being considered to be a promising irradiation modality pursuing a better QoL for patients with NPC. [20][21][22][23] China, despite having the largest global NPC cases, has only one operational proton center but the government has authorized 16 new licenses for operating proton centers this year as a strategy for the "Healthy China" initiative.…”
Background: Compared to conventional intensity-modulated photon radiation therapy (IMRT), intensity-modulated proton radiation therapy (IMPT) has potential to reduce irradiation-induced late toxicities while maintaining excellent tumor control in patients with nasopharyngeal carcinoma (NPC). However, the relevant cost-effectiveness remains controversial.Methods: A Markov decision tree analysis was performed under the assumption that IMPT offered normal tissue complication probability reduction (NTCP reduction) in long-term dysphagia, xerostomia, and hearing loss, compared to IMRT. Base-case evaluation was performed on T2N2M0 NPC of median age (43 years old). A Chinese societal willingness-to-pay threshold
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