Feasibility of Selective Neck Irradiation with Lower Elective Radiation Dose in Treating Nasopharynx Cancer Patients

Optimizing Cervical Target Volume in Patients with Nasopharyngeal Cancer Based On Nodal Drainage Distance

PURPOSE

To determine the potential nodal drainage distances of nasopharyngeal carcinoma (NPC) by investigating spatial distribution of metastatic lymph nodes (LN).

EXPERIMENTAL DESIGN

Patients with NPC harboring at least two ipsilateral metastatic LNs were enrolled. LN spreading distances were analyzed in nonrestricted direction, cranial-to-caudal direction, and between the two most caudal LNs. Euclidean distance (ED) and vertical distance (VD) between any two LNs were computed. The nearest-neighbor ED and VD covering 95% of LNs or patients (p95-ED and p95-VD) were considered drainage distances, and were further validated by independent internal and external cohorts with recurrent LNs.

RESULTS

In all, 5,836 metastatic LNs in 948 patients were contoured. Corresponding to the three scenarios, per-LN level, the p95-EDs were 2.83, 3.28, and 3.55 cm, and p95-VDs were 2.17, 2.32, and 2.63 cm, respectively. Per-patient level, the p95-EDs were 3.25, 3.95, and 3.81 cm, and p95-VDs were 2.67, 2.81, and 2.73 cm, respectively. In internal validation, over 95% of recurred LNs occurred within ED of 2.91 cm and VD of 0.82 cm to the neighbor LN, and the corresponding distances in external validation were 2.77 and 0.67 cm, respectively.

CONCLUSIONS

In NPC, the maximum LN drainage distance was 3.95 cm without considering the direction. Specifically, in cranial-to-caudal direction, the sufficient vertical drainage distance was 2.81 cm, indicating that a 3-cm extension from the most inferior node may be rational as caudal border of the prophylactic clinical target volume (CTV). These findings promote in-depth understanding of nodal spreading patterns, uncovering paramount evidence for individualized CTV.

Can Definitive Radiation Therapy Substitute Surgical Resection in Locally Advanced T3 or T4 Sinonasal Squamous Cell Carcinoma?

PURPOSE

This study aimed to compare oncologic outcomes between definitive radiation therapy (RT) and upfront surgical resection in patients with sinonasal squamous cell carcinoma (SCC).

METHODS AND MATERIALS

Between 2008 and 2021, 155 patients with T1-4b, N0-3 sinonasal SCC were analyzed. The 3-year overall survival (OS), local progression-free survival (LPFS), and overall progression-free survival (PFS) were evaluated using the Kaplan Meier method and compared using a log-rank test. A pattern of regional neck lymph node (LN) failure and treatment-related toxicity profiles were investigated.

RESULTS

A total of 63 and 92 patients underwent upfront RT (RT group) and surgical resection (Surgery group), respectively. The RT group included significantly more patients with T3-4 disease than the Surgery group (90.5% vs 39.1%, P < .001). The rates of 3-year OS, LPFS, and PFS in the RT and Surgery groups were 68.6% versus 81.7% (P = .073), 62.3% versus 73.8% (P = .187), and 47.4% versus 66.1% (P = .005), respectively. However, the corresponding rates in patients with T3-4 disease were 65.1% versus 64.8% (P = .794), 57.4% versus 56.8% (P = .351), and 43.2% versus 46.5% (P = .638), respectively, demonstrating no statistically significant differences between the 2 treatment modalities. Among the 133 N0 patients, regional neck LN progression was observed in 17 patients, and the most common sites of regional neck LN failure were ipsilateral levels Ib (9 patients) and II (7 patients). The 3-year neck node recurrence-free rate in cT1-3N0 patients was 93.5%, while that in cT4N0 patients was 81.1% (P = .025).

CONCLUSIONS

Upfront RT may be considered in selected patients with locally advanced sinonasal SCC, as we have demonstrated similar oncologic outcomes to those of surgery. Prophylactic neck treatment in T4 disease requires further investigation to evaluate its efficacy.

The Metabolic Footprint of Systemic Effects in the Blood Caused by Radiotherapy and Inflammatory Conditions: A Systematic Review

Response to radiotherapy (RT) includes tissue toxicity, which may involve inflammatory reactions. We aimed to compare changes in metabolic patterns induced at the systemic level by radiation and inflammation itself. Patients treated with RT due to head and neck cancer and patients with inflammation-related diseases located in the corresponding anatomical regions were selected. PubMed and Web of Science databases were searched from 1 January 2000 to 10 August 2023. Twenty-five relevant studies where serum/plasma metabolic profiles were analyzed using different metabolomics approaches were identified. The studies showed different metabolic patterns of acute and chronic inflammatory diseases, yet changes in metabolites linked to the urea cycle and metabolism of arginine and proline were common features of both conditions. Although the reviewed reports showed only a few specific metabolites common for early RT response and inflammatory diseases, partly due to differences in metabolomics approaches, several common metabolic pathways linked to metabolites affected by radiation and inflammation were revealed. They included pathways involved in energy metabolism (e.g., metabolism of ketone bodies, mitochondrial electron transport chain, Warburg effect, citric acid cycle, urea cycle) and metabolism of certain amino acids (Arg, Pro, Gly, Ser, Met, Ala, Glu) and lipids (glycerolipids, branched-chain fatty acids). However, metabolites common for RT and inflammation-related diseases could show opposite patterns of changes. This could be exemplified by the lysophosphatidylcholine to phosphatidylcholine ratio (LPC/PC) that increased during chronic inflammation and decreased during the early phase of response to RT. One should be aware of dynamic metabolic changes during different phases of response to radiation, which involve increased levels of LPC in later phases. Hence, metabolomics studies that would address molecular features of both types of biological responses using comparable analytical and clinical approaches are needed to unravel the complexities of these phenomena, ultimately contributing to a deeper understanding of their impact on biological systems.

Involved site radiation therapy in stage I-III nasopharyngeal carcinoma with limited lymph node burden (ISRT-NPC) or elective region irradiation: a study protocol for a multicenter non-inferiority randomized controlled phase III clinical trial

BACKGROUND

Current radiotherapy guidelines and consensus statements uniformly recommend elective region irradiation (ERI) as the standard strategy for nasopharyngeal carcinoma (NPC). However, given the scarcity of skip-metastasis, the improved assessment accuracy of nodal involvement, and the striking advancements in chemotherapy for NPC, a one-fits-all delineation scheme for clinical target volumes of the nodal region (CTVn) may not be appropriate anymore, and modifications of the CTVn delineation strategy may be warranted. Involved site irradiation (ISI) covering merely the initially involved nodal site and potential extranodal extension has been confirmed to be as effective as ERI with decreased radiation-related toxicities in some malignancies, but has not yet been investigated in NPC. This study aims to compare the regional control, survival outcomes, radiation-related toxicities, and quality of life (QoL) of ISI with conventional ERI in NPC patients with a limited nodal burden.

METHODS

ISRT-NPC is a prospective, multicenter, open-label, noninferiority, phase III randomized controlled trial. A total of 414 patients will be randomly assigned in a 1:1 ratio to receive ISI or ERI. Randomization will be stratified by institution scale and N stage. Generally, in the ISI group, the high-risk CTV1 (dose: 60 Gy) includes a 1-cm expansion of the positive LN as well as the VIIa and the retrostyloid space above the bilateral transverse process of the atlantoaxial spine (C1), regardless of N status. The low-risk CTV2 (dose: 50 Gy) covers the cervical nodal region with a 3-cm caudal expansion below the transverse process of C1 for N0 disease and a 3-cm expansion below the positive LN for positive LNs.

DISCUSSION

The results of this trial are expected to confirm that ISI is a non-inferior strategy to ERI in stage I-III patients with low LN burden, enabling the minimization of treatment-related toxicity and improvement of long-term QoL without compromising regional control.

TRIAL REGISTRATION

ClinicalTrails.gov, NCT05145660. Registered December 6, 2021.

DOSE AND VOLUME DE-ESCALATION OF RADIOTHERAPY IN HEAD AND NECK CANCER

Radiotherapy plays a key role in the treatment of head and neck cancer. However, irradiation of the head and neck region is associated with high rates of acute and chronic toxicity. Technological advances have led to better visualisation of target volumes and critical structures and improved dose conformality in the treatment volume. Despite this, acute toxicity has not been substantially reduced and late toxicity has a significant impact on patients' quality of life. The greater radiosensitivity of tumours associated with the HPV and the development of new imaging techniques have encouraged research into new deintensified strategies to reduce the side effects of radiotherapy. The aim of this paper is to review the literature on the strategies of de-escalated treatment in dose and/or volume in head and neck cancer.

High Superior-Middle Pharyngeal Constrictor Muscle Mean Dose Correlates with Severe Late Lung Infection and Survival in Nasopharyngeal Cancer Patients

Purpose

The study aimed to evaluate 1) the correlation of doses of swallowing-related organs at risk (OAR) with severe swallowing-related late adverse effects (AE) in nasopharyngeal carcinoma (NPC) patients and 2) the effect of high mean doses of OARs on overall survival (OS).

Patients and Methods

This retrospective cohort study enrolled non-metastatic Stage I–IV NPC patients from January 2012 to June 2017. OAR mean doses and severe (≥G3) swallowing-related late AE (xerostomia, dysphagia, and lung infection) were evaluated by t-test and validated using receiver operating characteristic curves. The risk factors of OS were calculated by Cox regression methods.

Results

This study enrolled 185 (43 female, 142 male) NPC patients, mean age 52.4 years, primarily with Stage III (93, 50.3%) or Stage IV (67, 36.2%) disease. The mean doses of pharyngeal constrictor muscle (PCM), superior-middle PCM (SMPCM), and superior PCM (SPCM) were significantly higher in those with severe (≥G3) lung infection than in those without (65.7 vs 62.2 Gy, p = 0.036; 68.1 vs 64.2 Gy, p = 0.015; and 70.0 vs 65.9 Gy, p = 0.012, respectively). Patients with severe (≥G3) dysphagia had significant higher mean doses of base of tongue (56.2 vs 50.2 Gy, p = 0.008), laryngeal box (50.6 vs 46.4 Gy, p = 0.036), PCM (65.4 vs 62.1 Gy, p = 0.008), SMPCM (67.1 vs 64.2 Gy, p = 0.014), and SPCM (69.3 vs 65.8 Gy, p = 0.004). Mean SMPCM dose >64.9 Gy (adjusted hazard ratio [aHR] = 3.2, 95% confidence interval [CI] 1.2–8.8, p = 0.021), age >62 years (aHR = 2.7, 95% CI 1.1–6.9, p = 0.032), N3 status (aHR = 4.0, 95% CI 1.8–9.0, p = 001), and severe late AE of lung infection (aHR = 4.6, 95% CI 1.5–14.0, p = 0.007) significantly affected OS.

Conclusion

Severe lung infection and dysphagia were associated with significantly higher mean doses of PCM, SMPCM, and SPCM. Among these OARs, only a high SMPCM mean dose was a risk factor for OS in NPC patients.

Risk of Stroke in Nasopharyngeal Cancer Survivors: A National Registry-Based Population Cohort Study

BackgroundWe aim to determine the risk of stroke and death within 30 days post stroke in nasopharyngeal cancer (NPC) survivors.MethodsWe conducted a population-based cohort study of patients diagnosed with NPC from Jan 1, 2005 to Dec 31, 2017. Using the cancer and stroke disease registries and the Singapore general population as the reference population, we report the age-standardized incidence rate differences (SIRDs) ratios (SIRs) and the cumulative incidence of stroke and the standardized mortality rate differences (SMRDs) and ratios (SMRs) for all causes of death within 30 days post stroke for NPC survivors.FindingsAt a median follow up of 48.4 months (IQR 19.8 - 92.9) for 3849 patients diagnosed with NPC, 96 patients developed stroke. The overall SIRD and SIR for stroke was 3.12 (95% CI 2.09 - 4.15) and 2.54 (95% CI 2.08 - 3.10) respectively. The SIRD was highest for the age group 70 - 79 years old (8.84 cases per 1000 person-years (PY); 0.46 - 17.21) while the SIR was highest for the age group 30 - 39 years old (16.41; 6.01 - 35.82). The SIRD and SIR for stage 1 disease was (6.96 cases per 1000 PY; 2.16 - 11.77) and (4.15; 2.46 - 7.00) respectively. The SMRD and SMR for all cause deaths within 30 days of stroke was (3.20 cases per 100 persons; -3.87 - 10.28) and (1.34; 0.76 - 2.37) respectively.InterpretationThe overall risk of stroke was markedly elevated in survivors of NPC, especially in Stage 1 disease when compared to the general population. The risk of death within 30 days of stroke was not significantly higher for NPC survivors.Classification of EvidenceThis study provides Class II evidence of the increased risk of stroke in survivors of nasopharyngeal cancer compared to general population.

Contemporary management of the neck in nasopharyngeal carcinoma

Up to 85% of the patients with nasopharyngeal carcinoma present with regional nodal metastasis. Although excellent nodal control is achieved with radiotherapy, a thorough understanding of the current TNM staging criteria and pattern of nodal spread is essential to optimize target delineation and minimize unnecessary irradiation to adjacent normal tissue. Selective nodal irradiation with sparing of the lower neck and submandibular region according to individual nodal risk is now emerging as the preferred treatment option. There has also been continual refinement in staging classification by incorporating relevant adverse nodal features. As for the uncommon occurrence of recurrent nodal metastasis after radiotherapy, surgery remains the standard of care.

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

Simple Summary

Intensity-modulated proton therapy (IMPT) is expected to reduce toxicity more effectively than intensity-modulated radiation therapy (IMRT) in treating oropharynx cancer (OPC) patients. Because of long waiting before starting IMPT, authors began IMRT first and then determined whether to continue IMRT or to switch into IMPT at time of adaptive re-plan, based on the rival plan comparison in 148 OPC patients. Early clinical outcomes were analyzed and compared between IMRT alone and IMRT/IMPT combination groups through propensity score matching method. We found that, with comparable oncologic outcomes, more favorable acute toxicity profiles (mucositis and need for analgesic use) were achieved following IMRT/IMPT combination than IMRT alone.

Abstract

Purpose: To report the early clinical outcomes of combining intensity-modulated radiation therapy (IMRT) and intensity-modulated proton therapy (IMPT) in comparison with IMRT alone in treating oropharynx cancer (OPC) patients. Materials and Methods: The medical records of 148 OPC patients who underwent definitive radiotherapy (RT) with concurrent systemic therapy, from January 2016 till December 2019 at Samsung Medical Center, were retrospectively reviewed. During the 5.5 weeks’ RT course, the initial 16 (or 18) fractions were delivered by IMRT in all patients, and the subsequent 12 (or 10) fractions were either by IMRT in 81 patients (IMRT only) or by IMPT in 67 (IMRT/IMPT combination), respectively, based on comparison of adaptive re-plan profiles and availability of equipment. Propensity-score matching (PSM) was done on 76 patients (38 from each group) for comparative analyses. Results: With the median follow-up of 24.7 months, there was no significant difference in overall survival and progression free survival between groups, both before and after PSM. Before PSM, the IMRT/IMPT combination group experienced grade ≥ 3 acute toxicities less frequently: mucositis in 37.0% and 13.4% (p < 0.001); and analgesic quantification algorithm (AQA) in 37.0% and 19.4% (p = 0.019), respectively. The same trends were observed after PSM: mucositis in 39.5% and 15.8% (p = 0.021); and AQA in 47.4% and 21.1% (p = 0.016), respectively. In multivariate logistic regression, grade ≥ 3 mucositis was significantly less frequent in the IMRT/IMPT combination group, both before and after PSM (p = 0.027 and 0.024, respectively). AQA score ≥ 3 was also less frequent in the IMRT/IMPT combination group, both before and after PSM (p = 0.085 and 0.018, respectively). Conclusions: In treating the OPC patients, with comparable early oncologic outcomes, more favorable acute toxicity profiles were achieved following IMRT/IMPT combination than IMRT alone.

Re-irradiation with Moderate Hypo-Fractionation Using Intensity Modulated Photon or Proton Radiation Therapy in Locally Recurrent Squamous Cell Carcinoma of Nasopharynx

Purpose

This study aimed to analyze the treatment outcomes of locally recurrent nasopharyngeal cancer (NPC) patients following moderate hypo-fractionation re-irradiation (re-RT).

Materials and Methods

Sixty locally recurrent NPC patients underwent hypo-fractionation re-RT. 48.3% had rT3-4, and 30.0% did keratinizing squamous cell carcinoma. Intensity-modulated radiation therapy (IMRT), with or without intensity-modulated proton therapy (IMPT), was used in 66.7% of patients.

Results

With the median follow up of 22 (2~254) months, 31 patients (51.7%) died, 38 (63.3%) developed further treatment failure, and 30 (50.0%) developed ≥Grade 3 toxicity (including seven Grade 5) at time of analysis. The 2- and 5-year rates of overall survival, local failure-free survival, and ≥Grade 3 toxicity-free survival were 57.9% and 45.8%, 64.1% and 52.5%, and 54.8% and 44.9%, respectively. In multivariate analyses, worse factors for OS were iT3-4 (p=0.010) and age at re-RT ≥53 years (p=0.003), those for LFFS were rT3-4 (p=0.022) and rN0-1 (p=0.035), and those for TFS were iT3-4 (p=0.020) and rIMRT/IMPT (p=0.030), respectively. Cumulative dose or fraction size ≥3 Gy at re-RT, however, showed no significance for OS, LFFS and TFS.

Conclusion

Current re-RT with modern RT techniques by moderate hypo-fractionation scheme seemed feasible in treating locally recurrent NPC patients.

Oncological and Functional Outcomes of Larynx-preserving Surgery for Hypopharyngeal Cancer: A Comparison with Definitive Radiation-based Treatment

Purpose

Larynx-preserving surgery (LPS) have recently gained popularity and achieved comparable oncologic outcomes to conventional radical surgery for localized hypopharyngeal cancer (HPC). In the current study, the role of LPS has been assessed thoroughly in comparison with upfront radiation therapy (RT).

Materials and Methods

We retrospectively reviewed 185 candidates for LPS with cT1–2 disease; 59 patients underwent upfront LPS while 126 patients received upfront RT, respectively. Oncological and functional outcomes were investigated and compared.

Results

Following LPS, safe margin (≥ 5 mm) was achieved in 37.3% of patients. Overall, better clinical outcomes at 5 years were achieved following upfront LPS than those following upfront RT: overall survival (OS) (72.7% vs. 59.0%, p=0.045), disease-free survival (DFS) (59.8% vs. 45.0%, p=0.039), and functional laryngeal preservation (100% vs. 89.7%, p=0.010). Although similar outcomes were observed in patients with cT1 disease, better 5-year DFS was achieved following upfront LPS in patients with cT2 disease (57.0% vs. 36.4%, p=0.023) by virtue of better local control. Despite frequent cN2–3 disease in upfront LPS group, comparable outcomes were observed between upfront RT and LPS group. However, multivariable analyses revealed that performance status and double primary cancer diagnosed within 6 months of HPC diagnosis affected OS significantly, while treatment modality per se did not.

Conclusion

Although upfront LPS could provide better local control than upfront RT in patients with cT2 disease, overall outcomes were comparable following either modality. Treatment selection of larynx-preserving approach for HPC should be individualized based on tumor and patient factors.

Clinical features of post-radiation nasopharyngeal necrosis and their outcomes following surgical intervention in nasopharyngeal cancer patients

PURPOSE

To investigate the incidence and clinical features of post-radiation nasopharyngeal necrosis (PRNN), and effectiveness of surgical intervention for its treatment.

MATERIALS AND METHODS

Retrospectively, we reviewed 380 NPC patients who underwent high dose radiotherapy (RT) (single RT in 355 and re-RT in 25) from January 2008 till December 2017 at the authors' institute, among who 22 developed Grade ≥ 3 PRNN. The management of PRNN was discussed through weekly multidisciplinary head and neck oncology conference, and surgical debridement was performed when feasible.

RESULTS

The incidence of PRNN was significantly higher following re-RT than in single RT (11/355, 3.1% vs. 11/25, 44.0%, p < 0.001). The PRNN patients in single RT group tended to be older and had more advanced initial tumor extents. The intervals from the latest RT start till PRNN assignment were similar between groups (7.3 vs. 6.6 months, p = 0.140). Nineteen patients underwent surgical debridement: two open; and 17 endoscopic approach, respectively. Endoscopic mucosal reconstruction was performed in eight patients. Resolution of PRNN was achieved in 11 patients (64.7%). The rates of 3-year overall survivals (OS) from the initial RT, latest RT (adjusting re-RT), and PRNN assignment were 84.4%, 70.9%, and 54.7%, respectively. Eight patients (36.4%) succumbed to death: NPC progression in three (13.6%); evidently PRNN-related events in two (9.1%), probably PRNN-related events in two (9.1%); and inter-current death in one (4.5%), respectively.

CONCLUSION

PRNN needs close collaboration among head and neck oncologists and could be successfully recovered, without compromising survival, following timely surgical intervention.

Development and Validation of Web-Based Nomograms to Precisely Predict Survival Outcomes of Non-metastatic Nasopharyngeal Carcinoma in an Endemic Area

Purpose

This study aimed to develop web-based nomograms to precisely predict survival outcomes in patients with non-metastatic nasopharyngeal carcinoma (NPC) in an endemic area.

Materials and Methods

A total of 10,126 patients who underwent radical intensity-modulated radiotherapy at Sun Yat-sen University Cancer Center (SYSUCC) from 2009 to 2015 were analyzed. We assigned patients into a training cohort (SYSUCC-A, n=6,751) and an internal validation cohort (SYSUCC-B, n=3,375) based on computer-generated random numbers. Patients collected from Wuzhou Red Cross Hospital (WZRCH) between 2012 and 2015 were used as the independent external validation cohort (WZRCH, n=450). Concordance index (C-index) was used to determine predictive accuracy and discriminative ability for the nomogram. The web-based clinicopathologic prediction models for predicting survival were based on Cox regression.

Results

The C-indexes for SYSUCC-A, SYSUCC-B, and WZRCH cohorts for the established nomograms to predict 3-year overall survival (OS) was 0.736, 0.715, and 0.691. Additionally, C-indexes to predict 3-year distant metastasis-free survival (DMFS) was 0.717, 0.706, and 0.686, disease-free survival (DFS) was 0.713, 0.697, and 0.656, local relapse-free survival was 0.695, 0.684, and 0.652, and regional relapse-free survival was 0.672, 0.650, and 0.616. The calibration plots showed great agreement between nomogram-predicted 3-year survival outcomes and actual 3-year survival outcomes. Moreover, C-indexes of the nomograms for OS, DMFS, and DFS were significantly superior than TNM stage (p < 0.001 for all).

Conclusion

These user-friendly nomograms can precisely predict survival endpoints in patients with non-metastatic NPC. They may serve as a useful tool for providing patient counseling and help physicians to make individual follow-up plans.

Simultaneous Reduction of Volume and Dose in Clinical Target Volume for Nasopharyngeal Cancer Patients

PURPOSE

To compare the treatment outcome and severe late adverse effects (AEs) between conventional volume and dose (CVD) and simultaneously reduced volume and dose (SRVD) of clinical target volume treatments in patients with nasopharyngeal carcinoma.

METHODS AND MATERIALS

This retrospective cohort study enrolled patients with nonmetastatic stage II to IV nasopharyngeal cancer from a single institute. Survival endpoints and severe (≥grade 3) late AEs and comorbidity were compared between groups. The correlation of severe late AEs, comorbidity, and overall survival (OS) were evaluated using Kaplan-Meier and Cox regression methods.

RESULTS

From January 2012 to June 2017, this study enrolled 178 patients, 64 in the CVD group and 114 in the SRVD group. The 2 groups did not differ significantly in patient characteristics except for mean follow-up time (37.6 vs 48.8 months; P = .01). The SRVD group did not significantly differ from the CVD group in local control survival (82.0% vs 78.4%; P = .85), regional control survival (89.9% vs 86.0%; P = .62), or disease-free survival (76.4% vs 66.9%; P = .67). The SRVD group had significantly better OS (93.9% vs 67.0%; P < .001) and salvage survival (79.3% vs 20.7%; P < .01) and a significantly lower ratio of severe lung infection (1 of 113 vs 5 of 59; P = .02). The SRVD group had a significantly lower risk of mortality (hazard ratio [HR], 0.3; P = .03). The factors associated with a significantly higher risk of mortality were N3 (regional lymph node stage status of N3) (HR, 3.0; P = .02); comorbidities of diabetes, coronary artery disease, or chronic kidney disease (grades 2-3) (HR, 3.8; P = .009), and severe lung infection (HR, 6.3; P = .007).

CONCLUSIONS

Simultaneously reduced volume and dose of clinical target volumes did not impair locoregional control or disease-free survival. The benefits of SRVD treatment may include significant reduction in severe late AEs, particularly lung infection, dysphagia, and xerostomia. However, additional studies with longer patient follow-up are required to confirm these benefits.

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

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.