Experience in fractionated stereotactic body radiation therapy boost for newly diagnosed nasopharyngeal carcinoma

Stereotactic ablative radiotherapy for treating primary head and neck cancer and locoregional recurrence: A comprehensive review of the literature

Introduction

Although stereotactic ablative radiotherapy (SABR) has advance to standard-of-care for many different indications like lung and liver malignancies, it still remains in its infancy for treating head and neck cancer. Nevertheless there is a growing body of experience and evidence, which is summarized in this review Methods A thorough search of the literature was performed and critically reviewed both for SABR as a primary treatment as well as for treating locoregionally recurrent disease in a pre-irradiated field.

Results

There exist only few prospective data published so far for treating head and neck cancer with SABR. In the primary situation especially implementing SABR as a boost after definitive radiotherapy or a single-modality for locally limited, small glottic cancer appear promising. On the other hand, SABR can be a useful modality for treating local recurrence in a pre-irradiated field. However, caution is needed in the case of proximity to a pre-irradiated carotid artery or other serial organs at risk. Usually only limited gross volumes are treated with 3-6 fractions every other day and a cumulative dose of 24-44 Gy in dedicated radiosurgery platforms or modern linacs with the possibility of online image-guidance and adequate immobilsation.

Conclusions

SABR is an innovative, effective and promising treatment modality for small targets, especially in near proximity to organs at risk or in a pre-irradiated region. Prospective trials are further needed for this technique to become standard-of care.

The Evolving Role of Stereotactic Body Radiation Therapy for Head and Neck Cancer: Where Do We Stand?

Stereotactic body radiation therapy (SBRT) is a precise and conformal radiation therapy (RT) that aims to deliver a high dose of radiation to the tumor whilst sparing surrounding normal tissue, making it an attractive option for head and neck cancer (HNC) patients who are not suitable for the traditional long course of RT with comprehensive RT target volume. Definitive SBRT for HNC has been investigated in different settings, including early stage glottis cancer, and as an alternative to brachytherapy boost after external beam RT. It is also used as a primary treatment option for elderly or medically unfit patients. More recently, an SBRT combination with immunotherapy in the neoadjuvant setting for HNC showed promising results. Salvage or adjuvant SBRT for HNC can be used in appropriately selected cases. Future studies are warranted to determine the optimum dose and fractionation schedules in any of these indications.

Escalating a Biological Dose of Radiation in the Target Volume Applying Stereotactic Radiosurgery in Patients with Head and Neck Region Tumours

Background: The treatment of head and neck tumours is a complicated process usually involving surgery, radiation therapy, and systemic treatment. Despite the multidisciplinary approach, treatment outcomes are still unsatisfactory, especially considering malignant tumours such as squamous cell carcinoma or sarcoma, where the frequency of recurrence has reached 50% of cases. The implementation of modern and precise methods of radiotherapy, such as a radiosurgery boost, may allow for the escalation of the biologically effective dose in the gross tumour volume and improve the results of treatment. Methods: The administration of a stereotactic radiotherapy boost can be done in two ways: an upfront boost followed by conventional radio(chemo)therapy or a direct boost after conventional radio(chemo)therapy. The boost dose depends on the primary or nodal tumour volume and localization regarding the organs at risk. It falls within the range of 10–18 Gy. Discussion: The collection of detailed data on the response of the disease to the radiosurgery boost combined with conventional radiotherapy as well as an assessment of early and late toxicities will contribute crucial information to the prospective modification of fractionated radiotherapy. In the case of beneficial findings, the stereotactic radiosurgery boost in the course of radio(chemo)therapy in patients with head and neck tumours will be able to replace traditional techniques of radiation, and radical schemes of treatment will be possible for future development.

Stereotactic radiotherapy as planned boost after definitive radiotherapy for head and neck cancers: Systematic review

Management of locoregionally advanced head and neck cancers (HNCs) remains a challenge. Some groups have attempted to use stereotactic radiotherapy (SBRT) to deliver "boost" treatment following conventional radiotherapy to improve local control (LC) and overall survival (OS), while aiming for acceptable toxicities. Medline, EMBASE, and Cochrane Library databases were queried for SBRT as curative-intent planned boost in HNC after conventional radiotherapy. Individual studies were reviewed from inception until January 2021, extracting patient, treatment, and outcome data. Nine studies met inclusion criteria, representing 454 unique patients treated with curative intent across multiple head and neck sites with conventional radiotherapy. At 3 years, median LC was 92% (90%-98%), and median OS was 80% (75%-91%). Seven treatment-related grade 5 toxicities (1.5%) were reported. Despite acceptable LC and OS rates, there were severe treatment-related late toxicities. As such, SBRT boost should only be used in investigational settings until more data is available.

Stereotactic body radiotherapy (SBRT) for primary non-metastatic head and neck cancer: When less is enough

The advantage of highly conformal dose distribution and steep dose gradient has resulted in rapidly increasing use of stereotactic body radiotherapy (SBRT) in multiple cancer sites. Also there has been a surge in the use of SBRT in head neck cancer over the last decade. It is predominantly exploited in retreatment setting for recurrent and second primary head neck cancer as well as in metastatic setting. The literature on SBRT in primary non-metastatic head neck cancer is sparse and evolving. In the current review, available literature was critically analyzed focusing on the potential applications of SBRT in primary untreated non-metastatic head neck cancer. SBRT boost following external beam radiotherapy is temping as a method of dose escalation. Special attention was paid to the application of SBRT as a sole modality of treatment. The shorter treatment schedule makes it an attractive option for treatment in primary head neck cancer especially in elderly, co-morbid and medically unfits patients. Future investigation is needed to establish SBRT as an additional armamentarium in the radiotherapeutic management of head and neck cancers.

Phase I trial of dose-escalated stereotactic radiosurgery (SRS) boost for unfavorable locally advanced oropharyngeal cancer

Background and purpose

Patients with locally advanced oropharynx squamous cell carcinoma have suboptimal outcomes with standard chemoradiation. Here, we evaluated toxicity and oncologic outcomes of dose escalation using radiosurgical boost for patients with unfavorable oropharynx squamous cell carcinoma.

Materials and methods

Between 2010–2017, Thirty four patients with intermediate- or high-risk oropharynx squamous cell carcinoma were enrolled onto this prospective phase I trial. Each patient received concurrent cisplatin and fractionated radiotherapy totaling 60 Gy or 66 Gy followed by radiosurgery boost to areas of residual gross tumor: single fraction of 8 Gy or 10 Gy, or two fractions of 5 Gy each. Primary endpoint was treatment toxicity. Secondary endpoints were local, regional, and distant disease control.

Results

Eleven, sixteen and seven patients received radiosurgery boost with 8 Gy in 1 fraction, 10 Gy in 1 fraction, and 10 Gy in 2 fractions respectively. Acute toxicities include 4 patients with tumor necrosis causing grade 3 dysphagia, of which 3 developed grade 4 pharyngeal hemorrhage requiring surgical intervention. At 24 months after treatment, 7%, 9%, and 15% had grade 2 dysgeusia, xerostomia, and dysphagia, respectively, and two patients remained feeding tube dependent. No grade 5 toxicities occurred secondary to treatment. Local, regional, and distant control at a median follow up of 4.2 years were 85.3%, 85.3% and 88.2%, respectively. Five patients died resulting in overall survival of 85.3%.

Conclusions

This study is the first to report the use of radiosurgery boost dose escalation in patients with unfavorable oropharynx squamous cell carcinoma. Longer follow-up, larger cohorts, and further refinement of boost methodology are needed prior to implementation in routine clinical practice.

Trial Registration: Northwell Health Protocol #09-309A (NCT02703493) (https://clinicaltrials.gov/ct2/show/NCT02703493)

[Technical aspects and indications of extracranial stereotactic radiotherapy]

Extracranial stereotactic radiotherapy has developed considerably in recent years and is now an important part of the therapeutic alternatives to be offered to patients with cancer. It offers opportunities that have progressively led physicians to reconsider the therapeutic strategy, for example in the case of local recurrence in irradiated territory or oligometastatic disease. The literature on the subject is rich but, yet, there is no real consensus on therapeutic indications. This is largely due to the lack of prospective, randomized studies that have evaluated this technique with sufficient recoil. We propose a review of the literature on the technical aspects and indications of extracranial stereotactic radiotherapy.

Stereotactic body radiotherapy for head and neck cancer: an addition to the armamentarium against head and neck cancer

In the recent years, stereotactic body radiation therapy (SBRT) has emerged as a potential therapy for head and neck malignancies. Although early results appear to be promising, serious acute and late effects have been observed, mainly in patients who have had prior external beam radiotherapy. This review will discuss the radiobiology of SBRT, clinical rationale and outcomes for SBRT in head and neck cancers and focus on the benefits and potential limitations in both de novo and re-irradiation settings.

Comparison of concurrent chemoradiotherapy versus neoadjuvant chemotherapy followed by radiation in patients with advanced nasopharyngeal carcinoma in endemic area: experience of 128 consecutive cases with 5 year follow-up

Background

Combined radiotherapy and chemotherapy is considered the standard of care for locally advanced nasopharyngeal carcinoma (LA-NPC) in Epstein-Barr virus infection endemic area. This study compared the long-term outcomes between LA-NPC patients treated with neoadjuvant chemotherapy followed by radiotherapy (NACT) and those treated with concurrent chemoradiotherapy (CCRT).

Methods

From 2003 to 2007, a total of 128 histopathologically proven LA-NPC patients receiving either NACT or CCRT were consecutively enrolled at the National Cheng Kung University Hospital in Taiwan. NACT consisted of 3-week cycles of mitomycin, epirubicin, and cisplatin on day 1 and fluorouracil and leucovorin on day 8 (MEPFL) or weekly alternated cisplatin on day 1 and fluorouracil and leucovorin on day 8 (P-FL). CCRT comprised 3-week cycles of cisplatin (Cis 100) or 4-week cycles of cisplatin and fluorouracil (PF4). The first failure site, disease free survival (DFS), overall survival (OS), and other prognostic factors were analyzed.

Results

Thirty-eight patients (30%) received NACT. Median follow-up duration was 53 months. More patients with advanced nodal disease (N2-N3) (86.8% vs 67.8%, p =0.029) and advanced clinical stage (stage IVA-IVB) enrolled in the NACT group (55.2% vs 26.7%, p =0.002). For NACT, both MEPFL and P-FL had similar 5-year DFS and OS (52.9% vs 50%, p =0.860 and 73.5% vs 62.5%, p =0.342, respectively). For CCRT, both PF4 and Cis 100 had similar 5-year DFS and OS (62.8% vs 69.6%, p =0.49 and 72.9% vs 73.9%, p =0.72, respectively). Compared to CCRT, NACT had similar 5-year DFS and OS (51.5% vs 65.1%, p =0.28 and 71.7% vs 74.3%, p =0.91, respectively). Among patients who were recurrence-free in the first 2 years after treatment, those treated with NACT experienced poorer locoregional control compared to those treated with CCRT (Hazard ratio =2.57, 95% confidence interval: 1.02 to 6.47, p =0.046).

Conclusions

For LA-NPC, both CCRT and NACT were similarly efficacious treatment strategies in terms of long-term disease control and survival probability. Close locoregional follow-up is recommended for patients receiving NACT, because these patients are more prone to develop locoregional failure than patients receiving CCRT.

Preliminary results of a phase I/II study of simultaneous boost irradiation radiotherapy for locally advanced nasopharyngeal carcinoma

BACKGROUND

The purpose of this article is to present preliminary results of simultaneous boost irradiation radiotherapy for locally advanced nasopharyngeal carcinoma (NPC).

METHODS

Fifty-eight patients who underwent simultaneous boost irradiation radiotherapy for NPC in Cancer Center of Sun Yat-sen University between September 2004 and December 2009 were eligible. Acute and late toxicities were scored weekly according to the Radiation Therapy Oncology Group (RTOG) acute and late radiation morbidity scoring schemes. An especial focus was on evidence of post-radiation brain injury. Also quality of life was analysed according to the EORTC (European Organisation for Research and Treatment of Cancer) recommendations. Discrete variables were compared by ?2 test. The Kaplan-Meier method was used to calculate the survival rates and generate survival curves.

RESULTS

A total of 58 patients with a mean follow-up time of 36 months completed clinical trials.Fifty- seven patients (98.3) achieved complete remission in the primary sites and cervical lymph nodes, with only one patient (1.7%) showing partial remission.The most frequently observed acute toxicities during the concurrent chemoradiotherapy were mucositis and leucopenia. Four patients (6.9%) had RTOG grade 3 mucositis, whereas four patients (6.9%) had grade 3 leucopenia. No patient had grade 4 acute toxicity. Three (5.17%) of the patients exhibited injury to the brain on routine MRI examination, with a median observation of 32 months (range, 25-42months). All of them were RTOG grade 0. The 3-year overall, regional-free and distant metastasis-free survival rates were 85%, 94% and 91%, respectively.

CONCLUSION

Simultaneous boost irradiation radiotherapy is feasible in patients with locally advanced nasopharyngeal carcinoma. The results showed excellent local control and overall survival, with no significant increase the incidence of radiation brain injury or the extent of damage. A larger population of patients and a longer follow-up period are needed to evaluate ultimate tumor control and late toxicity.

Late toxicities after intensity-modulated radiotherapy for nasopharyngeal carcinoma: patient and treatment-related risk factors

Background:

The objective of this study is to analyse the factors affecting late toxicity for nasopharyngeal carcinoma (NPC) patients treated with intensity-modulated radiotherapy (IMRT).

Methods:

Seven hundred and eighty-nine consecutive NPC patients treated with IMRT at our centre from January 2003 to February 2008 were retrospectively analysed. Radiotherapy-related complications were categorised using the RTOG Late Radiation Morbidity Scoring Criteria and the Common Terminology Criteria for Adverse Events (Version 3.0). Two hundred and thirty-three patients were treated with IMRT alone (group 1) and 556 patients underwent cisplatin-based chemotherapy (group 2).

Results:

Median follow-up was 65 months (range, 4–106 months). The 5-year major late toxicity rate was significantly greater in group 2 than group 1 (63.2% vs 42.0%, P<0.001). Multivariate analyses showed that N category, T category and chemotherapy were significant factors. The maximal dose (Dmax) to the temporal lobe was a significant factor affecting temporal lobe injury (TLI), with a hazard ratio of 1.26 (95% confidence interval (CI), 1.18–1.35; P<0.001) per 1-Gy increase. The 5-year TLI rate increased from 0.8% for 284 lobes with Dmax <65.77 Gy to 27.1% for 176 lobes with greater doses (P<0.001). Logistic regression showed that the hazard ratio attributed to the parotid gland mean dose was 1.36 (95% CI, 1.21–1.53; P<0.001) per 1-Gy increase. Chemotherapy was not a significant factor (P=0.211).

Conclusion:

With the application of IMRT, the incidence of radiation-related complications has been reduced except for TLI. The significant factors affecting the risk of TLI included T category, chemotherapy and Dmax.

Current controversies in radiotherapy for nasopharyngeal carcinoma (NPC)

Radiotherapy has a good track record in the treatment of NPC, yet the late toxicity profile and local failure rate for locally advanced disease remain a concern. Modern RT techniques incorporating IMRT and IGRT have widened our potential in treating NPC more effectively, and shall be regarded as the standard of care. Out of the various dose fractionation regimens in IMRT, 70 Gy in 35 fractions or the mini-SIB proves to be safe in combination with chemotherapy, but any further attempt of dose escalation must be tried out with extreme caution to avoid severe toxicities. CT-MRI image fusion improves the accuracy of GTV delineation, whereas the role of PET-CT has yet to be verified. RTOG definition of the CTV provides a reasonable template for the inclusion of sites at risk of microscopic involvement, and fine tuning has to be made in the future based on careful analysis of the pattern of local failure with long term follow-up. Toxicity reduction via radiation volume or dose reduction is tempting, but once again it has to be tested under scrutiny. Retrospective data have emerged that suggest a benefit of using adaptive IMRT replanning in NPC, however the optimal timing or frequency of replanning is still unclear. Future prospective studies are thus required to evaluate the cost-effectiveness of adaptive RT and streamline the workflow logistics before it can be widely accepted in routine practice.

Fractionated stereotactic radiotherapy for 136 patients with locally residual nasopharyngeal carcinoma

Background

To evaluate the efficacy and toxicity of fractionated stereotactic radiotherapy (FSRT) in patients with residual nasopharyngeal carcinoma (NPC).

Methods

From January 2000 to December 2009, 136 NPC patients with residual lesions after primary radiotherapy (RT) were treated by FSRT. The total dose of primary RT was 68.0-78.0 Gy (median, 70.0 Gy). The median time from the primary RT to FSRT was 24.5 days. Tumor volumes for FSRT ranged from 0.60 to 77.13 cm3 (median, 13.45 cm3). The total FSRT doses were 8.0-32.0Gy (median, 19.5 Gy) with 2.0-10.0 Gy per fraction.

Results

Five-year local failure-free survival (LFFS), freedom from distant metastasis (FFDM), overall survival (OS), and disease free survival (DFS) rates for all patients were 92.5%, 77.0%, 76.2%, and 73.6%, respectively. No statistical significant differences were found in LFFS, DFS and OS in patients with stage I/II versus stage III/ IV diseases. Nineteen patients exhibited late toxicity. T stage at diagnosis was a significant prognostic factor for OS and DFS. Age was a prognostic factor for OS.

Conclusion

FSRT after external beam radiotherapy provides excellent local control for patients with residual NPC. The incidence of severe late toxicity is low and acceptable. Further investigation of optimal fractionation regimens will facilitate reduction of long-term complications.

Current management of nasopharyngeal cancer

Management of nasopharyngeal carcinoma is one of the greatest clinical challenges. Appropriate detection is not easy because of its anatomical location; sensitive biomarkers in addition to endoscopic and radiological examinations would be valuable. One useful biomarker (particularly for nonkeratinizing carcinoma) is the plasma level of Epstein-Barr viral deoxyribonucleic acid, and its role as a tool for prognostication and monitoring disease progress is presented. Radiotherapy is the primary treatment modality, and using radiation therapy in combination with chemotherapy is recommended for the treatment of locoregionally advanced tumors. Intensity-modulated radiotherapy techniques with image guidance to ensure setup precision are recommended if resources allow; adaptive replanning should be considered if major deviations from the intended dose distribution occur during the treatment course. Most contemporary series have reported encouraging results, with locoregional control exceeding 90%; the key problem is distant failure. The therapeutic margin is extremely narrow. Although significant reduction of some toxicities (eg, xerostomia) and better quality of life is now achievable especially for early stages, the risk of major late toxicities remains substantial. This review will focus on the primary treatment: the current consensus and controversies in the treatment strategy for different stages, the choice of chemotherapy regimen, and the key factors for improving the therapeutic ratio of radiotherapy will be discussed. Summary of the current achievement and direction for future improvement will be presented.

Whole-field simultaneous integrated-boost intensity-modulated radiotherapy for patients with nasopharyngeal carcinoma

PURPOSE

To retrospectively review the outcomes of our patients with newly diagnosed nondisseminated nasopharyngeal carcinoma treated with intensity-modulated radiotherapy using a whole-field simultaneous integrated-boost technique.

METHODS AND MATERIALS

A total of 175 patients treated with WF-SIB between mid-2004 and 2005 were eligible for study inclusion. The distribution of disease by stage was Stage IA in 10.9%, Stage IIA in 2.3%, Stage IIB in 21.7%, Stage III in 41.1%, Stage IVA in 14.9%, and Stage IVB in 9.1%. Of the 175 patients, 2 (1.2%), 10 (5.7%), and 163 (93.1%) had World Health Organization type I, II, and III histologic features, respectively. We prescribed 70 Gy, 60 Gy, and 54 Gy delivered in 33 fractions within 6.5 weeks at the periphery of three planning target volumes (PTV; PTV70, PTV60, and PTV54, respectively). Of the 175 patients, 46 with early T-stage disease received a brachytherapy boost, and 127 with advanced local or regional disease received chemotherapy.

RESULTS

The median follow-up period was 34 months. The overall 3-year local failure-free survival, regional failure-free survival, distant failure-free survival, and overall survival rate was 93.6%, 93.3%, 86.6%, and 87.2%, respectively. Cox regression analysis showed Stage N2-N3 disease (p = .029) and PTV (p = .024) to be independent factors predicting a greater risk of distant failure and poor overall survival, respectively. Grade 3 acute mucositis/pharyngitis occurred in 23.4% of patients, and Stage T4 disease was the only significant predictor of mucositis/pharyngitis (p = .021).

CONCLUSION

Whole-field simultaneous integrated-boost intensity-modulated radiotherapy with a dose >70 Gy achieved excellent locoregional control, without an excess incidence of severe, acute mucositis/pharyngitis, in the present study. Strategies for using such highly conformal treatment for patients with a large tumor and late N-stage disease are potential areas of investigation for future studies.

Major late toxicities after conformal radiotherapy for nasopharyngeal carcinoma-patient- and treatment-related risk factors

PURPOSE

To retrospectively analyze the factors affecting late toxicity for nasopharyngeal carcinoma.

METHODS AND MATERIALS

Between 1998 and 2003, 422 patients were treated with a conformal technique with 2-Gy daily fractions to a total dose of 70 Gy. Conventional fractionation (5 fractions weekly) was used in 232 patients and accelerated fractionation (6 fractions weekly) in 190 patients. One hundred seventy-one patients were treated with the basic radiotherapy course alone (Group 1), 55 patients had an additional boost of 5 Gy in 2 fractions (Group 2), and 196 patients underwent concurrent cisplatin-based chemotherapy (Group 3).

RESULTS

The 5-year overall toxicity rate was significantly greater in Group 3 than in Group 1 (37% vs. 27%, p = 0.009). Although the overall rate in Group 2 was not elevated (28% vs. 27%, p = 0.697), a significant increase in temporal lobe necrosis was observed (4.8% vs. 0%, p = 0.015). Multivariate analyses showed that age and concurrent chemotherapy were significant factors. The hazard ratio of overall toxicity attributed to chemotherapy was 1.99 (95% confidence interval, 1.32-2.99, p = 0.001). The mean radiation dose to the cochlea was another significant factor affecting deafness, with a hazard ratio of 1.03 (95% confidence interval, 1.01-1.05, p = 0.005) per 1-Gy increase. The cochlea that received >50 Gy had a significantly greater deaf rate (Group 1, 18% vs. 7%; and Group 3, 22% vs. 14%).

CONCLUSION

The therapeutic margin for nasopharyngeal carcinoma is extremely narrow, and a significant increase in brain necrosis could result from dose escalation. The significant factors affecting the risk of deafness included age, concurrent chemoradiotherapy, and greater radiation dose to the cochlea.

Excellent local control with stereotactic radiotherapy boost after external beam radiotherapy in patients with nasopharyngeal carcinoma

PURPOSE

To determine long-term outcomes in patients receiving stereotactic radiotherapy (SRT) as a boost after external beam radiotherapy (EBRT) for locally advanced nasopharyngeal carcinoma (NPC).

METHODS AND MATERIALS

Eight-two patients received an SRT boost after EBRT between September 1992 and July 2006. Nine patients had T1, 30 had T2, 12 had T3, and 31 had T4 tumors. Sixteen patients had Stage II, 19 had Stage III, and 47 had Stage IV disease. Patients received 66 Gy of EBRT followed by a single-fraction SRT boost of 7-15 Gy, delivered 2-6 weeks after EBRT. Seventy patients also received cisplatin-based chemotherapy delivered concurrently with and adjuvant to radiotherapy.

RESULTS

At a median follow-up of 40.7 months (range, 6.5-144.2 months) for living patients, there was only 1 local failure in a patient with a T4 tumor. At 5 years, the freedom from local relapse rate was 98%, freedom from nodal relapse 83%, freedom from distant metastasis 68%, freedom from any relapse 67%, and overall survival 69%. Late toxicity included radiation-related retinopathy in 3, carotid aneurysm in 1, and radiographic temporal lobe necrosis in 10 patients, of whom 2 patients were symptomatic with seizures. Of 10 patients with temporal lobe necrosis, 9 had T4 tumors.

CONCLUSION

Stereotactic radiotherapy boost after EBRT provides excellent local control for patients with NPC. Improved target delineation and dose homogeneity of radiation delivery for both EBRT and SRT is important to avoid long-term complications. Better systemic therapies for distant control are needed.