Salvage reirradiaton with stereotactic body radiotherapy for locally recurrent head-and-neck tumors

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.

Re-irradiation for isolated neck recurrence in head and neck tumor: impact of rN category

Unresectable, isolated lymph node recurrence after radiotherapy is rare but a candidate for re-irradiation. However, severe toxicity is anticipated. Therefore, this study aimed to explore the efficacy and toxicity of re-irradiation in isolated lymph node recurrence of head and neck lesions. We analyzed 46 patients who received re-irradiation for lymph node recurrence without local progression. The primary tumor sites included the oral cavity in 17 patients, the hypopharynx in 12, the oropharynx in seven, the larynx in three, the nasopharynx in two, and other sites. During a median follow-up time of 10 months, the median survival time was 10.6 months, and the 1-year overall survival rate was 45.5%. The 1-year local control and progression-free survival rates were 49.8% and 39.3%, respectively. According to univariate analysis, age (≥ 65 years), the interval between treatment (≥ 12 months), rN category (rN1), and gross tumor volume (GTV < 25 cm3) were predisposing factors for better survival. In the multivariate analysis, the rN category and interval were identified as statistically significant predictors. Late toxicity grade ≥ 3 occurred in four patients (8.6%). These were all Grade 5 carotid blowout syndrome, which associated with tumor invasion of the carotid artery and/ or high doses administration for the carotid artery. Small-volume rN1 tumor that recur after a longer interval is a feasible candidate for re-irradiation. However, strict patient selection and meticulous care for the carotid are required.

Stereotactic reirradiation in the treatment of head and neck cancers: A retrospective study on the long-term experience of the Oscar Lambret Center

BACKGROUND AND PURPOSE

Stereotactic radiotherapy potentially treats unresectable recurrences of previously irradiated head and neck (H&N) cancer. This study aimed to assess its efficacy and safety and evaluate prognostic factors.

MATERIALS AND METHODS

We conducted a large retrospective series that included 110 patients who had undergone 36-Gy, six-fraction stereotactic reirradiation (CyberKnife®) for recurrent/secondary H&N cancer between 2007 and 2020 at the Oscar Lambret Center. Patient characteristics and toxicities were assessed. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan-Meier method.

RESULTS

Median follow-up time was 106.3 months. The 2-year OS rate was 43.8 % (95 % confidence interval, 95 % CI, 34.3-52.9) and the median survival was 20.8 months (95 % CI, 16.5-26.3). The cumulative 2-year local-recurrence, regional-recurrence, and distant-metastasis rates were 52.2 % (95 % CI, 42.4-61.1 %), 12.8 % (95 % CI, 7.4-19.8 %), and 11 % (95 % CI, 6.0-17.6 %), respectively. 73 patients received concomitant cetuximab, and it was not significantly beneficial (HR = 1.34; 95 % CI, 0.80-2.26; p = 0.26). The cumulative incidences of grade ≥ 2 late toxicity was 42 % (CI95%: 33-51) at 24 months. Two grade 4 bleedings and no treatment-related deaths were reported.

CONCLUSION

In a large retrospective series of SBRT reirradiation for recurrent or second primary H&N cancers, we observed a median OS of 20.8 months, with a cumulative incidence of grade ≥ 2 late toxicity of 42 % at 24 months. Such a treatment is feasible. However, local recurrence rates remain non-negligible, warranting further research. Radiosensitizer use is currently under study. Therefore, establishing a balance between therapeutic modifications and toxicity is essential.

Radiation Therapy for Breast Cancer With Oligometastatic Cervical Lymph Nodes: A Case Report

Stage IV breast cancer is difficult to cure and is mainly treated with systemic therapy. However, when distant metastasis is oligometastatic, proactive treatment including local therapies for the primary lesion and distant metastases has been reported to improve prognosis. We encountered a patient who had left breast cancer with ipsilateral cervical lymph node metastases. The metastases were oligometastatic, and we treated them curatively. The patient was a female in her 50s who had been aware of a lump in the lower inner quadrant of the left breast for a few years. A biopsy was performed and left breast cancer was diagnosed pathologically. Radiological examination showed metastasis to ipsilateral axillary and cervical lymph nodes. The cervical lymph node metastases were oligometastatic, suggesting possible improvement in prognosis by multimodality treatment including local therapy. The multimodality treatment in this case comprised mastectomy with levels I and II axillary lymph node dissection, systemic therapy (including chemotherapy, endocrine therapy, and molecular targeted therapy), and postmastectomy radiation therapy. The left chest wall and left supraclavicular lymph node region were irradiated. Furthermore, following the postmastectomy radiation therapy, the cervical lymph node metastases were treated with radical radiation therapy. The cure was achieved, with recurrence-free status maintained for two years and four months after the completion of radiation therapy. This case suggests that, for breast cancer with oligometastatic involvement of cervical lymph nodes, locally treating these distant metastatic lesions with radical radiation therapy as part of multimodality treatment is beneficial.

Two novel stereotactic radiotherapy methods for locally advanced, previously irradiated head and neck cancers patients

To determine the feasibility and utility of conebeam CT-guided stereotactic radiotherapy for locally recurrent, previously irradiated head and neck cancer (HNC) patients on the Halcyon, a ring delivery system (RDS). This research aims to quantify plan quality, treatment delivery accuracy, and overall efficacy by comparing against novel clinical TrueBeam HyperArc method. Ten recurrent HNC patients who were treated at our institution on TrueBeam (6MV-FFF) for 30 to 40 Gy in 3 to 5 fractions with noncoplanar HyperArc plans were re-planned on Halcyon (6MV-FFF). These plans were re-planned with the same Acuros-based dose engine. Additionally, we used site-specific full/partial coplanar VMAT arcs. PTV coverage, mean dose to GTV, maximum dose to organs-at-risk (OAR), beam-on time (BOT), and quality assurance (QA) results were investigated and compared. Halcyon provided highly conformal HNC SRT plans with slightly superior mean PTVD99 coverage (96.7% vs 95.5%, p = 0.071), and slightly lower mean GTV dose (37.8 Gy vs 38.2 Gy, p = 0.241) when compared to the HyperArc plans. Differences in plan conformality and maximum dose to OARs were statistically insignificant. Due to Halcyon's coplanar geometry, D2cm was significantly higher (p = 0.001) but Halcyon did result in a reduced normal brain dose by 1 Gy on average and up to 5.2 Gy in some cases. Halcyon provided similar patient-specific QA pass rates with a 2%/2mm gamma criteria (98.2% vs 98.5%) and independent in-house Monte Carlo second check results (97.7% vs 98.2%), suggesting identical treatment delivery accuracy. Halcyon plans resulted in slightly longer beam-on time (3.16 vs 2.30 minutes, p = 0.010), however door-to-door patient time is expected to be <10 minutes. Compared to clinical TrueBeam HyperArc, Halcyon SRT plans provided similar plan quality and treatment delivery accuracy with a potentially faster overall treatment using fully automated patient setup and verification. Rapid delivery of recurrent HNC SRT may reduce intrafraction motion errors while also improving patient compliance and comfort. To provide high-quality of HNC SRT similar to HyperArc, we recommend Halcyon users consider commissioning this novel method. This method will be useful for remote and underserved patient cohorts including Halcyon-only clinics as well.

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.

An Overview of Head and Neck Tumor Reirradiation: What Has Been Achieved So Far?

The recurrence rate of head and neck cancers (HNCs) after initial treatment may reach 70%, and poor prognosis is reported in most cases. Curative options for recurrent HNCs mainly depend on the treatment history and the recurrent tumor localization. Reirradiation for HNCs is effective and has been included in most guidelines. However, the option remains clinically challenging due to high incidence of severe toxicity, especially in cases of quick infield recurrence. Recent technical advances in radiation therapy (RT) provide the means for upgrade in reirradiation protocols. While the majority of hospitals stay focused on conventional and widely accessible modulated RTs, the particle therapy options emerge as tolerable and providing further treatment opportunities for recurrent HNCs. Still, the progress is impeded by high heterogeneity of the data and the lack of large-scale prospective studies. This review aimed to summarize the outcomes of reirradiation for HNCs in the clinical perspective.

Stereotactic Radiotherapy in Combination with Immunotherapy in Treatment of Advanced Recurrent Squamous Cell Carcinoma of the Larynx

Squamous cell carcinoma (SCC) of the larynx in advanced stages is a challenging malignancy to treat with a high recurrence and death rate. An individualized approach to treatment is crucial in such patients. We present a 58-year-old male patient with SCC of the larynx in the T3N0M0 stage who was treated with concurrent radiochemotherapy. A total of 17 months after the radical treatment, the patient underwent a laryngectomy due to recurrence. A total of 11 months after the operation, local failure was diagnosed. In the next order, the patient received six cycles of palliative chemotherapy according to cisplatin 100 mg/m² and 5-fluorouracil 1000 mg/m². After three months, due to progression, Nivolumab-based immunotherapy was administered, ensuring disease stabilization. After the 56th cycle of Nivolumab, another progression was documented. The addition of stereotactic radiotherapy (18 Gy in three fractions) to immunotherapy led to significant regression of the disease and enabled the continuation of Nivolumab to the 70th cycle. The presented case demonstrates the usefulness of the combination of stereotactic radiotherapy with immunotherapy in prolonging the local control.

Reirradiation of head and neck squamous cell carcinomas: a pragmatic approach, part II: radiation technique and fractionations

INTRODUCTION

Reirradiation (reRT) of local recurrent/second primary tumors of the head and neck represents a potential curative treatment for patients not candidate to a salvage surgery. Aim of the present study is to summarize literature data on modern radiation techniques and fractionations used in this setting of patients.

MATERIALS AND METHODS

A narrative review of the literature was conducted on three topics: (1) target volume delineation (2) reRT dose and techniques and (3) ongoing studies. Patients treated with postoperative reRT and palliative intent were not considered for the current analysis.

RESULTS

Recommendations on the target volume contouring have been reported. 3D-Conformal Radiotherapy, Intensity Modulated Radiotherapy, Stereotactic body Radiotherapy Intraoperative Radiotherapy, Brachytherapy and Charged Particles have been analyzed in terms of indication and fractionation in the field of reRT. Ongoing studies on the topic have been reported for IMRT and Charged Particles. Moreover, according to literature data a stepwise approach has been proposed aiming to provide a useful tool to select patients candidate to a curative reRT in daily clinical practice. Two clinical cases were also provided for its application.

CONCLUSION

Different radiation techniques and fractionations can be used for a second course of radiotherapy in patients with recurrent/second primary tumor of head and neck region. Tumor characteristics as well as radiobiological considerations should be take into account to define the best reRT approach.

Safety and efficacy of CT-guided radioactive iodine-125 seed implantation as a salvage treatment for recurrent head and neck cancer after two or more courses of radiotherapy

BACKGROUND

In the past, patients with recurrent head and neck cancer (rHNC) who had previously received a high dose of radiation and were unable to undergo surgery were mainly treated with palliative chemotherapy due to the high incidence of side effects from re-irradiation. With the development of radiotherapy technology, re-irradiation of recurrent lesions by radioactive iodine-125 seed implantation (RISI) has been proposed as a feasible therapeutic approach. This study aimed to investigate the safety and efficacy of computed tomography (CT)-guided RISI in the treatment of rHNC after two or more courses of radiotherapy, and to analyze the prognostic factors.

METHODS

Data of 33 patients with rHNC who received CT-guided RISI after two or more courses of radiotherapy were collected and statistically analyzed. The median cumulative dose of the previous radiotherapy was 110 Gy. Short-term efficacy was assessed by Response Evaluation Criteria in Solid Tumors (version 1.1) criteria, while adverse events were evaluated by Common Terminology Criteria for Adverse Events (version 5.0) criteria.

RESULTS

The median gross tumor volume (GTV) was 29.5 cc, and the postoperative median dose to 90% of target volume (D90) was 136.8 Gy. For adverse reactions, enhanced pain was found in 3 (9.1%) patients, followed by grade 1 to 2 acute skin reactions in 3 (9.1%) patients, grade 2 to 3 late skin reactions in 2 (6.1%) patients, grade 1 to 2 early mucosal reactions in 4 (12.1%) patients, and mandibular osteonecrosis in 1 (3.0%) patient. Regarding the treatment efficacy, the 1- and 2-year local control (LC) rates were 47.8% and 36.4% (median LC time, 10 months), and the 1- and 2-year overall survival (OS) rates were 41.3% and 32.2% (median OS time, 8 months). The absence of adverse events was associated with better LC.

CONCLUSIONS

CT-guided RISI, as a salvage therapy, demonstrated acceptable safety and efficacy in the treatment of rHNC after two or more courses of radiotherapy.

TRIAL REGISTRATION

This study was registered at Chinese Clinical Trial Register database (Registration No. ChiCTR2200063261 ) in September 2, 2022.

A Treatment Approach for Carotid Blowout Syndrome and Soft Tissue Reconstruction after Radiotherapy in Patients with Oral Cancer: A Report of 2 Cases

BACKGROUND

This retrospective case series study aims to demonstrate a salvage technique for the treatment of carotid blow-out syndrome (CBS) in irradiated head and neck cancer patients with a vessel-depleted neck.

METHODS

Between October 2017 and October 2021, two patients (N = 2) with CBS were treated at our institution in a multidisciplinary approach together with the Department of Vascular Surgery. Patients were characterized based on diagnoses, treatment procedures, and the subsequent postoperative course.

RESULTS

Surgical emergency intervention was performed in both cases. The transition zone from the common carotid artery (CCA) to the internal carotid artery (ICA) was resected and reconstructed with a xenogic (case 1) or autogenic (case 2) interposition (end-to-end anastomosis). To allow reconstruction of the vascular defect, an additional autologous vein graft was anastomosed to the interposition graft in an end-to-side technique, allowing arterial anastomosis for a free microvascular flap without re-clamping of the ICA. Because of the intraoperative ICA reconstruction, none of the patients suffered a neurological deficit.

CONCLUSIONS

The techniques presented in the form of two case reports allow for acute bleeding control, cerebral perfusion, and the creation of a vascular anastomosis option in the vessel-depleted neck.

Reirradiation for local recurrence of oral, pharyngeal, and laryngeal cancers: a multi-institutional study

This study aimed to examine the efficacy and toxicity of reirradiation in patients with locally recurrent oral, pharyngeal, and laryngeal cancers. We conducted a retrospective, multi-institutional analysis of 129 patients with previously irradiated cancer. The most frequent primary sites were the nasopharynx (43.4%), oral cavity (24.8%), and oropharynx (18.6%). With a median follow-up duration of 10.6 months, the median overall survival was 14.4 months and the 2-year overall survival rate was 40.6%. For each primary site, the 2-year overall survival rates were 32.1%, 34.6%, 30%, 60.8%, and 5.7% for the hypopharynx, oral cavity, larynx, nasopharynx, and oropharynx, respectively. Prognostic factors for overall survival were primary site (nasopharynx versus other sites) and gross tumor volume (GTV) (≤ 25 cm³ versus > 25 cm³). The 2-year local control rate was 41.2%. Twenty-four patients (18.6%) presented with grade ≥ 3 toxicities, including nine with hemorrhages that led to grade 5 toxicities in seven patients. All nine tumors that caused hemorrhage showed tumor encasement of the carotid ≥ 180 degrees and eight of nine tumors had larger GTV > 25 cm³. Reirradiation is a feasible treatment option for small local recurrence of oral, pharyngeal, and laryngeal cancers, with the requirement of a strict eligibility assessment for large tumors with carotid encasement.

Radiotherapy, Chemotherapy and Immunotherapy-Current Practice and Future Perspectives for Recurrent/Metastatic Oral Cavity Squamous Cell Carcinoma

Oral squamous cell carcinoma is the most common malignant epithelial neoplasm affecting the oral cavity. While surgical resection is the cornerstone of a multimodal curative approach, some tumors are deemed recurrent or metastatic (R/M) and often not suitable for curative surgery. This mainly occurs due to the extent of lesions or when surgery is expected to result in poor functional outcomes. Amongst the main non-surgical therapeutic options for oral squamous cell carcinoma are radiotherapy, chemotherapy, molecular targeted agents, and immunotherapy. Depending on the disease setting, these therapeutic approaches can be used isolated or in combination, with distinct efficacy and side effects. All these factors must be considered for treatment decisions within a multidisciplinary approach. The present article reviews the evidence regarding the treatment of patients with R/M oral squamous cell carcinoma. The main goal is to provide an overview of available treatment options and address future therapeutic perspectives.

Current radiotherapy for recurrent head and neck cancer in the modern era: a state-of-the-art review

BACKGROUND

In the management of head and neck cancer (HNC) patients, local recurrence is a common cause of treatment failure. Only a few patients with recurrent HNC (rHNC) are eligible for salvage surgery and the majority of patients receive systemic therapy and radiotherapy. In recent years, with the development of irradiation technology, radiotherapy for rHNC patients has markedly attracted clinicians' attention and its therapeutic effects on patients with end-stage cancer are worthy of investigation as well.

METHODS

Several studies have investigated the role of radiotherapy in the treatment of rHNC patients. We reviewed retrospective reports and prospective trials published in recent decades that concentrated on the management of rHNC.

RESULTS

A growing body of evidence supported the application of irradiation to rHNC patients. According to the results of this review, current radiotherapy could achieve a better efficacy with a lower incidence of toxicity.

CONCLUSION

Radiotherapy is a promising treatment for rHNC patients.

Salvage Post-Operative Stereotatic Ablative Radiotherapy for Re-Current Squamous Cell Carcinoma of Head and Neck

Background and Objectives: Patients with recurrent squamous cell carcinoma of the head and neck (rHNC) face an aggressive disease. Surgical resection is the gold standard treatment. Immediate adjuvant post-operative stereotactic ablative radiotherapy (PO-SABR) for rHNC is debatable. Materials and Methods: We retrospectively identified patients who were treated with PO-SABR at the AC Camargo Cancer Center, Brazil. Results: Eleven patients were treated between 2018 and 2021. The median time between salvage surgery and PO-SABR was 31 days (range, 25–42) and the median PO-SABR total dose was 40 Gy (range, 30–48 Gy). The 2-and 4-year actuarial DFS were 62.3% and 41.6%, while the 2-and 4-year OS probabilities were 80.0% and 53.3%, respectively. Eight (72.7%) patients were alive and six (54.5%) were without disease at the last follow-up. Two (18.1%) patients had local failure in the PO-SABR field. Three (27.3%) patients had distant metastasis, diagnosed in a median time of 9 months (range, 4–13) after completion of PO-SABR. On univariate analysis, predictive factors related to worse OS were: interval between previous radiotherapy and PO-SABR ≤ 24 months (p = 0.033) and location of the salvage target in the oral cavity (p = 0.013). The total dose of PO-SABR given in more than three fractions was marginally statistically significant, favoring the OS (p = 0.051). Conclusions: Our results encourage the use of a more aggressive approach in selected patients with rHNC by combining salvage surgery with immediate PO-SABRT, but this association needs to be further explored.

Feasibility of drug-eluting embolics chemoembolization for the management of recurrent/advanced head and neck cancer

PURPOSE

To characterize the safety, tolerability, and efficacy of chemoembolization with drug-eluting embolic (DEE) microspheres in patients with recurrent and advanced head and neck cancer.

MATERIALS AND METHODS

In this retrospective study, 32 patients (mean age, 57.2 ± 2.8 years; 17 women) with recurrent (n=16) and advanced (n=16) head and neck cancer were treated with chemoembolization with DEE microspheres loaded with doxorubicin. Treatment response, overall survival, local progression-free survival, and adverse events were evaluated.

RESULTS

At six months after the procedure, the objective response and disease control rates were 25% and 69%, respectively. The median overall survival and local progression-free survival were 14.5 and 13.6 months, respectively. Seven patients (22%) experienced adverse events after the chemoembolization procedure. All adverse events were related to post-embolization syndrome, including vomiting and nausea (n=1), pyrexia (n=2) and localized pain (n=7). No severe adverse events or procedure-related deaths were observed.

CONCLUSION

Chemoembolization with DEE microspheres was safe and tolerable in patients with recurrent and advanced head and neck cancer.

Retreatment of Recurrent or Second Primary Head and Neck Cancer After Prior Radiation: Executive Summary of the American Radium Society® (ARS) Appropriate Use Criteria (AUC): Expert Panel on Radiation Oncology - Head and Neck Cancer

BACKGROUND

Re-treatment of recurrent or second primary head and neck cancers occurring in a previously irradiated field is complex. Few guidelines exist to support practice.

METHODS

We performed an updated literature search of peer-reviewed journals in a systematic fashion. Search terms, key questions, and associated clinical case variants were formed by panel consensus. The literature search informed the committee during a blinded vote on the appropriateness of treatment options via the modified Delphi method.

RESULTS

The final number of citations retained for review was 274. These informed five key questions, which focused on patient selection, adjuvant re-irradiation, definitive re-irradiation, stereotactic body radiation (SBRT), and re-irradiation to treat non-squamous cancer. Results of the consensus voting are presented along with discussion of the most current evidence.

CONCLUSIONS

This provides updated evidence-based recommendations and guidelines for the re-treatment of recurrent or second primary cancer of the head and neck.

HyperArc VMAT stereotactic radiotherapy for locally recurrent previously‐irradiated head and neck cancers: Plan quality, treatment delivery accuracy, and efficiency

Purpose

Materials/Methods

Results

Conclusion

Stereotactic body radiotherapy optimization to reduce the risk of carotid blowout syndrome using normal tissue complication probability objectives

Purpose

To determine the possibility of further improving clinical stereotactic body radiotherapy (SBRT) plans using normal tissue complication probability (NTCP) objectives in order to minimize the risk for carotid blowout syndrome (CBOS).

Methods

10 patients with inoperable locally recurrent head and neck cancer, who underwent SBRT using CyberKnife were analyzed. For each patient, three treatment plans were examined: (1) cone‐based without delineation of the ipsilateral internal carotid (clinical plan used to treat the patients); (2) cone‐based with the carotid retrospectively delineated and spared; and (3) Iris‐based with carotid sparing. The dose–volume histograms of the target and primary organs at risk were calculated. The three sets of plans were compared based on dosimetric and TCP/NTCP (tumor control and normal tissue complication probabilities) metrics. For the NTCP values of carotid, the relative seriality model was used with the following parameters: D₅₀ = 40 Gy, γ = 0.75, and s = 1.0.

Results

Across the 10 patient plans, the average TCP did not significantly change when the plans were re‐optimized to spare the carotid. The estimated risk of CBOS was significantly decreased in the re‐optimized plans, by 14.9% ± 7.4% for the cone‐based plans and 17.7% ± 7.1% for the iris‐based plans (p = 0.002 for both). The iris‐based plans had significant (p = 0.02) reduced CBOS risk and delivery time (20.1% ± 7.4% time reduction, p = 0.002) compared to the cone‐based plans.

Conclusion

A significant improvement in the quality of the clinical plans could be achieved through the delineation of the internal carotids and the use of more modern treatment delivery modalities. In this way, for the same target coverage, a significant reduction in the risk of CBOS could be achieved. The range of risk reduction varied depending on the proximity of carotid artery to the target.

Stereotactic body ablative radiotherapy for reirradiation of small volume head and neck cancers is associated with prolonged survival: Large, single-institution, modern cohort study

BACKGROUND

Recurrent head and neck cancer has poor prognosis. Stereotactic body radiotherapy (SBRT) may improve outcomes by delivering ablative radiation doses.

METHODS

We reviewed patients who received definitive-intent SBRT reirradiation at our institution from 2013 to 2020. Patterns of failure, overall survival (OS), and toxicities were analyzed.

RESULTS

One hundred and thirty-seven patients were evaluated. The median OS was 44.3 months. The median SBRT dose was 45 Gy and median target volume 16.9 cc. The 1-year local, regional, and distant control was 78%, 66%, and 83%, respectively. Systemic therapy improved regional (p = 0.004) and distant control (p = 0.04) in nonmetastatic patients. Grade 3+ toxicities were more common at mucosal sites (p = 0.001) and with concurrent systemic therapy (p = 0.02).

CONCLUSIONS

In a large cohort of SBRT reirradiation for recurrent, small volume head and neck cancers, a median OS of 44.3 months was observed. Systemic therapy improved regional and distant control. Toxicities were modulated by anatomic site and systemic therapy.

Proton re-irradiation of unresectable recurrent head and neck cancers

Background

This study presents a retrospective analysis (efficacy and toxicity) of outcomes in patients with unresectable recurrence of previously irradiated head and neck (H&N) cancers treated with proton therapy. Locoregional recurrence is the main pattern of failure in the treatment of H&N cancers. Proton re-irradiation in patients with relapse after prior radiotherapy might be valid as promising as a challenging treatment option.

Materials and methods

From November 2015 to January 2020, 30 patients with in-field recurrence of head and neck cancer, who were not suitable for surgery due to medical contraindications, tumor localization, or extent, received re-irradiation with intensity-modulated proton therapy (IMPT). Sites of retreatment included the aerodigestive tract (60%) and the base of skull (40%). The median total dose of prior radiotherapy was 55.0 Gy. The median time to the second course was 38 months. The median re-irradiated tumor volume was 158.1 cm³. Patients were treated with 2.0, 2.4, and 3.0 GyRBE per fraction, with a median equivalent dose (EQD₂) of 57.6 Gy (α/β = 10). Radiation-induced toxicity was recorded according to the RTOG/EORTC criteria.

Results

The 1- and 2-year local control (LC), progression-free survival (PFS), and overall survival (OS) were 52.6/21.0, 21.9/10.9, and 73.4/8.4%, respectively, with a median follow-up time of 21 months. The median overall survival was 16 months. Acute grade 3 toxicity was observed in one patient (3.3%). There were five late severe side effects (16.6%), with one death associated with re-irradiation.

Conclusion

Re-irradiation with a proton beam can be considered a safe and efficient treatment even for a group of patients with unresectable recurrent H&N cancers.

Risk factors and nomogram for predicting carotid blowout syndrome based on computed tomography angiography

OBJECTIVES

To identify independent factors for head and neck cancer (HNC) patients with carotid blowout syndrome (CBS) and construct a nomogram to predict risk of CBS preoperatively based on computed tomography angiography (CTA) imaging.

SUBJECT AND METHODS

From January 2010 to July 2020, 73 HNC patients who had surgery in hospitalization and underwent CTA examination for head and neck region were included in this study. Vascular alterations and the relationship between carotid artery (CA) and tumor were evaluated in CTA. Clinical and CTA imaging features were distinguished by logistic regression analysis and used to perform receiver operating curve analysis. Nomogram was created to predict risk of CBS and assessed by concordance index (C-index) and calibration curve.

RESULTS

Three independent risk factors were identified, including radical neck dissection, CA surrounded by tumor, and CA invaded by tumor without clear boundary. Area under curve of the combination of 3 variables was 0.836 (95% CI, 0.72-0.952, p < 0.001). The C-index of nomogram was 0.84 (95% CI, 0.73-0.94), and the calibration plot showed a good fitting between prediction and observation.

CONCLUSIONS

We established a useful nomogram based on CTA imaging, which showed a satisfied efficacy for evaluating risk of CBS in HNC patients preoperatively.

Initial Data Pooling for Radiation Dose-Volume Tolerance for Carotid Artery Blowout and Other Bleeding Events in Hypofractionated Head and Neck Retreatments

PURPOSE

Dose-volume data for injury to carotid artery and other major vessels in stereotactic body radiation therapy (SBRT)/SABR head and neck reirradiation were reviewed, modeled, and summarized.

METHODS AND MATERIALS

A PubMed search of the English-language literature (stereotactic and carotid and radiation) in April 2018 found 238 major vessel maximum point doses in 6 articles that were pooled for logistic modeling. Two subsequent studies with dose-volume major vessel data were modeled separately for comparison. Attempts were made to separate carotid blowout syndrome from other bleeding events (BE) in the analysis, but we acknowledge that all except 1 data set has some element of BE interspersed.

RESULTS

Prior radiation therapy (RT) dose was not uniformly reported per patient in the studies included, but a course on the order of conventionally fractionated 70 Gy was considered for the purposes of the analysis (with an approximately ≥6-month estimated interval between prior and subsequent treatment in most cases). Factors likely associated with reduced risk of BE include nonconsecutive daily treatment, lower extent of circumferential tumor involvement around the vessel, and no surgical manipulation before or after SBRT.

CONCLUSIONS

Initial data pooling for reirradiation involving the carotid artery resulted in 3 preliminary models compared in this Hypofractionated Treatment Effects in the Clinic (HyTEC) report. More recent experiences with alternating fractionation schedules and additional risk-reduction strategies are also presented. Complications data for the most critical structures such as spinal cord and carotid artery are so limited that they cannot be viewed as strong conclusions of probability of risk, but rather, as a general guideline for consideration. There is a great need for better reporting standards as noted in the High Dose per Fraction, Hypofractionated Treatment Effects in the Clinic introductory paper.

A systematic review and practical considerations of stereotactic body radiotherapy in the treatment of head and neck cancer

OBJECTIVES

Stereotactic radiotherapy (SBRT) is gaining popularity although its use in head and neck cancer (HNC) is not well defined. The primary objective was to review the published evidence regarding the use of stereotactic radiotherapy in HNC.

METHODS

A literature search was performed by using MEDLINE and EMBASE databases for eligible studies from 2000 to 2019 and 26 relevant studies were identified.

RESULTS

Literature demonstrates a heterogeneous use of this technique with regards to patient population, primary or salvage treatment, dose fractionation regimens, outcomes and follow-up protocols. Carotid blow out syndrome is a risk as with other forms of reirradiation but alternative treatment regimens may reduce this risk.

CONCLUSION

At present there is a lack of evidence regarding SBRT as a primary treatment option for HNC and definitive answers regarding efficacy and tolerability cannot be provided but there is growing evidence that SBRT reirradiation regimens are safe and effective. In lieu of evidence from large Phase III trials, we define appropriate organ at risk constraints and prescription doses, with accurate plan summation approaches. Prospective randomised trials are warranted to validate improved treatment outcomes and acceptable treatment morbidity.

ADVANCES IN KNOWLEDGE

This article provides a comprehensive review of evidence of use of stereotactic radiotherapy in HNC site (either as a primary treatment or as reirradiation). We also provide an evidence-based approach to the implementation and practical consideration of stereotactic radiotherapy in HNC.

Radical external beam re-irradiation in the treatment of recurrent head and neck cancer: Critical review

Management of patients with recurrent head and neck cancer remains a challenge for the surgeon as well as the treating radiation oncologist. Even in the era of modern radiotherapy, the rate of severe toxicity remains high with unsatisfactory treatment results. Intensity-modulated radiation therapy (IMRT), stereotactic body radiation therapy (SBRT), and heavy-ion irradiation have all emerged as highly conformal and precise techniques that offer many radiobiological advantages in various clinical situations. Although re-irradiation is now widespread in clinical practice, little is known about the differences in treatment response and toxicity using diverse re-irradiation techniques. In this review, we provide a comprehensive overview of the role of radiation therapy in recurrent or second primary head and neck cancer including patient selection, therapeutic outcome, and risk using different re-irradiation techniques. Critical review of published evidence on IMRT, SBRT, and heavy-ion full-dose re-irradiation is presented including data on locoregional control, overall survival, and toxicity.

Carotid blowout syndrome after reirradiation for head and neck malignancies: a comprehensive systematic review for a pragmatic multidisciplinary approach

AIM

To provide a literature review on risk factors and strategies to prevent acute carotid blowout (CBO) syndrome in patients who underwent reirradiation (reRT) for recurrent head and neck (HN) malignancies.

PATIENTS AND METHODS

Inclusion criteria were: 1) CBO following reRT in the HN region, 2) description on patient-, tumor- or treatment-related risk factors, 3) clinical or radiological signs of threatened or impending CBO, and 4) CBO prevention strategies.

RESULTS

Thirty-five studies were selected for the analysis from five hundred seventy-seven records. Results provided indications on clinical, radiological and dosimetric parameters possibly associated with higher risk of CBO. Endovascular procedures (artery occlusion and stenting) to prevent acute massive hemorrhage in high risk patients were discussed.

CONCLUSION

Literature data are still scarce with a low level of evidence. Nevertheless, the present work provides a comprehensive review useful for clinicians as a multidisciplinary pragmatic tool in their clinical practice.

Conventionally fractionated large volume head and neck re-irradiation using multileaf collimator-based robotic technique: A feasibility study

Purpose

To report on the feasibility and performance of conventionally fractionated multileaf collimator (MLC)-based robotic stereotactic body re-irradiation of the head and neck region using MLC-based Cyberknife (CK) technology.

Methods

Patients treated for recurrent or second primary head and neck cancer (HNC) with curative proton therapy to a target volume > 30 cm³ between 2011 and 2015 were included. MLC-based CK plans were generated using the CK M6 InCise2 MLC system. Dose statistics from MLC-based CK plans were compared to proton beam therapy (PBT) plans according to the following metrics: target coverage, target homogeneity index, gradient index, Paddick conformity index (CI), prescription isodose volume (PIV), treatment time (tTime) for one fraction as well as doses to organs at risk (OAR). Wilcoxon signed-rank test was used to compare dose metrics.

Results

Eight patients were included; the tumor sites included: salivary glands, pharynx (oropharynx, hypopharynx and retropharynx) and sinonasal cavities. Five of 8 patients were treated with multifield optimisation intensity modulated proton therapy, 3 were treated with passive scattering proton therapy. Median dose was 67 Gy (range 60-70) in 32 fractions (range 30-35). The median high-dose planning target volume (PTV) was 45.4 cm³ (range 2.4 - 130.2 cm³) and the median elective PTV was 91.9 cm³ (range 61.2 - 269.7 cm³). Overall, the mean target coverage (mean 98.3% vs. 96.2% for CK vs. PBT, respectively), maximum dose to PTV (mean 111% vs. 111%, p = 0.2) and mean dose to PTV (mean 104% vs. 104%) were similar across modalities. Highly conformal plans were achieved with both modalities, but mean CI was better with PBT (0.5 vs. 0.6 for CK vs. PBT, p = 0.04). Homogeneity and gradient indexes were similar between the 2 modalities; mean tTime with PBT and CK was 17 vs. 18 min, respectively (p = 0.7). Case-based study revealed that CK and PBT plans allowed for excellent sparing of OAR, with some clinical scenarios associated with better performance of CK while others with better performance of PBT.

Conclusion

Our study has demonstrated the dosimetric performance of large volume head and neck re-irradiation using MLC-based CK in various clinical scenarios. While conformity was generally better achieved with PBT, MLC-based CK allowed for high dose gradient leading to rapid dose drop-off and sparing of OAR. Conventionally fractionated MLC-based CK could be a competitive alternative in large volume head and neck re-irradiation that deserves further investigation in the clinical setting.

Estimating PTV Margins in Head and Neck Stereotactic Ablative Radiation Therapy (SABR) Through Target Site Analysis of Positioning and Intrafractional Accuracy

PURPOSE

Recurrent or previously irradiated head and neck cancers (HNC) are therapeutically challenging and may benefit from high-dose, highly accurate radiation techniques, such as stereotactic ablative radiation therapy (SABR). Here, we compare set-up and positioning accuracy across HNC subsites to further optimize the treatment process and planning target volume (PTV) margin recommendations for head and neck SABR.

METHODS AND MATERIALS

We prospectively collected data on 405 treatment fractions across 79 patients treated with SABR for recurrent/previously irradiated HNC. First, interfractional error was determined by comparing ExacTrac x-ray to the treatment plan. Patients were then shifted and residual error was measured with repeat x-ray. Next, cone beam computed tomography (CBCT) was compared with ExacTrac for positioning agreement, and final shifts were applied. Lastly, intrafractional error was measured with x-ray before each arc. Results were stratified by treatment site into skull base, neck/parotid, and mucosal.

RESULTS

Most patients (66.7%) were treated to 45 Gy in 5 fractions (range, 21-47.5 Gy in 3-5 fractions). The initial mean ± standard deviation interfractional errors were -0.2 ± 1.4 mm (anteroposterior), 0.2 ± 1.8 mm (craniocaudal), and -0.1 ± 1.7 mm (left-right). Interfractional 3-dimensional vector error was 2.48 ± 1.44, with skull base significantly lower than other sites (2.22 vs 2.77; P = .0016). All interfractional errors were corrected to within 1.3 mm and 1.8°. CBCT agreed with ExacTrac to within 3.6 mm and 3.4°. CBCT disagreements and intrafractional errors of >1 mm or >1° occurred at significantly lower rates in skull base sites (CBCT: 16.4% vs 50.0% neck, 52.0% mucosal, P < .0001; intrafractional: 22.0% vs 48.7% all others, P < .0001). Final PTVs were 1.5 mm (skull base), 2.0 mm (neck/parotid), and 1.8 mm (mucosal).

CONCLUSIONS

Head and neck SABR PTV margins should be optimized by target site. PTV margins of 1.5 to 2 mm may be sufficient in the skull base, whereas 2 to 2.5 mm may be necessary for neck and mucosal targets. When using ExacTrac, skull base sites show significantly fewer uncertainties throughout the treatment process, but neck/mucosal targets may require the addition of CBCT to account for positioning errors and internal organ motion.

Contact lens-type ocular in vivo dosimeter for radiotherapy

PURPOSE

This study aimed to (a) develop a contact lens-type ocular in vivo dosimeter (CLOD) that can be worn directly on the eye and (b) assess its dosimetric characteristics and biological stability for radiation therapy.

METHODS

The molder of a soft contact lens was directly used to create the dosimeter, which included a radiation-sensitive component - an active layer similar to a radiochromic film - to measure the delivered dose. A flatbed scanner with a reflection mode was used to measure the change in optical density due to irradiation. The sensitivity, energy, dose rate, and angular dependence were tested, and the uncertainty in determining the dose was calculated using error propagation analysis. Sequential biological stability tests, specifically, cytotoxicity and ocular irritation tests, were conducted to ensure the safe application of the CLOD to patients.

RESULTS

The dosimeter demonstrated high sensitivity in the low dose region, and the sensitivity linearly decreased with the dose. The responses obtained for the 10 and 15 MV photon beams were 1.7% and 1.9% higher compared to the 6 MV photon beam. A strong dose rate dependence was not obtained for the CLOD. Angular dependence was observed from 90° to 180° with a difference in response from 1% to 2%. The total uncertainty in error propagation analysis decreased as a function of the dose in the red channel. For a dose range of 0 to 50 cGy, the total uncertainties for 5, 10, and 50 cGy were 14.2%, 8.9%, and 5%, respectively. Quantitative evaluation using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) method presented no cytotoxicity. Further, no corneal opacity, iris reaction, or conjunctival inflammation was observed.

CONCLUSIONS

The CLOD is the first dosimeter that can be worn close to the eye. The results of cytotoxicity and irritation tests indicate that it is a stable medical device. The evaluation of dose characteristics in open field conditions shows that the CLOD can be applied to an in vivo dosimeter in radiotherapy.

Efficacy and Feasibility of Salvage Re-Irradiation with CyberKnife for In-Field Neck Lymph Node Recurrence: A Retrospective Study

Neck lymph node (LN) recurrence in the irradiated field represents an important aspect of treatment failure after primary radiotherapy owing to the lack of a standard treatment. The aim of this study is to investigate the efficacy and safety of CyberKnife treatment for neck LN recurrence after radiotherapy. Between 2008 and 2016, 55 neck LN recurrences after radiotherapy in 16 patients were treated with CyberKnife. The median follow-up period was 17 months (range, 2–53 months). The median previous radiotherapy dose was 68 Gy (range, 50–70 Gy). The median marginal dose as equivalent dose delivered in 2-Gy fractions (α/β = 10) was 50 Gy (range, 40–58 Gy). The one-year local control (LC) and overall survival rates were 81% and 71%, respectively. The one-year LC was higher with a target volume ≤1.0 cm³ than that with a target volume >1.0 cm³ (p = 0.006). Fatal bleeding was observed in one patient who had large (91 cm³) and widespread tumor with invasion to the carotid artery before CyberKnife treatment. CyberKnife treatment for neck LN recurrence is safe and feasible in most cases. Indication for the treatment should be carefully considered for large and widespread tumors.

Quality of Life Outcomes Following Organ-Sparing SBRT in Previously Irradiated Recurrent Head and Neck Cancer

Purpose: To present a retrospective analysis of the efficacy, toxicity, and quality of life (QoL) of patients treated with OAR _Extreme -sparing stereotactic body radiotherapy (SBRT) in previously-irradiated head and neck cancer. Materials/Methods: From 11/2012 to 7/2015, 60 patients with in-field recurrence of head and neck cancer underwent re-irradiation with SBRT. Retreatment sites included the aerodigestive tract (43%), lateral neck (22%), and skull base (35%). The median prior RT dose was 63.6 Gy with a median time from prior irradiation of 16.5 months. The median volume treated was 61.0 cc. Patients were treated with 40 Gy in the definitive setting or 35 Gy in the post-operative setting in five fractions. Dose constraints to the OAR _Extreme were calculated with a BED calculator using an alpha/beta ratio of 3 to reduce the risk of late toxicities. QoL data was collected from patients at the time of consultation and at subsequent follow up appointments using the MD Anderson Dysphagia Inventory (MDADI) and Symptom Inventory (MDASI). Results: The 1- and 2- year rates of local, regional, and distant control and overall survival were 79/79, 74/70, 74/71, and 59/45%, respectively. Late grade 3 toxicities were seen in 3% in the group treated to the aerodigestive tract and 1% in the group treated to the skull base. No grade 4 or 5 toxicities were observed. Patients with skull base re-irradiation maintained a stable QoL score after radiation treatment, while patients treated to the aerodigestive tract demonstrated a slight impairment associated with worsening dysphagia, compared to their pretreatment baseline. All groups experienced an increase in xerostomia. Conclusions: OAR _Extreme -sparing SBRT is able to achieve excellent tumor coverage while protecting the organs at highest risk of re-irradiation-related complications. The potential for lower toxicities and maintained QoL with this treatment makes it a promising option for salvage of recurrent head and neck cancer.

Summary

Local control and overall survival rates for recurrent head and neck cancer remain poor, despite the use of local therapy. In addition, re-irradiation with conventional radiation therapy confers a high rate of grade 3 and higher late toxicities. SBRT appears to improve the therapeutic ratio in this patient population, and treatment planning with a focus on sparing OAR _Extreme may further decrease the rates of morbidity in these patients.

Long-term outcomes following stereotactic body radiotherapy boost for oropharyngeal squamous cell carcinoma

Background/purpose: To determine the efficacy and toxicity profile of a stereotactic body radiotherapy (SBRT) boost as a first line treatment in patients with oropharyngeal squamous cell carcinoma (OPSCC). Materials and methods: We performed a retrospective cohort study in 195 consecutive OPSCC patients with T1-small T3 disease, treated at Erasmus MC between 2009 and 2016 with a SBRT (3 × 5.5 Gy) boost after 46 Gy IMRT. Primary endpoints were disease-specific survival (DSS) and Grade ≥3 toxicity (Common Terminology Criteria). The Kaplan-Meier method and Cox regression model were applied to determine rates and risk factors. Results: The median follow-up was 4.3 years. Treatment compliance was high (100%). Rates of 5-year DSS and late grade ≥3 toxicity were 85% and 28%, respectively. Five-year overall survival was 67%. The most frequently observed toxicities were mucosal ulceration or soft tissue necrosis (n = 30, 5 year 18%), dysphagia or weight loss (n = 18, 5 year 12%) and osteoradionecrosis (n = 11, 5 year 9%). Current smoker status (hazard ratio [HR] = 2.9, p = .001) and Charlson Comorbidity Index ≥2 (HR = 1.9, p = .03) were was associated with increased toxicity risk. Tooth extraction prior to RT was associated with increased osteoradionecrosis risk (HR = 6.4, p = .006). Conclusion: We reported on outcomes in the largest patient series to date treated with a hypofractionated boost for OPSCC. Efficacy was good with survival rates comparable to conventionally fractionated (chemo)radiotherapy. Grade ≥3 toxicity profiles showed high rates of soft tissue necrosis and osteoradionecrosis. Strategies to mitigate severe toxicity risks are under investigation to improve the tolerability of the SBRT boost.

Second infield re-irradiation with a resulting cumulative equivalent dose (EQD2max ) of >180 Gy for patients with recurrent head and neck cancer

BACKGROUND

For locally recurrent head and neck cancer, re-irradiation with modern techniques like stereotactic body radiotherapy is a promising, possibly curative alternative to palliative systemic therapy.

METHODS

We report on 1 patient with nasopharyngeal carcinoma (NPC) and 1 patient with cutaneous squamous cell carcinoma (SCC). Both patients received full dose primary treatment (>66 Gy, EQD2), full dose re-irradiation (>50 Gy, EQD2), and a second course of re-irradiation via robotic radiosurgery (CyberKnife) for a second local recurrence.

RESULTS

Both treatments resulted in adequate tumor response. No grade III-IV acute or late toxicities occurred. Follow-up at 6 months after third irradiation showed partial remission for the patient with NPC. In the second case (SCC), no toxicities occurred and the tumor was in remission 18 months after last treatment.

CONCLUSION

These cases show that a second course of re-irradiation utilizing modern techniques like robotic radiosurgery might be feasible for carefully selected patients with head and neck cancer.

Carotid blowout syndrome: modern trends in management

Carotid blowout syndrome (CBS) refers to rupture of the carotid artery and is an uncommon complication of head and neck cancer that can be rapidly fatal without prompt diagnosis and intervention. CBS develops when a damaged arterial wall cannot sustain its integrity against the patient’s blood pressure, mainly in patients who have undergone surgical procedures and radiotherapy due to cancer of the head and neck, or have been reirradiated for a recurrent or second primary tumor in the neck. Among patients irradiated prior to surgery, CBS is usually a result of wound breakdown, pharyngocutaneous fistula and infection. This complication has often been fatal in the past, but at the present time, early diagnosis and modern technology applied to its management have decreased morbidity and mortality rates. In addition to analysis of the causes and consequences of CBS, the purpose of this paper is to critically review methods for early diagnosis of this complication and establish individualized treatment based on endovascular procedures for each patient.

Salvage Stereotactic Body Radiation Therapy for Locally Recurrent Previously Irradiated Head and Neck Squamous Cell Carcinoma: An Analysis from the RSSearch® Registry

Objectives

To report on overall survival (OS), local control (LC), dose-outcome relationships, and related toxicities following stereotactic body radiation therapy (SBRT) for locally recurrent, previously irradiated squamous cell carcinoma of the head and neck (rSCCHN).

Methods

We queried the prospectively-maintained RSSearch® Registry for patients with rSCCHN treated with five-fraction SBRT from January 2008 to November 2016. Patients with non-squamous cell histology, missing registry data regarding prior irradiation, those treated with less than five fractions of SBRT, and those treated with SBRT in primary or boost settings were excluded. LC and OS were estimated using the Kaplan-Meier method with comparisons between groups completed using log-rank t-tests and multivariable Cox regression. Logistic regression analyses were used to examine factors predictive of toxicity.

Results

Forty-five rSCCHN patients treated with SBRT delivered in five fractions at 12 radiotherapy centers were identified. Prescription doses ≥ 40 Gy were associated with higher one-year rates of OS, LC, and a higher likelihood of experiencing toxicities. Acute and late toxicity rates were low (22.2% and 15.6%, respectively) and were all Grade 1-2 with only one late Grade 3 esophagitis.

Conclusion

Salvage SBRT for rSCCHN resulted in outcomes comparable to prior single-institutional reports in a multi-institutional cohort across clinical settings with low toxicity, thus supporting more widespread adoption of SBRT with recommended doses ≥ 40 Gy.

[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.

Deep hyperthermia with the HYPERcollar system combined with irradiation for advanced head and neck carcinoma - a feasibility study

PURPOSE

Radiotherapy (RT) treatment of locally-advanced and recurrent head and neck carcinoma (HNC) results in disappointing outcomes. Combination of RT with cisplatin or cetuximab improves survival but the increased toxicity and patient's comorbidity warrant the need for a less-toxic radiosensitizer. Stimulated by several randomized studies demonstrating the radio-sensitizing effect of hyperthermia, we developed the HYPERcollar. Here, we report early experience and toxicity in patients with advanced HNC.

METHODS AND MATERIALS

119 hyperthermia treatments given to 27 patients were analyzed. Hyperthermia was applied once a week by the HYPERcollar aimed at achieving 39-43 °C in the target area, up to patients' tolerance. Pre-treatment planning was used to optimize treatment settings. When possible, invasive thermometry catheters were placed.

RESULTS

Mean power applied during the 119 hyperthermia treatments ranged from 120 to 1007 W (median 543 W). 15 (13%) hyperthermia treatments were not fully completed due to: pain allocated to hyperthermia (6/15), dyspnea from sticky saliva associated with irradiation (2/15) and unknown reasons (7/15). No severe complications or enhanced thermal or mucosal toxicities were observed. Excluding post-operative treatment, response rates after 3 months were 46% (complete) and 7% (partial).

CONCLUSION

Hyperthermia with the HYPERcollar proved to be safe and feasible with good compliance and promising outcome.

Cost-effectiveness analysis of salvage therapies in locoregional previously irradiated head and neck cancer

BACKGROUND

The purpose of this study was to present our evaluation of the cost-effectiveness of salvage therapies for patients with recurrent head and neck cancer.

METHODS

A Markov model was developed with 5 salvage treatment strategies: (1) platinum-based chemotherapy alone; (2) chemotherapy plus cetuximab; (3) stereotactic body radiotherapy (SBRT) alone; (4) SBRT plus cetuximab; and (5) intensity-modulated radiotherapy (IMRT) plus chemotherapy. Clinical parameters were obtained from comprehensive literature review and 2016 Medicare reimbursement. Strategies were compared using the incremental cost-effectiveness ratio (ICER), with effectiveness in quality-adjusted life years (QALYs), and evaluated with a willingness-to-pay (WTP) threshold of $100 000 per QALY gained.

RESULTS

In the base case analysis, no treatment strategy was cost-effective at a WTP threshold. The most cost-effective therapy was SBRT alone with $150 866 per QALY gained. If median survival of SBRT alone was ≥11 months, SBRT was considered to be cost-effective.

CONCLUSION

None of the treatment strategies were cost-effective. However, SBRT-based reirradiation has potential to be cost-effective.

Head and Neck Tumor Control Probability: Radiation Dose-Volume Effects in Stereotactic Body Radiation Therapy for Locally Recurrent Previously-Irradiated Head and Neck Cancer: Report of the AAPM Working Group

PURPOSE

Stereotactic body radiation therapy (SBRT) has emerged as a viable reirradiation strategy for locally recurrent previously-irradiated head and neck cancer. Doses in the literature have varied, which challenges clinical application of SBRT as well as clinical trial design.

MATERIAL & METHODS

A working group was formed through the American Association of Physicists in Medicine to study tumor control probabilities for SBRT in head and neck cancer. We herein present a systematic review of the available literature addressing the dose/volume data for tumor control probability with SBRT in patients with locally recurrent previously-irradiated head and neck cancer. Dose-response models are generated that present tumor control probability as a function of dose.

RESULTS

Data from more than 300 cases in 8 publications suggest that there is a dose-response relationship, with superior local control and possibly improved overall survival for doses of 35 to 45 Gy (in 5 fractions) compared with <30 Gy.

CONCLUSION

Stereotactic body radiation therapy doses equivalent to 5-fraction doses of 40 to 50 Gy are suggested for retreatment.

Stereotactic Body Radiotherapy Treatment for Recurrent, Previously Irradiated Head and Neck Cancer

Purpose:

Locally recurrent, previously irradiated primary head and neck tumors have historically been associated with poor outcomes. Stereotactic body radiation therapy has emerged as a feasible and promising treatment option for tumor recurrence, particularly in nonsurgical candidates. This study aimed to assess the associated outcomes of stereotactic body radiation therapy used in this setting.

Methods:

Retrospective analysis of a prospectively collected database of 25 patients treated with CyberKnife for unresectable, recurrent head and neck cancer in a previously irradiated field. The primary end points evaluated were rates of survival, tumor control, and treatment-related toxicities.

Results:

Median survival of the study population was 7.5 months (range, 1.5-47.0 months). Median survival of the 20 (80%) patients who were treated with curative purpose was 8.3 months. One-year overall survival rate for the entire population was 32%. The respective 1-year and 2-year survival rates for the curative subcohort were 40% and 20%, respectively. Local and locoregional failure occurred in 8 (32%) and 7 (28%) patients, respectively. Low severe acute (4%) and late (6%) treatment-related toxicity rates were observed. No grade 4 or 5 toxicities were observed.

Conclusion:

Stereotactic body radiation therapy is a viable treatment option for patients with unresectable, recurrent head and neck cancer. Significant tumor control rates are achievable with minimal severe toxicity. Although perhaps associated with patient selection and a heterogeneous sample, overall survival of stereotactic body radiation therapy outcomes appears unfavorable.

Carotid Dosimetry and the Risk of Carotid Blowout Syndrome After Reirradiation With Head and Neck Stereotactic Body Radiation Therapy

PURPOSE

To correlate carotid dose and risk of carotid blowout syndrome (CBOS) after stereotactic body radiation therapy (SBRT), hypothesizing that carotid dose does not correlate with CBOS.

METHODS AND MATERIALS

We retrospectively reviewed 186 patients with recurrent, previously irradiated head and neck cancer treated between January 2008 and March 2013. Patients treated early in our experience with incomplete dosimetry were excluded from analysis (n = 111). A total of 75 patients were identified, providing 150 carotid arteries for analysis. Median follow-up was 8 months (range, 1-91 months) for all patients, and 37 months for surviving patients (range, 31-91 months). Patients were treated with linear accelerator-based SBRT to a median dose up to 44 Gy (range, 40-50 Gy) in 5 fractions delivered on a twice-weekly basis. Concurrent cetuximab was used in 63 patients (84%). The bilateral common, internal, and external carotid arteries were delineated 2 cm above and below the planning target volume. The maximum dose to 0.1 cm³ (D_0.1cc), 1 cm³ (D_1cc), and 2 cm³ (D_2cc) of the carotid and the mean carotid dose from SBRT were recorded and analyzed for association with carotid bleeding events, using binary logistic regression.

RESULTS

Median reirradiation interval was 20 months (range, 3-423 months), and median prior radiation dose was 70 Gy (range, 52.5-140 Gy). Sixteen patients (21.3%) received more than 1 course of SBRT, and the cumulative carotid doses from fused summary plans were recorded. The overall median D_0.1cc, D_1cc, D_2cc, and mean carotid doses were 40.8 Gy (interquartile range [IQR], 21.6-47.6 Gy), 26.8 Gy (IQR, 14.1-42.1 Gy), 15.4 Gy (IQR, 8.4-32.7 Gy), and 15.0 Gy (IQR, 8.9-23.3 Gy), respectively. There were a total of 4 bleeding events (5.3%): 2 patients (2.7%) had mucosal bleeds that resolved after embolization of carotid branches, and 2 patients (2.7%) died from complications of CBOS. In the 2 patients with CBOS the D_0.1cc was 48.4 Gy and 47.6 Gy, respectively. There was no significant association between bleeding events and D_1cc (P = .280), D_2cc (P = .571), or mean dose (P = .568). There was a trend toward increased risk of bleeding and D_0.1cc (P = .080).

CONCLUSIONS

These results demonstrate a low risk of bleeding after reirradiation with SBRT when 5 fractions are delivered on nonconsecutive days, even when tumor is completely encasing the carotid artery. Although limited by the low number of events, no significant association was found between dose-volume parameters and the risk of carotid bleeding. No CBOS was noted when D_0.1cc was <47.6 Gy.

Reirradiation of Skull Base Tumors With Advanced Highly Conformal Techniques

PURPOSE OF REVIEW

Skull base reirradiation is challenging due to complex anatomy, enrichment of treatment-resistant clonogens, and increased risk of severe treatment complications. Without local therapy, early mortality is certain and tumor progression can result in debilitating symptoms. Modern radiotherapy advancements, such as image-guided radiation therapy (IGRT), intensity-modulated radiation therapy (IMRT), particle therapy, and stereotactic radiation therapy (SRT), are attractive for skull base reirradiation.

RECENT FINDINGS

Although limited by their retrospective nature and heterogeneous patient populations, several studies have demonstrated that reirradiation with these highly conformal techniques is feasible. Compared to IMRT or particle therapy reirradiation, SRT reirradiation appears promising with lower toxicity and increased convenience. Here, we provide thorough explanations for each technology and summarize the most relevant and recent studies, with particular attention to efficacy and toxicity. Skull base reirradiation using these extremely conformal therapy techniques requires meticulous treatment planning and should be delivered by experienced teams.

Stereotactic Body Radiation Therapy for Recurrent Head and Neck Cancer

Stereotactic body radiation therapy (SBRT) offers a promising opportunity for cure and/or palliation to patients with recurrent head and neck cancer whose comorbidities, performance status, and history of prior treatment may preclude many other salvage options. Stereotactic body radiation therapy appears to have a favorable response and toxicity profile compared with other nonoperative salvage options for recurrent head and neck cancer. However, the risk of severe toxicity remains, with carotid blowout syndrome a unique concern, although the incidence of this complication may be minimized with alternating-day fractionation. The short overall treatment time and low rates of acute toxicity make SBRT an optimal vehicle to integrate with novel systemic therapies, and several phase II studies have used concurrent cetuximab as a radiosensitizer with SBRT with promising results. Ongoing studies aim to evaluate the potential synergistic effect of SBRT with immune checkpoint inhibitors in recurrent head and neck cancer.

Effect of intratumoral abscess/necrosis on the outcome for head and neck cancer patients treated by hypofractionated stereotactic re-irradiation using CyberKnife®

The aim of the present study was to elucidate the effect of intratumoral abscess/necrosis (AN) on the outcome of patients with recurrent head and neck cancer (HNC) treated by stereotactic radiotherapy. The records of 67 patients treated with CyberKnife® in four institutes between August 2000 and July 2010 were reviewed. The frequency of AN appeared to be increased in younger postoperative patients with large ulcerative tumors. The AN⁺ group exhibited a better initial response rate compared with the AN⁻ group (64 vs. 33%, respectively; P=0.04). The 1-year local control rate was 51 and 75% in the AN⁺ and AN⁻ groups, respectively (P=0.01), while the respective 1-year overall survival rates were 53 and and 71% (P=0.0004). A total of 21 patients (31%) experienced grade ≥3 toxicities, and carotid blowout syndrome (CBOS) was found in 11 patients, resulting in 8 deaths. A significantly larger proportion of patients in the AN⁺ group developed CBOS (8/18; 44%) compared with the AN⁻ group (3/49; 6%) (P=0.001). Therefore, AN may be an important prognostic factor for patients with recurrent HNC, as well as a predictor of lethal toxicity due to CBOS.

Risk of carotid blowout after reirradiation with particle therapy

Purpose

Carotid blowout (CB) is a serious complication in retreatment of neoplasms in the head and neck (H&N) region. Rates seem to increase in hypofractionated or accelerated hyperfractionated regimens. In this study, we investigate the CB rate and the cumulative doses received by the carotid artery (CA) in a cohort of patients who were reirradiated at CNAO with particle therapy in the H&N region.

Methods and materials

The dosimetric information, medical records, and tumor characteristics of 96 patients were analyzed. For 49 of these patients, the quality of dosimetric information was sufficient to calculate the cumulative doses to the CA. The corresponding biological equivalent dose in 2 Gy fractions (EQD2) was calculated with an α/β-ratio of 3.

Results

In the final reirradiation at CNAO, 17 patients (18%) had been treated with protons and 79 (82%) with carbon ions. Two patients experienced profuse oronasal bleeding, of which one case was confirmed to be caused by CB. If attributing both cases to CB, we found an actuarial CB rate of 2.7%. Interestingly, there were no CB cases in the carbon ion group even though this was the large majority of patients and they generally were treated more aggressively in terms of larger fraction doses and higher cumulative EQD2.

Conclusions

The current practice of particle reirradiation at CNAO for recurrent neoplasms in the H&N region results in acceptable rates of CB.