Stereotactic Body Radiotherapy (SBRT) for primary and recurrent head and neck tumors

Design, Synthesis and Anticancer Evaluation of Nitroimidazole Radiosensitisers

The role of hypoxic tumour cells in resistance to radiotherapy, and in suppression of immune response, continues to endorse tumour hypoxia as a bona fide, yet largely untapped, drug target. Radiotherapy innovations such as stereotactic body radiotherapy herald new opportunities for classical oxygen-mimetic radiosensitisers. Only nimorazole is used clinically as a radiosensitiser, and there is a dearth of new radiosensitisers in development. In this report, we augment previous work to present new nitroimidazole alkylsulfonamides and we document their cytotoxicity and ability to radiosensitise anoxic tumour cells in vitro. We compare radiosensitisation with etanidazole and earlier nitroimidazole sulfonamide analogues and we identify 2-nitroimidazole and 5-nitroimidazole analogues with marked tumour radiosensitisation in ex vivo assays of surviving clonogens and with in vivo tumour growth inhibition.

Canine oral squamous cell carcinoma as a spontaneous, translational model for radiation and immunology research

Introduction

Improving outcomes for oral squamous cell carcinoma (OSCC) patients has been hindered by a lack of effective predictive animal models. Spontaneously occurring canine OSCC could help fill this gap. The objective of this study was to characterize the immune landscape of canine OSCC to advance understanding of how dogs could serve as a surrogate for human OSCC.

Methods/Results

Canine OSCC contains a heterogenous tumor immune microenvironment. CD3+ T cells were the predominant tumor infiltrating immune cell population; however, there was a wide range CD3+ T cell density across samples. The most common CD3+ T cell micro-anatomical distribution was defined as "pre-existing immunity", but the remaining 20% of tumors were characterized as "immunologically ignorant" or "excluded infiltrates" patterns. When compared to normal oral mucosa, the tumor gene expression pattern suggests that canine OSCC microenvironment is highly inflamed and characterized by the presence of an anti-tumor immune response dominated by cytotoxic\effector T cells and NK cells (CD8a, GZMA, OX40, and HLA-A); however, overexpression of genes associated with effector T cell exhaustion and microenvironmental immunosuppression was also identified (PD-1, LAG3, CXCL2). Correlations between CD3+ T cell density and immune gene expression revealed key genes associated with cytotoxic anti-tumor T cell responses (GZMA, GZMB, PRF1), co-stimulation of T cells (CD27, CD28, ICOS), and other immune processes, including Type I IFN response (TNF, TNFSF10), and T cell exhaustion (CTLA4, PD-1). CD3+ T cell density in canine OSCC was significantly correlated with a cytolytic activity score (mean PRF1 and GZMA expression), suggestive of active effector CD8 T cell function. CD204+ macrophages were the second most abundant tumor infiltrating immune cell, and when comparing to normal oral mucosa, two differently expressed genes linked to tumor associated macrophages and myeloid derived suppressor cells (MDSC) were identified: CXCL2, CD70. Overexpression of CXCL2 was also identified in canine OSCC "T cell-high" tumors compared to "T cell-low" tumors.

Discussion

This study identified actionable immunotherapy targets which could inform future comparative oncology trials in canine OSCC: CTLA-4, PD-1, CXCL2. These data provide a good first step towards utilizing spontaneous canine OSCC as a comparative model for human OSCC radiation and immuno-oncology research.

Intensity-modulated radiotherapy with planned Gamma Knife radiosurgery boost for head and neck cancer with extensive disease in proximity to critical structures

BACKGROUND

To describe intensity-modulated radiotherapy (IMRT) with Gamma Knife Radiosurgery (GKRS) boost for locally advanced head and neck cancer (HNC) with disease near dose-limiting structures.

METHODS

Patients with HNC treated with IMRT/GKRS as part of a combined modality approach between 2011 and 2021 were reviewed. Local control, overall survival and disease-specific survival were estimated using the Kaplan Meier method.

RESULTS

Twenty patients were included. Nineteen patients had T3-4 tumors. Median follow-up was 26.3 months. GKRS site control was 95%. Two patients progressed at the treated primary site, one patient failed at the edge of the GKRS treatment volume, with no perineural or intracranial failure. 2-year OS was 94.7% (95% CI: 85.2%-100%). Concurrent chemotherapy was given in nine patients (45%). One patient (5%) received induction/concurrent chemotherapy. Brain radionecrosis occurred in three patients, one of which was biopsy-proven.

CONCLUSIONS

IMRT plus GKRS boost results in excellent disease control near critical structures with minimal toxicity.

Stereotactic partial breast irradiation in primary breast cancer: A comprehensive review of the current status and future directions

In selected low-risk breast cancer patients, accelerated partial breast irradiation (APBI) may represent an alternative option to the whole breast irradiation to reduce the volume of irradiated breast and total treatment duration. In the last few years, preliminary data from clinical trials showed that stereotactic partial breast radiotherapy may have the advantage to be less invasive compared to other APBI techniques, with preliminary good results in terms of local toxicity and cosmesis: the use of magnetic resonance, fiducial markers in the tumor bed, and new breast devices support both a precise definition of the target and radiation planning.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021257856, identifier CRD42021257856.

Stereotactic body radiotherapy plus cetuximab for previously irradiated un-resectable head and neck cancer

BACKGROUND

The aim of the study was to explore the treatment outcomes and prognostic factors for patients with previously irradiated but unresectable recurrent head and neck squamous cell carcinoma (rHNSCC) treated by stereotactic body radiotherapy (SBRT) plus cetuximab at a single institute in Taiwan.

METHODS

From February 2016 to March 2019, 74 patients with previously irradiated but unresectable rHNSCC were treated with SBRT plus cetuximab. All patients received irradiation to the gross tumor and/or nodal area with 40-50 Gy in five fractions, with each fraction interval ≥ 2 days over a 2-week period by using the CyberKnife M6 machine. An¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) scan was performed before treatment for treatment target delineation (n = 74) and 2 months later for response evaluation (n = 60). The median follow-up time was 9 months (range 1-36 months).

RESULTS

The treatment response rate was complete response: 25.0%, partial response: 41.7%, stable disease: 11.7%, and progressive disease: 21.7% based on the criteria of the Response Evaluation Criteria in Solid Tumors (n = 72) and complete metabolic response: 21.7%, partial metabolic response: 51.7%, stable metabolic disease: 13.3%, and progressive metabolic disease: 13.3% based on PET-CT (n = 60), respectively. The 1-/2-year overall survival (OS) and progression-free survival (PFS) rates were 42.8%/22.0% and 40.5%/19.0%, respectively. In the logistic regression model, a re-irradiation interval > 12 months was observed to be the only significant prognostic factor for a favorable treatment response. In the Cox proportional hazards model, a re-irradiation interval > 12 months and gross tumor volume (GTV) ≦ 50 ml were favorable prognostic factors of OS and PFS.

CONCLUSION

SBRT plus cetuximab provides a promising salvage strategy for those patients with previously irradiated but unresectable rHNSCC, especially those with a re-irradiation interval > 12 months or GTV ≦ 50 ml.

A Systematic Review on Re-irradiation with Charged Particle Beam Therapy in the Management of Locally Recurrent Skull Base and Head and Neck Tumors

Purpose

To evaluate the clinical outcomes and treatment related toxicities of charged particle-based re-irradiation (reRT; protons and carbon ions) for the definitive management of recurrent or second primary skull base and head and neck tumors.

Materials and Methods

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were applied for the conduct of this systematic review. Published work in English language evaluating the role of definitive charged particle therapies in the clinical setting of reRT for recurrent or second primary skull base and head and neck tumors were eligible for this analysis.

Results

A total of 26 original studies (15 protons, 10 carbon ions, and 1 helium/neon studies) involving a total of 1,118 patients (437 with protons, 670 with carbon ions, and 11 with helium/neon) treated with curative-intent charged particle reRT were included in this systematic review. All studies were retrospective in nature, and the majority of them (n=23, 88 %) were reported as single institution experiences (87% for protons, and 90% for carbon ion-based studies). The median proton therapy reRT dose was 64.5 Gy (RBE 1.1) (range, 50.0 – 75.6 Gy ), while the median carbon ion reRT dose was 53.8 Gy (RBE 2.5 – 3.0) (range, 44.8 – 60 Gy ). Induction and/or concurrent chemotherapy was administered to 232 (53%) of the patients that received a course of proton reRT, and 122 (18%) for carbon ion reRT patients. ReRT with protons achieved 2-year local control rates ranging from 50% to 86%, and 41% to 92% for carbon ion reRT. The 2-year overall survival rates for proton and carbon ion reRT ranged from 33% to 80%, and 50% to 86% respectively. Late ≥ G3 toxicities ranged from 0% to 37%, with brain necrosis, ototoxicity, visual deficits, and bleeding as the most common complications. Grade 5 toxicities for all treated patients occurred in 1.4% (n= 16/1118) with fatal bleeding as the leading cause.

Conclusions

Based on current data, curative intent skull base and head and neck reRT with charged particle radiotherapy is feasible and safe in well-selected cases, associated with comparable or potentially improved local control and toxicity rates compared to historical reRT studies using photon radiotherapy. Prospective multi-institutional studies reporting oncologic outcomes, toxicity, and dosimetric treatment planning data are warranted to further validate these findings and to improve the understanding of the clinical benefits of charged particle radiotherapy in the reRT setting.

Highlights on the Management of Oligometastatic Disease

Purpose: The understanding of oligometastatic disease (OMD) is rapidly evolving and with this comes the ability to utilize a number of modalities that excel in the localized control of disease. It has been identified that there are no clear guidelines based on high-level evidence to standardized approaches toward the management of OMD. These highlights have been developed to provide a road map for all health-care professionals who are involved in the management of OMD to support standardized patient care. Methods: The Saudi Lung Cancer Guidelines Committee is a part of the Saudi Lung Cancer Association which, in turn, is part of the Saudi Thoracic Society. Considering that lung cancer constitutes a major proportion of OMD prevalence, the committee took the initiative to develop national highlights to support the management of OMD within Saudi Arabia. The committee members are national clinical leaders who collaborated with international expertise to establish these highlights to serve as a general clinical pathway in the management of OMD. Results: Standardization of the indications to diagnose oligometastases and patient selection criteria including ineligibility criteria for treatment are the basis of the highlights. Treatment approaches including surgical and the variety of radiotherapeutical options are discussed in relation to specific oligometastatic sites. Acceptable measurements for response to treatment and the future for the treatment of OMD conclude the development of the highlights. Conclusion: These are the first national highlights addressing this important disease in oncology. The implementation of these highlights as guidelines requires a robust multidisciplinary team and access to specific technology and expertise. These highlights are based on the most recent findings within the literature but will require repeated review and updating due to this rapidly evolving field in disease management.

Stereotactic body radiation therapy in primary hepatocellular carcinoma: current status and future directions

Stereotactic body radiation therapy (SBRT) is a form of radiation therapy that has been used in the treatment of primary hepatocellular carcinoma (HCC) over the past decade. To evaluate the clinical efficacy of SBRT in primary HCC, a literature search was conducted to identify original research articles published from January 2000 through January 2018 in PubMed on SBRT in HCC. All relevant studies published from 2004 to 2018 were included. Prospective studies demonstrated 2-year local control (LC) rates ranging from 64-95% and overall survival (OS) rates ranging from 34% (2-year) to 65% (3-year). Retrospective studies demonstrated 2-year LC rates of 44-90% and 2-year OS rates of 24-67%. Reported toxicities in primary HCC patients vary but SBRT appears to be relatively well tolerated. Studies comparing SBRT to radiofrequency ablation (RFA) are few, but they suggest SBRT may be more effective than RFA in specific primary HCC populations. Additionally, SBRT appears to increase the efficacy of both transarterial chemoembolization (TACE) and sorafenib in selected primary HCC populations.

Dose-dependent enhancement of T-lymphocyte priming and CTL lysis following ionizing radiation in an engineered model of oral cancer

OBJECTIVES

Determine if direct tumor cell cytotoxicity, antigen release, and susceptibility to T-lymphocyte killing following radiation treatment is dose-dependent.

MATERIALS AND METHODS

Mouse oral cancer cells were engineered to express full-length ovalbumin as a model antigen. Tumor antigen release with uptake and cross presentation of antigen by antigen presenting cells with subsequent priming and expansion of antigen-specific T-lymphocytes following radiation was modeled in vitro and in vivo. T-lymphocyte mediated killing was measured following radiation treatment using a novel impedance-based cytotoxicity assay.

RESULTS

Radiation treatment induced dose-dependent induction of executioner caspase activity and apoptosis in MOC1 cells. In vitro modeling of antigen release and T-lymphocyte priming demonstrated enhanced proliferation of OT-1 T-lymphocytes with 8Gy treatment of MOC1ova cells compared to 2Gy. This was validated in vivo following treatment of established MOC1ova tumors and adoptive transfer of antigen-specific T-lymphocytes. Using a novel impedance-based cytotoxicity assay, 8Gy enhanced tumor cell susceptibility to T-lymphocyte killing to a greater degree than 2Gy.

CONCLUSION

In the context of using clinically-relevant doses of radiation treatment as an adjuvant for immunotherapy, 8Gy is superior to 2Gy for induction of antigen-specific immune responses and enhancing tumor cell susceptibility to T-lymphocyte killing. These findings have significant implications for the design of trials combining radiation and immunotherapy.

Improved setup and positioning accuracy using a three-point customized cushion/mask/bite-block immobilization system for stereotactic reirradiation of head and neck cancer

The purpose of this study was to investigate the setup and positioning uncertainty of a custom cushion/mask/bite‐block (CMB) immobilization system and determine PTV margin for image‐guided head and neck stereotactic ablative radiotherapy (HN‐SABR). We analyzed 105 treatment sessions among 21 patients treated with HN‐SABR for recurrent head and neck cancers using a custom CMB immobilization system. Initial patient setup was performed using the ExacTrac infrared (IR) tracking system and initial setup errors were based on comparison of ExacTrac IR tracking system to corrected online ExacTrac X‐rays images registered to treatment plans. Residual setup errors were determined using repeat verification X‐ray. The online ExacTrac corrections were compared to cone‐beam CT (CBCT) before treatment to assess agreement. Intrafractional positioning errors were determined using prebeam X‐rays. The systematic and random errors were analyzed. The initial translational setup errors were −0.8±1.3 mm, −0.8±1.6 mm, and 0.3±1.9 mm in AP, CC, and LR directions, respectively, with a three‐dimensional (3D) vector of 2.7±1.4 mm. The initial rotational errors were up to 2.4° if 6D couch is not available. CBCT agreed with ExacTrac X‐ray images to within 2 mm and 2.5°. The intrafractional uncertainties were 0.1±0.6 mm, 0.1±0.6 mm, and 0.2±0.5 mm in AP, CC, and LR directions, respectively, and 0.0∘±0.5°, 0.0∘±0.6°, and −0.1∘±0.4∘ in yaw, roll, and pitch direction, respectively. The translational vector was 0.9±0.6 mm. The calculated PTV margins mPTV(90,95) were within 1.6 mm when using image guidance for online setup correction. The use of image guidance for online setup correction, in combination with our customized CMB device, highly restricted target motion during treatments and provided robust immobilization to ensure minimum dose of 95% to target volume with 2.0 mm PTV margin for HN‐SABR.

PACS number(s): 87.55.ne

Outcomes of patients with loco-regionally recurrent or new primary squamous cell carcinomas of the head and neck treated with curative intent reirradiation at Mayo Clinic

BACKGROUND

We reviewed outcomes of patients with loco-regionally recurrent (LRR) or new primary (NP) squamous cell carcinoma of the head and neck (SCCHN) treated at our institution with reirradiation (RRT).

METHODS

Patients received definitive RRT (DRRT) or post-operative RRT following salvage surgery (PRRT) from 2003 to 2011. Measured survival outcomes included loco-regional relapse free survival (LRFS) and overall survival (OS).

RESULTS

Among 81 patients (PRRT, 42; DRRT, 39), median PRRT and DRRT doses were 60 Gy (12-70 Gy) and 69.6 Gy (48-76.8 Gy). The majority of patients received IMRT-based RRT (n = 77, 95 %). With median follow-up of 78.1 months (95 % CI, 56-96.8 months), 2-year OS was 53 % with PRRT and 48 % with DRRT (p = 0.12); 23 % of patients were alive at last follow-up. LRFS at 2 years was 60 %, and did not differ significantly between PRRT and DRRT groups. A trend toward inferior LRFS was noted among patients receiving chemotherapy with RRT versus RRT alone (p = 0.06). Late serious toxicities were uncommon, including osteoradionecrosis (2 patients) and carotid artery bleeding (1 patient, non-fatal).

CONCLUSIONS

OS of PRRT- and DRRT-treated patients in this series appears superior to the published literature. We used IMRT for the majority of patients, in contrast to several series and trials previously reported, which may account in part for this difference. Future studies should seek to improve outcomes among patients with LRR/NP SCCHN via alternative therapeutic modalities such as proton radiotherapy and by incorporating novel systemic agents.

Stereotactic ablative radiosurgery for locally advanced or recurrent skull base malignancies with prior external beam radiation therapy

PURPOSE

Stereotactic ablative radiotherapy (SABR) is an attractive modality to treat malignancies invading the skull base as it can deliver a highly conformal dose with minimal toxicity. However, variation exists in the prescribed dose and fractionation. The purpose of our study is to examine the local control, survival, and toxicities in SABR for the treatment of previously irradiated malignant skull base tumors.

MATERIALS AND METHODS

A total of 31 patients and 40 locally advanced or recurrent head and neck malignancies involving the skull base treated with a common SABR regimen, which delivers a radiation dose of 44 Gy in 5 fractions from January 1st, 2004 to December 31st, 2013, were retrospectively reviewed. The local control rate (LC), progression-free survival rate, overall survival (OS) rate, and toxicities were reported.

RESULTS

The median follow-up time of all patients was 11.4 months (range: 0.6-67.2 months). The median tumor volume was 27 cm(3) (range: 2.4-205 cm(3)). All patients received prior external beam radiation therapy with a median radiation dose of 64 Gy (range: 24-75.6 Gy) delivered in 12-42 fractions. Twenty patients had surgeries prior to SABR. Nineteen patients received chemotherapy. Specifically, eight patients received concurrent cetuximab (Erbitux™) with SABR. The median time-to-progression (TTP) was 3.3 months (range: 0-16.9 months). For the 29 patients (93.5%) who died, the median time from the end of first SABR to death was 10.3 months (range: 0.5-41.4 months). The estimated 1-year OS rate was 35%. The estimated 2-year OS rate was 12%. Treatment was well-tolerated without grade 4 or 5 treatment-related toxicities.

CONCLUSION

Stereotactic ablative radiotherapy has been shown to achieve low toxicities in locally advanced or recurrent, previously irradiated head and neck malignancies invading the skull base.

Radiation oncology: physics advances that minimize morbidity

ABSTRACT 

Radiation therapy has become an ever more successful treatment for many cancer patients. This is due in large part from advances in physics including the expanded use of imaging protocols combined with ever more precise therapy devices such as linear and particle beam accelerators, all contributing to treatments with far fewer side effects. This paper will review current state-of-the-art physics maneuvers that minimize morbidity, such as intensity-modulated radiation therapy, volummetric arc therapy, image-guided radiation, radiosurgery and particle beam treatment. We will also highlight future physics enhancements on the horizon such as MRI during treatment and intensity-modulated hadron therapy, all with the continued goal of improved clinical outcomes.

Stereotactic body radiotherapy as primary therapy for head and neck cancer in the elderly or patients with poor performance

OBJECTIVE

Stereotactic body radiotherapy (SBRT) is increasingly used to treat a variety of tumors, including head and neck squamous cell carcinoma (HNSCC) in the recurrent setting. While there are published data for re-irradiation using SBRT for HNSCC, there are limited data supporting its use as upfront treatment for locally advanced disease.

STUDY DESIGN/METHODS

Here, we describe three patients who received SBRT as the primary treatment for their HNSCC along with a review of the current literature and discussion of future pathways.

RESULTS

The three cases discussed tolerated treatment well with manageable acute toxicities and had either a clinical or radiographic complete response to therapy.

CONCLUSION

Head and neck squamous cell carcinoma presents a unique challenge in the elderly, where medical comorbidities make it difficult to tolerate conventional radiation, often given with a systemic sensitizer. For these individuals, providing a shortened course using SBRT may offer an effective alternative.

Current approaches and recent developments in the management of head and neck paragangliomas

Head and neck paragangliomas (HNPGLs) are rare neuroendocrine tumors belonging to the family of pheochromocytoma/paraganglioma neoplasms. Despite advances in understanding the pathogenesis of these tumors, the growth potential and clinical outcome of individual cases remains largely unpredictable. Over several decades, surgical resection has long been the treatment of choice for HNPGLs. However, increasing experience in various forms of radiosurgery has been reported to result in curative-like outcomes, even for tumors localized in the most inaccessible anatomical areas. The emergence of such new therapies challenges the traditional paradigm for the management of HNPGLs. This review will assist and guide physicians who encounter patients with such tumors, either from a diagnostic or therapeutic standpoint. This review will also particularly emphasize current and emerging knowledge in genetics, imaging, and therapeutic options as well as the health-related quality of life for patients with HNPGLs.

Stereotactic body radiotherapy for a large arteriovenous malformation of the head and neck

Large arteriovenous malformations (AVMs) of the head and neck present a treatment challenge. A 38-year-old woman presented with a large intraoral bleed from longstanding AVMs of the left infratemporal fossa and the right tongue, despite 10 prior surgeries and embolizations. She was treated with stereotactic body radiotherapy with a dose of 24 Gy in three weekly fractions. Four years later, she has had dramatic shrinkage of her AVM, no recurrent bleeding episodes, no further treatment required, and no significant late effects. Level of evidence: NA.

Cerebral cyst formation following stereotactic ablative irradiation for non-nasopharyngeal head and neck malignancies: imaging findings and relevant dosimetric parameters

OBJECTIVE

To describe the clinical characteristics, imaging findings and relevant dosimetric parameters of cases presenting with cerebral cyst formation (CCF) after single or oligo-fractionated stereotactic radiotherapy (SRT) for non-nasopharyngeal head and neck malignancies (HNMs).

METHODS

We identified four cases with the follow-up duration of 5.7-9.1 years from SRT. The irradiated sites included the middle ear in one case and the ethmoid sinus in three cases, two of the latter possessed brain invasion. The chronological changes in MR images and the dose-volume histogram of the adjacent brain tissue were evaluated.

RESULTS

CCF with or without multiple septi presented with a latency of 29-86 months (median, 45.5 months), which was preceded by either non-specific parenchymal enhancement or typical radiation necrosis. In three cases, CCF adjacent to the frontal base resultantly caused mass effect, and two of these three cases required surgical intervention at 38 and 54 months, respectively, after SRT for alleviation of symptoms. The relation of the irradiated brain volumes to the biological equivalent dose based on the linear-quadratic (LQ) and LQ-cubic models was represented as a threshold.

CONCLUSION

When contemplating SRT for HNM cases, caution should be exercised to the dose-volume relation-ship of the adjacent brain tissue, especially the frontal base, as well as other critical structures, and long-term vigilant follow-up is also mandatory.

ADVANCES IN KNOWLEDGE

CCF can occur as an unusual consequence of late brain injury with variable but mostly long latency following SRT for non-nasopharyngeal HNMs adjacent to the brain, even superficial parts that were previously irradiated via conventional radiotherapy.