Chemoradiotherapy-related carotid artery inflammation in head and neck cancer patients quantified by [18F]FDG PET/CT.

OBJECTIVES: Radiotherapy (RT) is associated with an increased risk of cardiovascular disease (CVD), but little is known about the mechanism for vascular injury and methods for early detection. MATERIALS AND METHODS: We conducted a prospective, pilot study of carotid artery inflammation using 18F-labeled 2-fluoro-2-deoxy-d-glucose ([18F]FDG) PET/CT imaging pre- and 3 months post-RT in head-and-neck cancer (HNC) patients. [18F]FDG uptake by the carotid arteries was measured by the maximum and mean target to background ratio (TBRMAX, TBRMEAN) and the mean partial volume corrected standardized uptake value (pvcSUVMEAN). RESULTS: Of the 22 patients who completed both pre and post-RT scans, the majority (82%) had stage III or stage IV disease and received concurrent chemotherapy. TBRMAX, TBRMEAN, and pvcSUVMEAN were all significantly higher 3 months after RT versus before RT with mean difference values (95% CI; p-value) of 0.17 (0.1-0.25; 0.0001), 0.19 (0.12-0.25; 0.0001), and 0.31 g/ml (0.12-0.5; 0.002), respectively. Fifteen patients (68%) had HPV-positive tumors, which were associated with lower pre-RT [18F]FDG signal, but a greater increase in TBRMAX (19% vs 5%), TBRMEAN (21% vs 11%) and pvcSUVMEAN (20% increase vs 3% decrease), compared to HPV negativity. CONCLUSION: There is a significant increase in carotid artery inflammation in HNC patients due to CRT that amounts to a degree that has previously been associated with higher risk for future CVD events. The subset of patients with HPV-positive tumors experienced the greatest increases in vascular inflammation due to CRT. Carotid [18F]FDG uptake may be an early biomarker of RT-related vascular injury.

Stereotactic body radiotherapy for benign spinal tumors: Meningiomas, schwannomas, and neurofibromas.

Stereotactic body radiation therapy (SBRT) is a relatively new technology, and its use among patients with benign spinal tumors has limited prospective data. Similar to intracranial benign tumors treated successfully with SBRT, benign spinal tumors of the same histology can also develop, and SBRT may be an effective treatment alternative in inoperable or recurrent cases. Outcomes in patients with neurofibromatosis type 1, neurofibromatosis type 2, or schwannomatosis treated with SBRT have also been reported. Single institution reports have shown local control rates over 90% and improvement in clinical symptoms. The optimum dose and fractionation to maximize local control and minimize toxicity is unknown, with few incidences of radiation treatment-related toxicities. Given the location and benign nature of these tumors, careful management of dose to critical organs is essential. With continued follow-up, the optimum use of SBRT in patients with benign spinal tumors can be better defined.

Cardiovascular risk and prevention in patients with head and neck cancer treated with radiotherapy.

BACKGROUND: The underlying contributors to cardiovascular disease (CVD) in patients with head and neck squamous cell carcinoma (HNSCC) are poorly characterized. METHODS: Patients with HNSCC who underwent definitive or adjuvant (chemo)radiation between 2011 and 2013 were retrospectively reviewed. The 10-year risk estimates for a CVD event were calculated according to the Framingham Risk Score (FRS). RESULTS: One hundred fifteen patients with predominantly stage III/IV HNSCC had a median follow-up of 2 years. At diagnosis, 23% of patients had CVD. The FRS was higher among patients with laryngeal cancer versus other sites (20.5% vs 14.4%). Twenty-four percent of all patients had uncontrolled blood pressure at diagnosis. Among the patients with CVD, 41% were not taking antiplatelet therapy and 30% were not taking statin therapy. Thirty-four percent of patients without CVD had indications for initiating statin therapy. CONCLUSION: Patients with HNSCC have a high baseline CVD risk and many do not receive optimal preventive care. © 2016 Wiley Periodicals, Inc. Head Neck 39: 527-532, 2017.

Comparison of Ray Tracing and Monte Carlo Calculation Algorithms for Thoracic Spine Lesions Treated With CyberKnife-Based Stereotactic Body Radiation Therapy.

Stereotactic body radiation therapy (SBRT) is an emerging technology for the treatment of spinal metastases, although the dosimetric impact of the calculation method on spinal dose distribution is unknown. This study attempts to determine whether CyberKnife (CK)-based SBRT using a Ray Tracing (RyTc) algorithm is comparable dosimetrically to that of Monte Carlo (MC) for thoracic spinal lesions. Our institutional CK-based SBRT database for thoracic spinal lesions was queried and a cohort was generated. Patients were planned using RyTc and MC algorithms using the same beam angles and monitor units. Dose-volume histograms of the planning target volume (PTV), spinal cord, esophagus, and skin were generated, and dosimetric parameters were compared. There were 37 patients in the cohort. The average percentage volume of PTV covered by the prescribed dose with RyTc and MC algorithms was 91.1% and 80.4%, respectively (P < .001). The difference in average maximum spinal cord dose between RyTc and MC plans was significant (1126 vs 1084 cGy, P = .004), with the MC dose ranging from 18.7% below to 13.8% above the corresponding RyTc dose. A small reduction in maximum skin dose was also noted (P = .017), although no difference was seen in maximum esophageal dose (P = .15). Only PTVs smaller than 27 cm(3) were found to correlate with large (>10%) changes in dose to 90% of the volume (P = .014), while no correlates with the average percentage volume of PTV covered by the prescribed dose were demonstrated. For thoracic spinal CK-based SBRT, RyTc computation may overestimate the MC calculated average percentage volume of PTV covered by the prescribed dose and have unpredictable effects on doses to organs at risk, particularly the spinal cord. In this setting, use of RyTc optimization should be limited and always verified with MC.

Complications from Stereotactic Body Radiotherapy for Lung Cancer.

Stereotactic body radiotherapy (SBRT) has become a standard treatment option for early stage, node negative non-small cell lung cancer (NSCLC) in patients who are either medically inoperable or refuse surgical resection. SBRT has high local control rates and a favorable toxicity profile relative to other surgical and non-surgical approaches. Given the excellent tumor control rates and increasing utilization of SBRT, recent efforts have focused on limiting toxicity while expanding treatment to increasingly complex patients. We review toxicities from SBRT for lung cancer, including central airway, esophageal, vascular (e.g., aorta), lung parenchyma (e.g., radiation pneumonitis), and chest wall toxicities, as well as radiation-induced neuropathies (e.g., brachial plexus, vagus nerve and recurrent laryngeal nerve). We summarize patient-related, tumor-related, dosimetric characteristics of these toxicities, review published dose constraints, and propose strategies to reduce such complications.

Divergent management strategies for typical versus atypical carcinoid tumors of the thoracic cavity.

OBJECTIVES: At our institution, limited surgical techniques are reserved only for suspected typical carcinoids, and nodal dissection and multimodality therapy are frequently used for atypical carcinoids. We describe the results of these differing management strategies based on initial clinicopathologic characteristics. METHODS: Retrospective review of patients treated for thoracic carcinoid from 1995 to 2009. Information was abstracted concerning surgical and nonsurgical treatments, pathology results, and outcomes. Event-free and survival endpoints were compared. RESULTS: The median follow-up was 5.0 years (range, 0.5 to 17.4 y). Fifty-two patients underwent resection. The 5-year event-free survival for typical carcinoid patients was 88.2%. Atypical carcinoids had a tendency for nodal involvement (50% vs. 15%) and greater likelihood for disease recurrence, with a 5-year event-free survival of 50%. CONCLUSIONS: These data support the appropriateness of divergent management strategies for typical versus atypical bronchial carcinoids. We propose the following: (1) nonanatomic resection is acceptable only for peripheral typical carcinoids; (2) extended mediastinal dissection should be limited to central presentations, clinically aggressive, or atypical carcinoids; (3) atypical histology, especially with nodal involvement, is prognostic for recurrence and metastasis; (4) nonsurgical therapies only rarely achieve long-term freedom from disease.