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.
This narrative review of osteonecrosis of the jaw in patients with low bone mass receiving treatment with antiresorptive agents is based on an appraisal of the literature by an advisory committee of ...the American Dental Association Council on Scientific Affairs. It updates the committee's 2008 advisory statement.
The authors searched MEDLINE for literature published between May 2008 (the end date of the last search) and February 2011.
This report contains recommendations based on the findings of the literature search and on expert opinion that relate to general dentistry; periodontal disease management; implant placement and maintenance; oral and maxillofacial surgery; endodontics; restorative dentistry and prosthodontics; orthodontics; and C-terminal telopeptide testing and drug holidays.
The highest reliable estimate of antiresorptive agent-induced osteonecrosis of the jaw (ARONJ) prevalence is approximately 0.10 percent. Osteoporosis is responsible for considerable morbidity and mortality. Therefore, the benefit provided by antiresorptive therapy outweighs the low risk of developing osteonecrosis of the jaw.
An oral health program consisting of sound hygiene practices and regular dental care may be the optimal approach for lowering ARONJ risk. No validated diagnostic technique exists to determine which patients are at increased risk of developing ARONJ. Discontinuing bisphosphonate therapy may not lower the risk but may have a negative effect on low-bone-mass-treatment outcomes.
The purpose of this study was to analyze results of adjuvant stereotactic radiosurgery (SRS) targeted at resection cavities of brain metastases without whole-brain irradiation (WBI).
Patients who ...underwent SRS to the tumor bed, deferring WBI after resection of a brain metastasis, were retrospectively identified.
Seventy-two patients with 76 cavities treated from 1998 to 2006 met inclusion criteria. The SRS was delivered to a median marginal dose of 18.6 Gy (range, 15-30 Gy) targeting an average tumor volume of 9.8 cm(3) (range, 0.1-66.8 cm(3)). With a median follow-up of 8.1 months (range, 0.1-80.5 months), 65 patients had follow-up imaging assessable for control analyses. Actuarial local control rates at 6 and 12 months were 88% and 79%, respectively. On univariate analysis, increasing values of conformality indices were the only treatment variables that correlated significantly with improved local control; local control was 100% for the least conformal quartile compared with 63% for the remaining quartiles. Target volume, dose, and number of sessions were not statistically significant.
In this retrospective series, SRS administered to the resection cavity of brain metastases resulted in a 79% local control rate at 12 months. This value compares favorably with historic results with observation alone (54%) and postoperative WBI (80-90%). Given the improved local control seen with less conformal plans, we recommend inclusion of a 2-mm margin around the resection cavity when using this technique.
Given the neurocognitive toxicity associated with whole-brain irradiation (WBRT), approaches to defer or avoid WBRT after surgical resection of brain metastases are desirable. Our initial experience ...with stereotactic radiosurgery (SRS) targeting the resection cavity showed promising results. We examined the outcomes of postoperative resection cavity SRS to determine the effect of adding a 2-mm margin around the resection cavity on local failure (LF) and toxicity.
We retrospectively evaluated 120 cavities in 112 patients treated from 1998-2009. Factors associated with LF and distant brain failure (DF) were analyzed using competing risks analysis, with death as a competing risk. The overall survival (OS) rate was calculated by the Kaplan-Meier product-limit method; variables associated with OS were evaluated using the Cox proportional hazards and log rank tests.
The 12-month cumulative incidence rates of LF and DF, with death as a competing risk, were 9.5% and 54%, respectively. On univariate analysis, expansion of the cavity with a 2-mm margin was associated with decreased LF; the 12-month cumulative incidence rates of LF with and without margin were 3% and 16%, respectively (P=.042). The 12-month toxicity rates with and without margin were 3% and 8%, respectively (P=.27). On multivariate analysis, melanoma histology (P=.038) and number of brain metastases (P=.0097) were associated with higher DF. The median OS time was 17 months (range, 2-114 months), with a 12-month OS rate of 62%. Overall, WBRT was avoided in 72% of the patients.
Adjuvant SRS targeting the resection cavity of brain metastases results in excellent local control and allows WBRT to be avoided in a majority of patients. A 2-mm margin around the resection cavity improved local control without increasing toxicity compared with our prior technique with no margin.
We sought to determine the risk of leptomeningeal disease (LMD) in patients treated with stereotactic radiosurgery (SRS) targeting the postsurgical resection cavity of a brain metastasis, deferring ...whole-brain radiation therapy (WBRT) in all patients.
We retrospectively reviewed 175 brain metastasis resection cavities in 165 patients treated from 1998 to 2011 with postoperative SRS. The cumulative incidence rates, with death as a competing risk, of LMD, local failure (LF), and distant brain parenchymal failure (DF) were estimated. Variables associated with LMD were evaluated, including LF, DF, posterior fossa location, resection type (en-bloc vs piecemeal or unknown), and histology (lung, colon, breast, melanoma, gynecologic, other).
With a median follow-up of 12 months (range, 1-157 months), median overall survival was 17 months. Twenty-one of 165 patients (13%) developed LMD at a median of 5 months (range, 2-33 months) following SRS. The 1-year cumulative incidence rates, with death as a competing risk, were 10% (95% confidence interval CI, 6%-15%) for developing LF, 54% (95% CI, 46%-61%) for DF, and 11% (95% CI, 7%-17%) for LMD. On univariate analysis, only breast cancer histology (hazard ratio, 2.96) was associated with an increased risk of LMD. The 1-year cumulative incidence of LMD was 24% (95% CI, 9%-41%) for breast cancer compared to 9% (95% CI, 5%-14%) for non-breast histology (P=.004).
In patients treated with SRS targeting the postoperative cavity following resection, those with breast cancer histology were at higher risk of LMD. It is unknown whether the inclusion of whole-brain irradiation or novel strategies such as preresection SRS would improve this risk or if the rate of LMD is inherently higher with breast histology.
Generation of digitally reconstructed radiographs (DRRs) is computationally expensive and is typically the rate-limiting step in the execution time of intensity-based two-dimensional to ...three-dimensional (2D-3D) registration algorithms. We address this computational issue by extending the technique of light field rendering from the computer graphics community. The extension of light fields, which we call attenuation fields (AFs), allows most of the DRR computation to be performed in a preprocessing step; after this precomputation step, DRRs can be generated substantially faster than with conventional ray casting. We derive expressions for the physical sizes of the two planes of an AF necessary to generate DRRs for a given X-ray camera geometry and all possible object motion within a specified range. Because an AF is a ray-based data structure, it is substantially more memory efficient than a huge table of precomputed DRRs because it eliminates the redundancy of replicated rays. Nonetheless, an AF can require substantial memory, which we address by compressing it using vector quantization. We compare DRRs generated using AFs (AF-DRRs) to those generated using ray casting (RC-DRRs) for a typical C-arm geometry and computed tomography images of several anatomic regions. They are quantitatively very similar: the median peak signal-to-noise ratio of AF-DRRs versus RC-DRRs is greater than 43 dB in all cases. We perform intensity-based 2D-3D registration using AF-DRRs and RC-DRRs and evaluate registration accuracy using gold-standard clinical spine image data from four patients. The registration accuracy and robustness of the two methods is virtually identical whereas the execution speed using AF-DRRs is an order of magnitude faster.
To report the outcomes of repeat stereotactic radiosurgery (SRS), deferring whole-brain radiation therapy (WBRT), for distant intracranial recurrences and identify factors associated with prolonged ...overall survival (OS).
We retrospectively identified 652 metastases in 95 patients treated with 2 or more courses of SRS for brain metastases, deferring WBRT. Cox regression analyzed factors predictive for OS.
Patients had a median of 2 metastases (range, 1-14) treated per course, with a median of 2 courses (range, 2-14) of SRS per patient. With a median follow-up after first SRS of 15 months (range, 3-98 months), the median OS from the time of the first and second course of SRS was 18 (95% confidence interval CI 15-24) and 11 months (95% CI 6-17), respectively. On multivariate analysis, histology, graded prognostic assessment score, aggregate tumor volume (but not number of metastases), and performance status correlated with OS. The 1-year cumulative incidence, with death as a competing risk, of local failure was 5% (95% CI 4-8%). Eighteen (24%) of 75 deaths were from neurologic causes. Nineteen patients (20%) eventually received WBRT. Adverse radiation events developed in 2% of SRS sites.
Multiple courses of SRS, deferring WBRT, for distant brain metastases after initial SRS, seem to be a safe and effective approach. The graded prognostic assessment score, updated at each course, and aggregate tumor volume may help select patients in whom the deferral of WBRT might be most beneficial.
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