Proposed modification to the Shamblin's classification of carotid body tumors: A single-center retrospective experience of 116 tumors

Prevalence, characteristics, evaluation, and management of carotid body tumors: Systematic analysis based on available evidence

OBJECTIVE

Although carotid body tumors (CBTs) are rare, they attract particular attention because of their propensity for malignant transformation and the high surgical risk. Because data are scarce and as it is difficult to achieve a large sample size, no study has yet comprehensively analyzed the characteristics, management, or operative complications of CBTs. Therefore, we collected and analyzed all currently available information on CBTs and used the pooled data to derive quantitative information on disease characteristics and management.

METHODS

We systematically searched PubMed, Embase, the Cochrane Library, and the Web of Science up to December 1, 2022, for studies that investigated the characteristics and management of CBTs. The primary objective was to identify the prevalence of the various characteristics and the incidence of complications. The secondary objective was to compare patients who underwent preoperative embolization (PE) and those who did not (non-PE), as well as to compare patients with different Shamblin grades and those with and without succinate dehydrogenase (SDH) mutations in terms of CBT characteristics and complications. Two reviewers selected studies for inclusion and independently extracted data. All statistical analyses were performed using the standard statistical procedures of Review Manager 5.2 and Stata 12.0.

RESULTS

A total of 155 studies with 9291 patients and 9862 tumors were identified. The pooled results indicated that the median age of patients with CBT was 45.72 years, and 65% were female. The proportion of patients with bilateral lesions was 13%. In addition, 16% of patients had relevant family histories, and the proportion of those with SDH gene mutations was 36%. Sixteen percent of patients experienced multiple paragangliomas, and 12% of CBTs had catecholamine function. The incidence of cranial nerve injury (CNI) was 27%, and 14% of patients suffered from permanent CNI. The incidence rates of operative mortality and stroke were both 1%, and 4% of patients developed transient ischemic attacks. Of all CBTs, 6% were malignant or associated with metastases or recurrences. The most common metastatic locations were the lymph nodes (3%) and bone (3%), followed by the lungs (2%). Compared with non-PE, PE reduced the estimated blood loss (standardized mean difference, -0.95; 95% confidence interval [CI], -1.70 to -0.20) and the operation time (standardized mean difference, -0.56; 95% CI, -1.03 to -0.09), but it increased the incidence of stroke (odds ratio, 2.44; 95% CI, 1.04-5.73). Higher Shamblin grade tumors were associated with more operative complications. Patients who were SDH gene mutation-positive were more likely to have a relevant family history and had more symptoms.

CONCLUSIONS

CBT was most common in middle-aged females, and early surgical resection was feasible; there was a low incidence of serious operative complications. Routine PE is not recommended because this may increase the incidence of stroke, although PE somewhat reduced the estimated blood loss and operation time. Higher Shamblin grade tumors increased the incidence of operative complications. Patients who were SDH gene mutation-positive had the most relevant family histories and symptoms.

Paragangliomas of the Head and Neck: A Review of the Latest Diagnostic and Treatment Methods

Background and objectives: Paragangliomas of the head and neck are rare, slow-growing neuroendocrine tumors, benign in their vast majority, but with a possibility of developing distant metastases. They show great inheritable character, and their behavior has proven to be unpredictable; therefore, they are considered malignant. Material and methods: This article aims to offer a more comprehensive presentation of the pathogenesis, epidemiology, diagnostic methods, imaging development, and treatment guidelines. We tried to bring together all the necessary data that, in our opinion, a head and neck practitioner should know when managing this type of tumor. Our main focus is on the most recent studies, with the purpose of a homogenous presentation of all current guidelines and approaches to this pathology. Results: Paragangliomas of the head and neck are still a disputed topic. One of the main reasons for that is their low incidence of 0.3 to 1 per 100,000 every year. The most frequent locations are the carotid body, the temporal bone, the jugular and mastoid foramen, and the vagal nerve. Their clinical presentation usually involves a painless lateral mass associated with symptoms such as hoarseness, hearing loss, tinnitus, and cranial nerve deficits. Up to 40% of them are inherited, mostly linked with mutations of succinate dehydrogenase complex. Imaging evaluation consists of CT and MRI, and new functional explorations such as 18F-FDA and 18F-FDG PET/CT, 18F-DOPA PET, 123I-MIBG, and 68Ga-DOTATE PET/CT. Measuring the catecholamine levels in the plasma and urine is mandatory, even though paragangliomas of the head and neck rarely display secretory behavior. Treatment mainly consists of surgery, with different approaches and techniques, but conservative management methods such as wait and scan, radiotherapy, proton therapy, and chemotherapy have proven their efficiency. The therapeutical decision lacks consensus, and current studies tend to recommend an individualized approach. Guidelines regarding long-term follow-up are still a matter of debate.

Novel insights into the classification of Shamblin III carotid body tumors from a neurosurgical perspective

BACKGROUND AND PURPOSE

The classic Shamblin system fails to provide valuable guidance in many Shamblin's III carotid body tumors (III-CBTs) due to the variable forms of carotid arteries and the complex anatomic relationships in parapharyngeal space. We proposed a modified classification to separately divide III-CBTs into different subgroups on the basis of arterial relevant features and anatomical relevant features.

MATERIALS AND METHODS

From 2020 to 2023, a total of 129 III-CBTs at a single institution were retrospectively analyzed. All cases were independently classified as arterial-relevant and anatomical-relevant subgroups. The pre-, peri- and postoperative data were summarized and compared accordingly.

RESULTS

Among the 129 cases, 69 cases were identified as "Classical type", 23 cases as "Medial type", 27 cases as "Lateral type" and 10 cases as "Enveloped type" according to arterial morphologies. Besides, 76 cases were identified as "Common type", 15 cases as "Pharynx- invasion type", 18 cases as "Skull base-invasion type" and 20 cases as "Mixed type" according to anatomical relationships. "Enveloped type" of tumors in arterial-relevant classification and "Mixed type" of tumors in anatomical-relevant classification are the most challenging cases for surgeons with the lowest resection rate, highest incidence of carotid arteries injury and postoperative stroke.

CONCLUSION

The modified classifications provide comprehensive understanding of different III-CBTs which are applicable for individualized treatment in clinical practice.

An Anatomic Classification Scheme for Surgical Planning of Renal Artery Aneurysms

PURPOSE

Renal artery aneurysm (RAA) is a rare disease. This study proposed and evaluated a new classification for RAA to assist in surgical decision-making.

MATERIALS AND METHODS

Single-center data of 105 patients with RAAs from the vascular department of vascular surgery were collected retrospectively. A new classification scheme was proposed. Type I aneurysms arise from the main trunk, accessory branch, or first-order branches away from any bifurcation. Type II aneurysms arise from the first bifurcation with narrow necks (defined as dome-to-neck ratio >2) or from intralobular branches. Type III aneurysms with a wide neck arise from the first bifurcation and affect 2 or more branches that cannot be sacrificed without significant infarction of the kidney.

RESULTS

There was 50 (47.62%) type I, 33 (31.43%) type II, and 22 (20.95%) type III aneurysms. The classification assigned endovascular repair as first-line treatment (for type I or II), while open techniques were conducted if anatomically suitable (for type III). A kappa level of 0.752 was achieved by the classification compared with a level of 0.579 from the classic Rundback classification. Technical primary success was achieved in 100% and 96.05%, and symptoms were completely resolved in 100% and 84.85%, while hypertension was relieved in 84.21% and 72.92% of patients receiving open surgery or endovascular repair, respectively. No significant difference was observed for perioperative or long-term complications among the 3 classification types.

CONCLUSION

The new classification proved to be a convenient and effective method for facilitating choice of intervention for RAAs.

CLINICAL IMPACT

This study proposed and evaluated a new classification scheme for renal artery aneurysms, which proved to be a convenient and effective method for facilitating surgical decision-making. Coil embolization was the first-line treatment if suitable, while aneurysm resection and reconstruction with vein graft were conducted for some complex lesions. The safety and efficacy of both open and endovascular methods were validated.

MR imaging-based risk stratification scoring system to predict clinical outcomes in carotid body tumors

Objectives

This study aims to evaluate the role of pretherapy MRI in predicting outcomes in carotid body tumors and propose a grading system for high- and low-risk characteristics.

Materials and methods

A retrospective observational study of 44 patients with 51 lesions was carried out from year 2005 to 2020. MR images were reviewed for characteristics of carotid body tumor, and a score was given that was correlated with intra- and postoperative findings. The various other classifications and our proposed Mahajan classification were compared with Shamblin's classification. The area under the curve and ROC curves were used to present the accuracy of different predictive models.

Results

Our scoring system allotted a score of 0 to 15 on the basis of MRI characteristics, with scores calculated for patients in our study ranging from 0 to 13. Lesions with scores of 0-6 were considered low risk (45%), and scores of 7-15 were regarded as high risk for surgery (55%). The Mahajan classification stages tumors into four grades: I (10%), II (20%), IIIa (8%), and IIIb (62%). The frequency of vascular injury was 50% in category I and 64% in category IIIb. The frequency of cranial nerve injury was 50%, 66%, and 27% in categories I, II, and IIIb.

Conclusion

The Mahajan classification of CBTs evaluates high-risk factors like the distance of the tumor from the skull base and the angle of contact with ICA, which form the major predictors of neurovascular damage and morbidity associated with its surgery. Though the Shamblin classification of CBT is the most widely accepted classification, our proposed Mahajan classification system provides an imaging-based alternative to prognosticate surgical candidates preoperatively.

The value of color doppler ultrasonography combined with computed tomography angiography and magnetic resonance angiography in the preoperative quantification and classification of carotid body tumors: a retrospective analysis

BACKGROUND

Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) provide accurate vascular imaging information, but their use may be contraindicated. Color Doppler ultrasonography (CDU) provides simple, safe, noninvasive, and reproducible imaging. We therefore investigated the role of preoperative CDU combined with CTA and MRA in the quantification, typing, and diagnosis of carotid body tumors (CBTs).

METHODS

We retrospectively analyzed patients with CBTs categorized into group A (type I [n = 1] and type II [n = 10]) or group B (type III [n = 56]) per the intraoperative Shamblin classification. CDU, CTA, and MRA characteristics of CBTs were observed, surgical results were correlated, and the diagnostic threshold of the CBT classification was calculated.

RESULTS

CBTs were usually located at the common carotid artery bifurcation, encircling the carotid artery. An increased angle was found between the internal and external carotid arteries. On CDU, CBTs primarily presented as homogeneous hypoechoic masses with clear boundaries, rich flow signals, and a high-speed, low-resistance artery-like flow spectrum. CTA showed uniform or heterogeneous marked enhancement. MRA showed mixed T1 and slightly longer T2 signals and uniform or uneven obvious enhancement. With increases in the lesion size, amount of blood transfused, and operation time, the intraoperative classification level and possibility of skull-base invasion increased. When the maximum diameter of the lesion, the volume of the tumor, the distance between the upper margin of the tumor to the mastoid and the mandibular angle were 3.10 cm, 10.15 cm3, - 3.26 cm, and 0.57 cm, respectively, the largest Youden index was the best diagnostic boundary value for Shamblin type III tumors.

CONCLUSIONS

CDU combined with CTA and MRA can accurately evaluate the size and classification of CBTs.

Predictors for postoperative cranial nerve complications in carotid body tumor resection: a retrospective cohort study

INTRODUCTION

Carotid body tumors (CBTs) are slow-growing benign tumors. Therefore, surgical resection is considered in case of tumor growth. The timing of surgery is of the utmost importance as the risk of iatrogenic surgical complications increases when resecting larger tumors, whereas on the other hand, resections for asymptomatic small CBT should be prevented. The primary aim of this study was to identify which tumor size or dimension is most accurate to predict nerve injury in patients undergoing resection of a CBT.

MATERIAL AND METHODS

This retrospective cohort study included patients who underwent surgical resection of CBT at the university hospital in South-Holland. Baseline patient characteristics and tumor measurements were retrieved from the medical records. The authors assessed how the different methods of measuring the size of the tumor were interrelated using Pearson correlation. Logistic regression was used to assess which variables were independently associated with nerve injury, including age at surgery, Shamblin classification, and those dimensions that captured different aspects of tumor size (rather than measuring the same as shown by high correlations) as possible independent variables.

RESULTS

In 125 patients, 143 CBTs were resected whereof in 35 cases cranial nerve injury occurred, (transient in 16 cases and permanent in 19 cases). The risks for nerve injury increased with larger tumor size and the Shamblin classification. Logistic regression analysis showed that the anterior-posterior (AP) diameter significantly increased the odds of a nerve injury, a doubling for every 1 cm increase in AP diameter [odds ratio (95% CI) 2.12 (1.29-3.48), P =0.003].

CONCLUSION

This study shows that measured tumor size in the AP plane is a strong predictor for postoperative nerve injury of a CBT resection. This predictor can be used in the daily clinic to give insight in operative risks. More research is needed in order to select the most appropriate time window for CBT resection.

Proteomics analysis of carotid body tumor revealed potential mechanisms and molecular differences among Shamblin classifications

Carotid body tumors (CBTs) are a rare type of paraganglioma, and surgical resection is the only effective treatment. Because of the proximity of CBTs to the carotid artery, jugular vein, and cranial nerve, surgery is extremely difficult, with high risks of hemorrhage and neurovascular injury. The Shamblin classification is used for CBT clinical evaluation; however, molecular mechanisms underlying classification differences remain unclear. This study aimed to investigate pathogenic mechanisms and molecular differences between CBT types. In Shamblin I, II, and III tumors, differentially expressed proteins (DEPs) were identified using direct data-independent acquisition (DIA). DEPs were validated using immunohistochemistry. Proteomics profiling of three Shamblin subtypes differed significantly. Bioinformatics analysis showed that adrenomedullin signaling, protein kinase A signaling, vascular endothelial growth factor (VEGF) signaling, ephrin receptor signaling, gap junction signaling, interleukin (IL)-1 signaling, actin cytoskeleton signaling, endothelin-1 signaling, angiopoietin signaling, peroxisome proliferator-activated receptor (PPAR) signaling, bone morphogenetic protein (BMP) signaling, hypoxia-inducible factor 1-alpha (HIF-1α) signaling, and IL-6 signaling pathways were significantly enriched. Furthermore, 60 DEPs changed significantly with tumor progression. Immunohistochemistry validated several important DEPs, including aldehyde oxidase 1 (AOX1), mediator complex subunit 22 (MED22), carnitine palmitoyltransferase 1A (CPT1A), and heat shock transcription factor 1 (HSF1). To our knowledge, this is the first application of proteomics quantification in CBT. Our results will deepen the understanding of CBT-related pathogenesis and aid in identifying therapeutic targets for CBT treatment.

Preoperative embolization is necessary for large-volume carotid body tumor (≥ 6670 mm3) resection

BACKGROUND

To investigate the impact of preoperative embolization (p-TAE) on CBT surgical resection and explore the optimal tumor volume for p-TAE of CBT resection.

METHODS

This retrospective study reviewed 139 surgically excised CBTs. According to Shamblin classification, tumor volumes, and whether to carry out the p-TAE, the patients were classified into different groups. The demographic, clinical features, and the intraoperative and post-operative information about the patients were retrieved and analyzed from the patient records.

RESULTS

A total of 139 CBTs was excised in 130 patients. According to the results of subgroup analysis, there were no significant differences in surgical time, blood loss, adverse events (AEs), and the revascularization when compared with non-embolization group (NEG) for type I, II, III, respectively (all p > 0.05) except for the surgical time in type I (p < 0.05). Then the X-tile program was employed and determine the cutoff point (tumor volume = 6670 mm3) for tumor volumes and blood loss. The average tumor volume was (29,782.37 vs. 31,345.10 mm3, p = 0.65) for embolization group (EG) and NEG. The mean surgical time (208.86 vs. 264.67 min, p > 0.05) and intraoperative blood loss (252.78 vs. 430.00 mL, p < 0.05) were less, and the incidence of revascularization required (35.56 vs. 52.38%, p > 0.05) and total complications (27.78 vs. 57.14%, p < 0.05) were lower in EG when compared with NEG (tumor volume ≥ 6670 mm3). However, the results were not statistically significant when the tumor size was less than 6670 mm3. No surgery-related mortality was observed during the follow-up.

CONCLUSIONS

Preoperative selective embolization of CBT is an effective and safe adjunct for surgical resection, especially for Shamblin class II and III tumors (≥ 6670 mm3).

The value of ultrasound for the preoperative assessment of carotid body tumors

OBJECTIVES

To evaluate the value of ultrasound (US) examination for the preoperative assessment of carotid body tumors (CBTs) and to predict surgical outcomes.

METHODS

A total of 15 CBT lesions in 15 patients were included in this study. CBT measurements determined using US, and included maximal diameter, volume, tumor distance to base of skull (DTBOS), and carotid wall infiltration. A correlation analysis was conducted to determine the correlation between US measurements and surgical outcomes, including estimated blood loss (EBL), cranial nerve injury, surgical time, and hospital length of stay (HLOS).

RESULTS

EBL showed a high level of correlation with the maximal dimeter (r = 0.596, p < .05) and the volume of the tumor (r = 0.864, p < .05). Surgical time was positively correlated with tumor volume (r = 0.592, p < .05) and negatively correlated with DTBOS (r = -0.554, p < .05). There was no significant correlation (p > .05) shown between cranial nerve injury and US variables. HLOS showed the high degree of correlation with the maximal dimeter (r = 0.658, p < .05), and was also negatively correlated with DTBOS (r = -0.620, p < .00).

CONCLUSIONS

US examination allows for the visualization of features of CBTs, which is a useful and safe tool to be used to predict surgical outcomes. Further research is necessary to validate this exploration method for the preoperative assessment of CBTs.

Comparison of Contrast-Enhanced Ultrasonography to Color Doppler Ultrasound in Evaluation of Carotid Body Tumors

Objective

The objectives of this study were to prospectively 1) explore the characteristics and enhanced patterns of carotid body tumors (CBTs) at color Doppler ultrasound (CDU) and contrast-enhanced ultrasonography (CEUS) qualitatively and quantitatively and 2) compare CDU and CEUS for their morphology and vascularity signature.

Methods

CDU and CEUS with Sonovue^® were used to evaluate 25 CBT lesions. The comparison between these ultrasonic modalities included the size, Shamblin type, vascularity, and feeding vessels of the lesion areas. The time–intensity curve (TIC) analysis was used to obtain the dynamics of the contrast-enhancement features of CBTs.

Results

The TIC analysis presented a fast wash-in [wash-in time: 3.00 ± 1.10 s, mean ± SD] and slow wash-out [wash-out time: 58.79 ± 24.21 s, mean ± SD] pattern in the CBT lesions, with a high area under the curve (AUC) of 669.68 ± 143.46 mm² (mean ± SD). In comparison with CDU, CEUS was superior in identifying Shamblin type I or III CBT lesions (χ² = 17.389, p=0.002). It detected a significant difference in the AUC between moderate and marked vascularity groups (563.33 ± 102.63 vs. 707.22 ± 138.81, t=-2.311, p=0.031.), while CDU observed no significant difference between these two groups. Although CDU was more sensitive than CEUS in detecting feeding vessels (100% vs. 88%), CEUS better visualized the origins of feeding vessels (χ² = 9.162, p=0.010).

Conclusion

CEUS can better investigate the Shamblin type and vascularity of CBT lesions than CDU. CBTs displayed a fast wash-in, slow wash-out pattern with high AUC in the TIC analysis in the CEUS mode. CDU is more sensitive in detecting feeding vessels than CEUS, while CEUS can better visualize the origins of feeding vessels.

Local Tumor Behavior Associated With Survival Among Patients With Paraganglioma of the Head and Neck

Objective

The purpose of this study was to evaluate the utility of ICD-O-3–classified local tumor behavior as a prognosticator of head and neck paraganglioma (HNP) outcomes.

Study Design

Retrospective cohort study.

Setting

National Cancer Database between 2004 and 2016.

Methods

This study included patients aged ≥18 years who were diagnosed with HNP. Clinical outcomes and clinicopathologic features were compared with regard to local tumor behavior.

Results

Our study included 525 patients, of which the majority had HNP classified as locally invasive (45.9%) or borderline (37.9%). The most common anatomic sites involved were the carotid body (33.7%), intracranial regions (29.0%), or cranial nerves (25.5%). Carotid body tumors were exclusively locally invasive, whereas intracranial and cranial nerve HNP were overwhelmingly benign or borderline (94% and 91%, respectively). One-fourth of patients underwent pathologic analysis of regional lymph nodes, of which the majority were positive for metastasis (80.6%). Metastasis to distant organs was twice as common in patients with locally invasive tumors vs benign (15% vs 7.1). For benign disease, surgery with radiotherapy (adjusted hazard ratio [aHR], 40.45; P = .006) and active surveillance (aHR, 24.23; P = .008) were associated with worse survival when compared with surgery alone. For locally invasive tumors, greater age (aHR, 1.07; P < .0001) and positive surgical margins (aHR, 4.13; P = .010) were predictors of worse survival, while combined surgery and radiotherapy were predictors of improved survival vs surgery alone (aHR, 0.31; P = .027).

Conclusion

While criteria for tumor behavior could not be defined, our results suggest that such a classification system could be used to enhance HNP risk stratification and guide clinical management decisions.