Improving Outcomes in Carotid Body Tumors Treatment: The Impact of a Multidisciplinary Team Approach

Succinate dehydrogenase mutations in head and neck paragangliomas: A systematic review and meta-analysis of individual patients' data

BACKGROUND

Head and neck paragangliomas (HNPs) have been associated with gene mutations in the succinate dehydrogenase (SDH) complex, but the clinical significance remains unclear. We sought to explore the demographics, clinical characteristics, treatment methods, and outcomes of SDH-mutated HNPs.

METHODS

Databases were systematically searched. Pooled event ratio and relative 95% confidence intervals were calculated for dichotomous outcomes. Meta-regression was performed. Cochran's Q test and I2 test assessed heterogeneity. Funnel plot and Egger's regression test assessed publication bias.

RESULTS

Forty-two studies with 8849 patients were included. Meta-regression revealed a significant correlation between multifocality and SDHD mutations (0.03 ± 0.006, p < 0.0001) and between distant metastases and SDHB mutations (0.06 ± 0.023, p = 0.008). There was no correlation between sex, age, tumor size, or familial occurrences and SDH-related mutations.

CONCLUSION

Multifocality of HNPs correlates with the SDHD mutational subtype, and metastases correlate with the SDHB subtype. Knowledge of HNP phenotypes associated with SDH-related mutations has the potential to influence the management approach to such HNPs.

Current management of carotid body tumors

Carotid body tumors (CBTs) are neoplasms that occur at the bifurcation of the carotid artery and are pathologically classified as paragangliomas. In the 4th edition of the WHO classification, paragangliomas are categorized as neoplasms with malignant potential. Clinically, about 5% of CBTs present with malignant features such as metastasis. Currently, it is challenging to distinguish between tumors with benign courses and those that present malignantly. Recent advances in genetic testing have elucidated the genetic characteristics of paragangliomas, including carotid body tumors. Over 20 genes have been identified as being involved in tumor development. Particularly in head and neck paragangliomas, abnormalities in genes related to succinate dehydrogenase are frequently observed. Research is ongoing to understand the mechanisms by which these genes contribute to tumor development. The definitive treatment for CBTs is surgical resection. These tumors are prone to bleeding and often adhere firmly to the carotid artery, making intraoperative bleeding control challenging. The risk of lower cranial nerve paralysis is relatively high, and there is a risk of stroke because of manipulation of the carotid artery. Preoperative evaluation with angiography is essential, and a multi-disciplinary surgical team approach is necessary. In cases where the tumor is difficult to resect or has metastasized, radiation therapy or chemotherapy are employed. Clinical trials involving targeted molecular therapies and radiopharmaceuticals have recently been conducted, with some applied clinically. The development of various new treatments is anticipated, providing hope for therapeutic options in refractory cases.

Retrocarotid dissection technique compared to the caudocranial approach for the surgical treatment of carotid body tumors: A 15-year experience

INTRODUCTION

Carotid body tumors are rare neoplasms with malignant potential. We aim to follow up on our initial experience published in 2015 and compare the occurrence of complications and postoperative outcomes with the use of retrocarotid dissection (RCD) against the standard caudocranial (SCCD) technique.

METHODS

This was an observational, case-control study in which we analyzed all of the carotid body tumor resections performed from 1986 to 2022. Parametric and nonparametric tests were used accordingly. Statistical analysis was performed on Stata 17.

RESULTS

A total of 181 surgical procedures were included, mean age was 56 years (± 13.63), and 168 (93%) were performed in women. The mean medio-lateral diameter was larger in the RCD group (2.85 ± 1.57 cm vs 1.93 ±1.85 cm; p = 0.002) and presurgical embolization was more frequently performed in the SCCD group (27.5% vs 0.7%; p < 0.001). A total of 40 (22.09%) resections were performed using the SCCD technique. In contrast, in 141 (77.91%) procedures the RCD technique was used. The mean surgical time in the RCD group was lower (197.37 ± 70.56 min vs 232 ± 98.34 min; p = 0.01). No statistically significant difference was found between SCCD and RCD in terms of vascular lesions (n = 20 [11.04%], 15% vs 9%, respectively; p = 0.36), transient or permanent nerve injuries (25% vs 33%, respectively; p = 0.31), or mean intraoperative bleeding (SCCD: 689.95 ± 680.05 mL vs RCD: 619.64 ± 837.94 mL; p > 0.05).

CONCLUSIONS

RCD appears to be a safe and equivalent alternative to the standard caudocranial approach in terms of intraoperative bleeding or vascular lesions, with a sustained, significant decrease in surgical time.

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.

Five-year outcome of a staged giant Shamblin type III carotid body tumor excision

Giant carotid body tumors, defined as those >8 cm in size, are extremely rare. Definitive surgical management is a complex undertaking because these large tumors tend to have grown to envelop cranial nerves and the carotid artery, and few data exist regarding the long-term outcomes for these patients. We present the case of a patient with bilateral giant carotid body tumors who underwent staged embolization and excision of a >10-cm carotid body tumor. After 5 years of follow-up, we demonstrated that elective open repair can provide long-term symptomatic relief. We describe and illustrate the crucial steps and considerations regarding the excision of complex Shamblin type III carotid body tumors.