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

BACKGROUND: 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 1 December 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 9,291 patients and 9,862 tumors were identified. The pooled results indicated that the median age of CBT patients 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%. 16% patients experienced multiple paragangliomas and 12% 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 to non-PE, PE reduced the estimated blood loss (EBL) (standardized mean difference [SMD] -0.95; 95% confidence interval [CI] -1.70, -0.20) and the operation time (SMD -0.56; 95% CI -1.03, -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. SDH gene mutation-positive patients 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 EBL and operation time. Higher Shamblin grade tumors increased the incidence of operative complications. SDH gene mutation-positive patients had the most relevant family histories and symptoms.