Survival from Carotid Body Tumors
Surgical Resection of Carotid Body Tumors: Long Term Survival, Recurrence, and Metastasis, Nora, Mayo Clinic Proceedings 63:348 (1988)
These authors performed a retrospective review of surgical procedures between 1965 and 1985. They identified 55 patients with 59 carotid body tumors who had undergone surgical procedures. Complete follow-up was available for all 55 patients. (medium duration of follow-up, 10 years). Six patients (11%) experienced a preoperative cranial nerve dysfunction involving the vagus nerve, the hypoglossal nerve, the glossal pharyngeal nerve, or the mandibular branch of the facial nerve. Mean duration of time between patient’s discovery of a neck mass and excision was 86 months (7.2 years)(range 0-46 years).
The difficulty of excision of the tumors was graded by the method of Shamblin and Associates. Group I tumors are well localized and easily resected. Group II tumors adhere to and partially surround carotid vessels. Group III tumors surround carotid arteries.
Of the 35% of patients had headache, pain preoperative symptoms; 13% had dizziness; 8% had dysphagia; 8% had voice change.
They determine the size of the tumors by assuming that each tumor approximated a sphere and by calculating its volume from the measurements of the surgical specimens using the formula: X x Y x Z x .5236 = cm³, in which X is the length, Y is the width and Z is the depth. The tumors ranged in size from 2 cm³ to 164 cm³. The medium size was 7 cm³ in Group I, 11 cm³ in Group II, and 22 cm³ in Group III. A significant association was noted between larger size and increasing difficulty of excision of the tumor. They also found an association between larger size of the tumor and increased duration of presence in the neck mass.
Five of the 52 patients who underwent complete surgical excision (10%) had a central neurologic deficit perioperatively. All the neurologic deficits occurred in patients who had carotid artery repair at the time of the initial excision. No internal carotid arteries were ligated in this series of patients. One of the neurologic deficits was temporary, one caused a perioperative death, and three were permanent.
Eleven patients (21%) experienced permanent dysfunction of a cranial nerve, most commonly the vagus nerve. These patients had various complaints depending on the cranial nerve dysfunction: dysphagia, hoarseness, difficulty chewing, or choking easily on food. A significant incidence of cranial nerve dysfunction was associated with increased difficulty of tumor excision and increased tumor size.
One patient (2%) who had no evidence of metastatic disease at the time of the original operation devolved at 7 years after the total excision. Initially, she had bony metastasis. Two years later she died from one metastasis. Three patients (6%) had recurrence after having undergone complete excision.
Current techniques allow safe, complete excision of carotid body tumors with minimal associated mortality and a decreasing incidence of central nervous system dysfunction, as evidenced by one death and the occurrence of only one CVA during the past ten years. Cranial nerve morbidity has remained high. A partial explanation for this is that some patients already have involvement of the cranial nerve at the time of initial examination. Post-operative cranial nerve dysfunction according to the literature affects 20-40% of patients, but about 50% of these cranial nerve injuries are temporary. The authors found a significant increase in cranial nerve dysfunction in association with larger tumors. Thus, the best means of minimizing cranial nerve dysfunction is early resection of tumors when they are small (Shamblin Group I or II).
These tumors are capable of metastatic growth. They have been reported to metastasize to bone, lung, lymph nodes, liver, kidney, pancreas, thyroid gland and heart. Local involvement of carotid vessels, nerves and the base of the skull have also been observed. Some claim that histologic criteria correlates with malignant potential. Others disagree. They believe that the true proof of malignancy is the presence of lymph node or distant metastasis which may not become evident for many years after the original resection. Some researchers suggest that all be considered malignant because of their progressive involvement of local neurovascular structures. Younger patients with carotid body tumors have an increased risk for development of malignant tumors. Martin reported that the mean age of patients with malignant tumors was 32 years in comparison of mean age of 47 in those with benign disease. These tumors, if left untreated, will encompass the carotid arteries and adjacent nerves. As the difficulty of excision increases, the patient is at increasing risk for neurovascular complications. Unchecked local growth can result in a poor quality of life as reported in several series. These tumors have malignant potential especially in the young population.