Radiotherapy in glomus tumours (paragangliomas). A 25 year-review

Radiation-Induced Malignant Peripheral Nerve Sheath Tumor of the Vagus Nerve Following Radiation Treatment of Cervical Paraganglioma

Radiation-induced sarcoma is a known but rare complication of radiation treatment for skull base paraganglioma. We present the cases of a female patient with multiple paraganglioma syndrome treated with external beam radiation treatment who presented 4 years later with a malignant peripheral nerve sheath tumor of the vagus nerve.

The management of head-and-neck paragangliomas

Paragangliomas (PGLs) are tumours originating from neural crest-derived cells situated in the region of the autonomic nervous system ganglia. Head-and-neck PGLs (HNPGLs) originate from the sympathetic and parasympathetic paraganglia, most frequently from the carotid bodies and jugular, tympanic and vagal paraganglia, and are usually non-catecholamine secreting. Familial PGLs are considered to be rare, but recently genetic syndromes including multiple PGLs and/or phaeochromocytomas have been more thoroughly characterised. Nowadays, genetic screening for the genes frequently implicated in both familial and sporadic cases is routinely being recommended. HNPGLs are mostly benign, generally slow-growing tumours. Continuous growth leads to the involvement of adjacent neurovascular structures with increased morbidity rates and treatment-related complications. Optimal management mostly depends on tumour location, local involvement of neurovascular structures, estimated malignancy risk, patient age and general health. Surgery is the only treatment option offering the chance of cure but with significant morbidity rates, so a more conservative approach is usually considered, especially in the more difficult cases. Radiotherapy (fractionated or stereotactic radiosurgery) leads to tumour growth arrest and symptomatic improvement in the short term in many cases, but the long-term consequences are unclear. Early detection is essential in order to increase the chance of cure with a lower morbidity rate. The constant improvement in diagnostic imaging, surgical and radiation techniques has led to a safer management of these tumours, but there are still many therapeutic challenges, and no treatment algorithm has been agreed upon until now. The management of HNPGLs requires a multidisciplinary effort addressing the genetic, surgical, radiotherapeutic, oncological, neurological and endocrinological implications. Further progress in the understanding of their pathogenesis will lead to more effective screening and earlier diagnosis, both critical to successful treatment.

Carotid body paragangliomas: a systematic study on management with surgery and radiotherapy

The definitive universally accepted treatment for carotid body tumors (CBT) is surgery. The impact of surgery on cranial nerves and the carotid artery has often been underestimated. Alternatively, a few CBTs have been followed without treatment or irradiation. The goal of this study is to summarize the existing evidence concerning the efficacy and safety of surgery and external beam radiotherapy (EBRT) for CBT. Relevant articles were identified using strict criteria for systematic searches. Sixty-seven articles met the criteria which included 2,175 surgically treated patients. On the other hand, 17 articles including 127 patients treated with EBRT were found. Long-term control of the disease was obtained in 93.8% of patients who received surgical treatment and in 94.5% of the radiotherapy group. Surgery resulted in 483 (483/2,175 = 22.2%) new cranial nerve permanent deficits, whereas in the EBRT group, no new deficits were recorded (p = 0.004). The common/internal carotid artery was resected in 271 (12.5%) patients because of injury or tumor encasement, with immediate reconstruction in 212 (9.7%) patients. Three percent (60) of patients developed a permanent stroke and 1.3% (26) died due to postoperative complications. The major complications rates and the mortality after completion of the treatment also were significantly higher in surgical series compared to EBRT series. This systematic analysis highlights evidence that EBRT offers a similar chance of tumor control with lower risk of morbidity as compared to surgery in patients with CBT. This questions the traditional notion that surgery should be the mainstay of treatment.

Long-term results of surgery for temporal bone paraganglioma

The only way to resolve the dispute about the effectiveness of surgery versus radiation therapy for glomus tympanicum and jugulare tumors is adequate long-term studies. In a retrospective study with an average follow-up period of 15 years (range 11 to 23 years) we reassessed 11 patients with glomus tympanicum tumors and 11 patients with glomus jugulare tumors. Ten of 11 patients with glomus tympanicum tumor were tumor-free after surgery. A temporary facial palsy and an external meatal wall defect were the only surgical complications. The air-bone gap postoperatively closed to within 10 dB in three patients, to within 20 dB in six patients, and to more than 30 dB in one patient. Nine of 10 patients with glomus jugulare tumor receiving complete resection were tumor-free. Less than half the patients experienced new-onset cranial nerve function loss, and all made satisfactory recovery, eliminating the need for tracheostomy or gastrostomy. In two patients, the hearing could be preserved on the preoperative level, but the majority already presented with deafness. In the long-term, surgery remains a treatment of choice for glomus tympanicum tumors. It is also an extremely effective treatment with low morbidity for glomus jugulare tumors, including those with intracranial extension.

Definitive radiotherapy in the management of paragangliomas arising in the head and neck: a 35-year experience

BACKGROUND

An evaluation of the treatment results for 104 patients with 121 paragangliomas of the temporal bone, carotid body, and/or glomus vagale who were treated with radiation therapy (RT) at the University of Florida between 1968 and 2004.

METHODS

Eighty-nine paragangliomas (86%) were treated with conventional megavoltage techniques, 15 (14%) patients with stereotactic fractionated radiation therapy, 6 (6%) patients with stereotactic radiosurgery (SRS), and 11 (11%) patients with intensity-modulated radiation therapy (IMRT).

RESULTS

There were 6 local recurrences. One recurrence was salvaged with additional RT. The actuarial local control and cause-specific survival rates at 10 years were 94% and 95%. The overall local control rate for all 121 lesions was 95%; the ultimate local control rate was 96%. The incidence of treatment-related complications was low.

CONCLUSION

Fractionated RT offers a high probability of tumor control with minimal risks for patients with paragangliomas of the temporal bone and neck.

Radiation therapy, an important mode of treatment for head and neck chemodectomas

Between 1970 and 1990, 22 patients with 44 chemodectomas in the head and neck region were seen at the Netherlands Cancer Institute in Amsterdam. All patients were treated with radiation therapy (17 patients with radiation therapy only and 5 in combination with surgery). One patient was treated two times with an interval of 12 years at each side of the neck. Standard dose was 50 Gy in 25 fractions over 5 weeks. A radiation portal arrangement with oblique fields with paired wedges was used most frequently. The follow-up period ranged from 1 year to 20 years. Two recurrences at 2 and 9 years after treatment were observed. The actuarial local control rate was 88% at 10 years follow-up. Comparison of the results of surgery and radiotherapy demonstrates that radiation therapy is an effective treatment modality without mutilation or severe late morbidity for chemodectomas in the head and neck region.