Prognostic's Factors of Head and Neck Paragangliomas Evolution

Cervical paragangliomas (HNPG) are rare tumors (0.6% of head and neck tumors) arising from chromaffin tissue, of cervical paraganglia (PGL). The most common locations are carotid body (60% of cases), jugulo-tympanic region and vagal body.

More than 30% are proved to occur in a context of genetic predisposition, more often in young people, and genetic screening is recommended in all patients. Multifocal tumors represent 12% of all HNPG and until 50% of familial forms. Most of HNPG are non-secreting, benign and slow growing tumors, but up to 30% present complications of local growth, and up to 10% can develop distant metastasis that define malignancy since there is no pathological marker.

Historically, surgical treatment was the standard of care but represents nowadays around 50% of the treatment, mostly due to the identification of high morbidity rates. The rate of recurrence is probably around 10% at 5 years. Radiotherapy and active follow-up represent the main therapeutic alternatives.

The standard of care is classically surgical but may expose to important sequelae leading to a review of its primary indication. Indeed, cranial nerve palsies (VII, IX, X, XI and XII) may complicate up to 20% of carotid PGL surgeries and up to 95% of vagal PGL surgeries. They are leading to significant functional sequelae, sometimes requiring recourse to a gastrostomy (4/79 patients operated on in a retrospective cohort). First bite syndrome, Claude Bernard Horner syndrome, baroreceptor failure, xerostomia, and ischemic events complicate 5.8%, 4.9%, 1.9%, 1%, and 1% of surgeries respectively. In a local retrospective study conducted by the Hospices Civils de Lyon on 34 operated cervical PGL, the overall complication rate reached 62%. These complications depend mainly on the location tumor and its size.

Control rate of irradiated HNPG at 5 years from retrospective series seems to be around 90%. They seems also to have a possible better progression-free survival at 15 years than surgery. The tolerance is correct, the risk of induced malignancy is estimed at 1/1000 to 1/2000. Without treatment, 44% of cervical PGL show a significant progression (median follow-up 51 months). Progression is estimated at 0.41 mm/year for jugulo-tympanic PGL and 1.6 mm/year for vagal and carotid PGL.

Currently, there is no clear and robust consensus regarding the follow-up of cervical PGL and the indications for different therapeutic strategies. Data available are represented by retrospective studies only, mostly small in size, with heterogeneous and often inadequate follow-up compared to slow tumor growth.

Thus, this prospective cohort study with a standardized long-term follow-up will allow to characterize the management modalities and the evolution of this population.