Late term complications after radiotherapy of the neck; Cognitive functioning and gait.

Radiation induced carotid vasculopathy with subsequent increased risk of
cerebrovascular accidents is a well known late complication of Radiotherapy
(RT) of the neck. More knowledge of the underlying pathofysiology is needed to
develop prevention strategies and to identify patients at risk. We have an
unique prospective cohort of patients treated for head and neck malignancies
with prior irradiation of the neck. Baseline and 2 years after RT Intima Media
Thickness (IMT) measurements of both carotid arteries are performed. We will
expand the follow up period of this cohort to 5 years after RT to answer the
following questions.

The first question to be answered is what is the relation between RT and
imaging characteristics of atherosclerosis? The hypothesis is that irradiation
induces premature atherosclerosis. It is unclear whether the location and
composition of these postirradiation vessel wall changes are different from
those in more common atherosclerosis due to cardiovascular risk factors. With
advanced imaging techniques we will assess the extra- and intracranial
arteries in all patients.

The second question to be answered is what is the relation between RT and
asymptomatic cerebral vascular changes? It is known that the prevalence of
silent brain infarcts is up to fivefold higher than the prevalence of stroke in
the community. These changes have a major impact on cognitive functioning and
gaith and balance disorders. Carotid artery pathology increases this risk. To
assess this, all the study patients will undergo MRI of the brain to score
white matter lesions, silent brain infarcts and cerebral atrophy.

The third question to be answered is what is the relation between RT and
symptomatic vascular events? When carotid or cerebral arteries are within the
RT field, there is an increased risk to develop cerebrovascular accidents.
Within the first 2 years after RT of the neck, we found a 8 times higher
incidence of stroke and a 16 times higher incidence of TIA, when compared to
the community. Cerebrovascular risk factors and vascular diseases will be
assessed in all patients.

The fourth question to be answered is what is the relation between RT induced
cerebral vascular lesions and gaith disturbances? To assess this we will
perform quantitative gaith analysis in all patients.

The fifth question to be answered is what is the relation between RT and
cognitive functioning? We know that silent brain infarcts in the community are
associated with worse cognitive ability and increased risk of developing
dementia. Therefore, we will perform neuropsychological tests in all the study
participants.

To study late term complications after radiotherapy of the neck

Design: Prospective cohort study

All patients had already baseline (before RT) and 2 years after RT follow-up.
At every visit they underwent a structured interview, neurological
excamination, laboratory investigatuin ans duplex ultrasonography.

At the 6 year follow-up patient will undergo:
- Structured interview and neuroloical excamination, including ECG
- Fasting laboratory investigation (glucoses, cholesterol)
- MRI/A of brain and extra- and intracranial arteries
- Duplex Ultrasonography of carotid arteries (IMT, strain imaging)
- Gaith analysis
- Neuropsychological Excamination and questionaries (HADS, CIS)

When clinincal relevant abnormalities are found on the laboratory
investigation, ECG, duplex ultrasonography or MRI/A, the studycoordinator will
inform the patient and the general practicioner. All MRI/A's will be officially
asessed by a neuro-radiologist.