Neuro-oncology

Brain metastases

Glioma Grade 4 > Grade 3 > Grade 2

Pituitary tumours

Ependymomas

Lymphoma

P.N.E.T. (Primitive neuro ectodermal tumour)

Pineal Tumours inc germ cell tumours

Atypical Meningiomas

Primary spinal tumours

Pituitary Irradiation

Questions

What are the indications for radiotherapy ?

What does conventional radiotherapy involve?

Radiosurgery ?

What is stereotactic linear accelerator based radiotherapy ?

Indications for Pituitary Irradiation

Suprasellar extension

Cavernous sinus involvement

Recurrent Disease

Uncontrolled endocrinopathy

Medically unfit

Suprasellar Extension

Pre op Post op

Cavernous sinus involvement

Recurrent Disease

Uncontrolled Endocrine Effects

Results

Results

90% control of Pituitary tumour at 10 years following surgery and radiotherapy

Visible tumour Gross Tumour Volume (GTV)

GTV plus Normal tissue containing microscopic disease Clinical Target Volume (CTV)

CTV plus Further tissue to allow for organ movement, set up Planning Target Volume (PTV)

Radiotherapy Planning

Suprasellar Extension

Pre op Post op

Conventional Radiotherapy

Standard immobilisation shell

CT planning scan

Fractionated treatment (25 usually)

Conventional Radiotherapy

Intention is to reduce the set up margin by more rigid immobilisation and conforming beams.

Field size restricted to smaller fields

Main indication when the subclinical invasion is minmalBenign, AVM, or only treating GTV

Stereotactic Radiotherapy

Stereotactic Radiotherapy

Precise positioning in three-dimensional space.

In stereotactic surgery, a system of three-dimensional coordinates is used to locate the site to be operated on.

In stereotactic radiotherapy, a system of three-dimensional coordinates is used to locate the site to be irradiated bya number of precisely aimed beams of ionizing radiation from diverse directions meeting at a specific point.

Stereotactic Radiotherapy

Leksell Unit

Stereotactic Radiosurgery

Leksell Unit

Stereotactic Radiosurgery

Single fraction

Ablative dose

Use for lesions where there is no significant subclinical spread.

Small fields 4cm or less

Immobilisation imperative

Examples AVMAcoustic neuromasMeningiomasMetastases

Stereotactic Radiosurgery

Linac based system

Stereotactic Radiosurgery Stereotactic Radiotherapy

Multiple conventional fractions exploits reduced patient movement to reduce morbidity

Use for lesions where there is minimal subclinical spread or as a boost to GTV only

Immobilisation device must allow for repositioning daily

Examples Pituitary tumoursMeningiomasGliomas (needs further studies)

Stereotactic Linear accelerator based Radiotherapy

Conventional Radiotherapy Plan unavoidable dose to normal structures outside target volume

Intensity Modulated Radiotherapy (I.M.R.T.)

Multiple beams, non uniform dose across the beam

Intensity Modulated Radiotherapy (I.M.R.T.)

Radiotherapy Side Effects

During Tired, Hair loss, tumour swell

2 months Somnolence, Recurrent symptoms: recurrence, necrosis or tumour swell

6 months Late radiation necrosis

2 years Intellectual deterioration

Radiotherapy side effectsLate Damage up to 10 years +

• Thickening of endothelial lining

• Hypoxia

• Necrosis.

Loss of functionLoss of functionEg. Brain necrosis, Eg. Brain necrosis, Brachial plexopathy following breast cancer treatmentBrachial plexopathy following breast cancer treatment

Late EffectsTumourigenesis

Some studies find patients who have had standard pituitary radiation therapy are at a 9.4- to 16-fold increased risk for malignant brain tumours (such as astrocytomas or gliomas) in comparison with the risk in the general population.

Pituitary Irradiation

Summary

Indications

Conventional vs more technical radiotherapy

Side effects usually rare and manageable