Brain Metastases

Robert Miller MDwww.aboutcancer.com

Brain metastases or primary brain tumors (glioma)

Treatment options Side effects of treatment

Brain metastases: cancer that started elsewhere in the body (e.g. lung or breast) and spread to the brain

Brain primary: a normal brain cell (glial cell) becomes malignant and is called a glioma

Brain Metastases

Most common intracranial tumors in adults

In patients with stage IV disease , 10 – 30% will have brain mets

The odds of developing brain metastases based on the primary type of cancer

Lung: 16 to 20%

Melanoma: 7% Kidney: 7 to 10% Breast: 5% Colorectal: 1 to 2%

The most common causes of brain metastases in adults with their approximate frequency are:

    Lung — 50 percent    Breast — 15 to 20 percent    Unknown primary 10 percent    Melanoma — 10 percent    Colon and rectum 5 percent

The distribution of metastases roughly follows the relative weight of and blood flow to each area.

    Cerebral hemispheres — 80 percent    Cerebellum — 15 percent    Brain stem — 5 percent

SYMPTOMS OF BRAIN METASTASES

Symptom Patients %

Headache 42 Focal weakness 27 Mental change 31 Seizure 20 Gait ataxia 17 Sensory disturbance 6 Speech problems 10

Note that tumors may cause symptoms on the opposite side of the body

Brain Swelling – brain tumor often cause swelling or edema which creates pressure on the brain, with headaches and nausea, steroids like Decadron (dexamethasone) will decrease this pressure

Brain Imaging

Glioblastoma

Certain brain tumors .e.g. glioma have a distinct appearance on MRI scan . With irregular borders and necrotic center

Glioblastoma cells in green, spread diffusely through the brain and are hard to target accurately

Brain Metastasis as seen on an MRI Scan, the sharp margins may make this a better case for highly targeted radiation

Normally the radiologist can tell the difference between a brain tumor and a stroke (if not sometimes a biopsy is necessary)

Other Brain Tumors that are NOT cancer

Both of these are examples of a brain abscess

Multiple Brain Metastases

MRI suggests that in 66 to 75% of the cases, there are multiple metastases

Metastases from breast, colon, and renal cell carcinoma are more often single,

while lung cancer and malignant melanoma have a greater tendency to produce multiple metastases

Brain Metastases are usually Multiple (66 – 75% of the cases)

Brain Metastases are Usually Multiple

PET Scans and the BrainBecause a PET measures uptake of glucose and the brain uses a lot of glucose, the normal brain looks very active on a PET scan

PET Scans and the Brain

PET scan showed an abnormal area in the left frontal lobe and MRI confirmed this as a brain metastasis from breast cancer

Brain Radiation

Depending on the type and number of brain tumors, the patient may receive radiation to the whole brain, or partial brain or have highly targeted radiation (called radiosurgery, e.g. Cyberknife or gamma knife)

www.nccn.org

Whole brain irradiation

Whole brain radiation

The response or benefit from whole brain radiation may take several weeks to months

Typical Response to Whole Brain Radiation

The small lesion is no longer visible and the large lesion is much smaller

Typical response for whole brain radiation

Typical response for whole brain radiation, small cell lung cancer

Typical response for whole brain radiation

Radio resistant cancer (renal cell) MRI appearance two months after whole brain radiation (small lesions gone and large lesion much

smaller)

Radiosurgery for Cancer

Typical time interval to regression after radiosurgery Cyberknife or Gamma Knife)

For a single lesion, radiosurgery alone may be used, but there is a higher risk of a new lesion showing up in the brain

Jan 2011 - Radiosurgery Aug 2012 – Treated tumor is virtually gone, but there is a new tumor on the opposite side of the brain

Radiation Doses

Whole brain: 20 – 40 Gy in 5 to 20 fractions

Radiosurgery: 15Gy (3.1 – 4cm), 18Gy (2.1 to 3cm) or 24Gy (2cm or less)

How often does whole brain radiation help?

• 70 -90% initial response • > 50% of symptoms of headache, CSF pressure have complete response • 50 -60% have functional improvement

moderate dysfunction: 1/3 near normal at median time of 3 weeks severe dysfunction: 2/3 improve at median of 1-2 weeks

Side Effects of Whole Brain Radiation

1. Hair loss (usually takes two or three weeks to happen)

2. Mild skin itching or irritation

3. Short term more fatigue or slightly more confusion or memory problems

4. Mild headache or nausea is uncommon but may require medication (Decadron)

5. Occasionally hearing problems (fluid behind the ear drums)

Long Term Effects of Radiation on the Brain

This patient had no symptoms, but radiation may effect memory

Long Term Effects of Radiation on the Brain

This patient had no symptoms

Long Term Effects of Radiation on the Brain

This patient had no symptoms

Long Term Effects of Radiation on the Brain

This patient had no symptoms

Risk of white matter changes (leukoencephalopathy) 1 year after whole brain radiation for brain mets

U Pitt Study E Monaco (AANS 2012, Medscape Med News 2012-05-01)

WB+SRS SRS

1 year 97.3% 3.2%

So by one year 97% has some changes and by 2 years 70% had grade 3 changes on the MRI (but no symptoms)

Radiosurgery for Brain Metastasis

Local control Rates of 73 to 94% Risk of radiation necrosis of 5 to 10%

Better than whole brain if single lesion and good performance patient in the RTOG 95-08 Trial

Complications of Radiosurgery

Short term side effects are uncommon (2%) with worsening symptoms or new seizures

About one third mild swelling (headaches, nausea)

Radionecrosis in 5% to 10%

Sometimes the MRI will look worse after radiosurgery due to radionecrosis of the cancer but with time this should fade away

Survival and Prognosis for People with Brain Metastases

1. Do best if the cancer is confined to the brain only2. Do better if they are young (< 65y)3. Do better if they have a good performance score (i.e. a

high Karnofsky score of 70 or better)

Karnofsky Score (KPS) 70 = Cares for self; unable to carry on normal activity or do active work KPS 60 = Requires occasional assistance, but is able to care for most personal needs

Median Survival Based on RTOG Class for People with Brain Metastases

I (KPS =70, age < 65y, mets to brain only) = 7.1 to 10.5 months

II KPS = 70 = 3.5 to 4.2 months III KPS < 70 = 2.0 to 2.3 months

Karnofsky Score (KPS) 70 = Cares for self; unable to carry on normal activity or do active work KPS 60 = Requires occasional assistance, but is able to care for most personal needs

Survival by Treatment (WB whole brain, S surgery, RS radiosurgery) and Performance

Score (RTOG)

RTOG WB S RS

I 7.1 mos 14.8 mos 16.1 mos

II 4.2 mos 9.9 mos 10.3 mos

III 2.3 mos 6.0 mos 8.9 mos

Brain Metastases

Robert Miller MDwww.aboutcancer.com