PNNI.ORG Website

METASTATIC BRAIN TUMORS

David Black PA-C

Oct.10, 2003

Cerebral mets are the most common brain tumor seen clinically, comprising slightly more than half of all brain tumors.

In the U.S., the annual incidence of new cases of cerebral mets is >100,000, compared to 17,000 for primary tumors.

15-30% of cancer patients develop cerebral mets.

15% of patients who present with cerebral mets & unknown primary

43-60% have an abnormal chest x-ray.

Mets occur in only 6% of pediatric cancers

Solitary mets

At the time of diagnosis, 50% are solitary on CT

If the above patients have an MRI, >70% will have multiple lesions

Increasing Incidents of Mets

	Increased length of survival in cancer patients
	greater ability to diagnose CNS tumors
	Many chemo drugs do not cross BBB
	Newer chemo drugs may weaken the BBB

Primary CA�s

Lung 44%

Breast 10%

Kidney (Renal Cell) 7%

GI 6%

Melanoma 3%

Undetermined 10%

Location

80% are located in the cerebral hemispheres

Trigone most common site (MCA terminus)

Grey/white junction

16% occur in cerebellum

mets are the most common posterior fossa tumor in adults

Presentation

68% - Progressive Neurological Deficit

45% - Motor Weakness

54% - Headache

26% - Seizures

Workup

metastatic workup

	a. done prior to obtain tissue biopsy
	b. CXR, CT chest, abd, & pelvis
	c. Heme test stool
	d. Bone scan
	e. Mammogram

Management

11% of patients with abnormalities on CT or MRI and with a history of CA (within the past 5 yrs) do not have cerebral mets.

Medical Management

a. Dilantin � for mid-brain or large tumors

b. Steroids

	i. Many symptoms are due to tumor vasogenic edema.
	ii. Should respond to steroids within 24-48 hrs.
	iii. Improvement is not permanent

c. H2 Blocker

Chemotherapy

	a.. BBB effectively excludes many chemotherapeutic agents from the brain
	b. In mets, the brain may serve as a "safe haven".
	c. Intrathecal and direct contact chemo agents are being developed, but no yet promising

Radiation

a. Steroids and radiation usually help head ache symptoms, and resolve symptoms in 50% of patients

b. With usual dose (30Gy in 10 divided doses over 2 wks), 11% at 1 year and 50% at two year survivors develop severe dementia

c. Radio-resistant tumors

d. Large Cell Carcinoma

	i. Melanoma
	ii. Renal Cell

e. Radio-sensitive Tumors

	i. Small cell Lung Carcinoma
	ii. Germ Cell Tumors
	iii. Lymphoma
	iv. Leukemia
	v. Multiple Myeloma

f. Prophylactic WBR

i. WBRT after resection of a SCCL reduces cerebral relapses, but does not affect overall survival.

Post-Op Radiation

a. WBRT is has traditionally been administered following surgery, especially with SCCL where "micro-metastasis" are presumed

Surgical Management

a. Solitary Lesions

i. Indications favoring surgical excision

1. Primary Disease controlled

2. Lesion accessible

3. lesion is symptomatic or life-threatening

4. primary tumor known to be radio-resistant

5. primary unknown

a. Multiple Lesions

ii. Usually treated with XRT

iii. If total surgical resection of all mets is possible, then survival is comparable with solitary met.

iv. Indications for surgical excision of multiple mets

1. one particular and accessible lesion is clearly symptomatic and/or life threatening (including posterior fossa and large temporal lobe lesions). This is a palliative treatment to reduce symptoms

2. Multiple lesions that can be completely removed at one surgery through same incision.

3. no identifiable primary (excisional biopsy)

a. Stereotactic biopsy

i. Considered for:

1. lesions not appropriate for surgery

	a. deep lesions in eloquent cortex
	b. multiple small lesions
	c. no identified diagnosis

2. Patients not candidates for resection

	a. Poor medical condition
	b. Poor neurologic condition
	c. Active or wide-spread systemic disease

3. To ascertain diagnosis

a. When another diagnosis is possible

	i. No other sites of metastasis
	ii. Long interval between primary
	iii. If non-surgical treatment modalities are planned

Outcomes

a. With optimal treatment, median survival of patients with cerebral mets is 26-32 weeks after diagnosis.

b. By the time neurological findings develop, median survival among untreated patients ~1 month.

c. Using steroids alone doubles survival to 2 months

d. WBRT + steroids increases survival to 3-6 months

e. iv. 50% of deaths are due to progression of the intracranial disease.

f. Factors associated with better prognosis

	i. Karnofsky score >70
	ii. Age <60
	iii. Mets to brain only (no systemic mets)
	iv. Absent or controlled primary disease
	v. >1 year since primary diagnosed
	vi. female gender

g. Surgery + WBRT

i. Recurrence of tumor was significantly less frequent and more delayed with the use of post-op WBRT.

ii. There is also an additional loss of cognitive function after WBRT, and patients are rarely independent after WBRT.

iii. In 33 patients treated with surgical resection of solitary met and post-op WBRT, median survival was 8 months, with 44% 1 year survival.

1. If no evidence of systemic cancer1 year survival is 81%

2. If systemic cancer is present, whether active or inactive, 1 year survival is 20%

iv. Surgical mortality is 4% (same as 30 day mortality in the XRT group only)

v. Following surgical resection & WBRT, 22% of patients will have recurrent brain met within 1 year.

1. surgery without XRT recurrence rate is 46-85)%

Stereotactic Radiosurgery

i. Gamma Knife/Cyber Knife

ii. Advantages

	1. Can be performed on any brain location
	2. Can treat multiple tumors in one procedure
	3. Concomitant illness and Coagulopathy are not an issue

iii. Disadvantages

	1. Availability
	2. Unproven Outcome
	3. Does not reduce mass effect immediately
	4. ? effect on radio-resistant tumors
	5. Large tumors >3 cms

Summary

a. All treatment is individualized

i. Surgical resection whenever possible

1. relieves mass effect immediately

a. remember � most tumors present because of symptomatic mass effect

2. best predictable outcome

ii. XRT

	1. Fractionated Radio-therapy
	2. WBRT for SCCL

iii. Recurrence

	1. Surgical resection if possible
	2. WBRT

Currently 3 modalities of treatment that can be used in combination

Patient Reading

Diseases Treated

METASTATIC BRAIN TUMORS