Palliative Care: Bone Metastases

Bronwyn R. Stall and William P. O’Meara

Background

What are the top 3 sites of metastatic Dz?

Top 3 sites of metastatic Dz:

Lung
Liver
Bone

What is the route of spread of cancer cells to the bone?

Most bone mets arise from hematogenous spread of cancer cells.

What part of the skeleton is more commonly affected by bone mets: axial or appendicular?

Bone mets more commonly affect the axial rather than the appendicular skeleton.

What part of the spine is most commonly affected by bone mets?

The thoracic spine is the most common site of bone mets. (Bartels RH et al., CA Cancer J 2008)

What 5 tumors are known to stimulate osteoclast activity?

Tumors known to stimulate osteoclast activity:

Breast
Prostate
Lung
Renal
Thyroid

In decreasing order, what 5 tumors carry the highest risk of bone mets?

Top 5 tumors with regard to the risk of bone mets (in decreasing order):

Prostate
Breast
Kidney
Thyroid
Lung

What is the most common presenting Sx of bone mets?

Most pts with bone mets present with pain.

Workup/Staging

What is the workup for bone mets?

Bone met workup: H&P, characterization of pain, assessment of fracture risk, assessment for weight-−bearing bone, orthopedic consult as necessary, plain films, and bone scan

What imaging test is 1^st line in evaluating bone mets?

Initial imaging of asymptomatic bone mets usually involves a bone scan (skeletal scintigraphy). If −symptomatic, directed plain films and bone scan as well as subsequent clinically directed CT and/or MRI may be beneficial.

When may plain films be useful when evaluating bone mets?

In the setting of bone pain with a positive bone scan, plain films may show an impending fracture or a pathologic fracture.

What cancer is associated with mixed lytic and sclerotic lesions?

Breast cancer is associated with mixed sclerotic and lytic lesions.

What cancers are associated with primarily blastic lesions?

Tumors with predominantly blastic lesions:

Prostate
Small cell lung cancer
Hodgkin lymphoma

What cancers are associated with primarily lytic lesions?

Tumors with predominantly lytic lesions:

Renal cell
Melanoma
Multiple myeloma
Thyroid
Non–small cell lung cancer
Non-Hodgkin lymphoma

What imaging test can help to differentiate degenerative Dz from mets?

CT and/or MRI can help to distinguish between degenerative Dz and bone mets.

When cord compression is suspected, what imaging is indicated?

MRI of the entire spine is indicated if cord compression is suspected.

What scoring system predicts for pathologic fracture?

The Mirels scoring system is a weighted system based on a retrospective review that predicts the risk of pathologic fracture through metastatic lesions in long bones. Score ranges from 4–12. A score <7 can be treated with RT alone, while a score ≥8 requires internal fixation prior to RT. (Mirels H et al., Clin Ortho Res 1989)

What are the components of the Mirels scoring system?

The Mirels scoring system consists of 4 variables:

Site (upper extremity, lower extremity, peritrochanteric)
Pain (mild, moderate, functional)
Lesion (blastic, mixed, lytic)
Size (less than one third, one third to two thirds, or more than two thirds cortex destruction)

Each variable receives 1–3 points for a total of 4–12 points. (Mirels H et al., Clin Ortho Res 1989)

What 2 risk factors predict for pathologic fracture of the femur?

Factors predicting for pathologic fracture of the femur: