Bone Metastases

Bone Metastases

Cancers that originate at another site (usually breast, prostate or lung) that spread to the bone are called bone metastases

Skeleton

The bones in the spine are numbered

More Spine Anatomy

Bone cancer in the spine can create problems if the tumor compresses the spinal cord inside the neural canal

Pain symptoms are related to the spot in the spine involved

Pelvic Anatomy

ribs

spine

pelvis

femurs

Most common sites for bone

metastases

Some bone mets make the bone look too white (osteoblastic)

others make dark holes (lytic)

Lytic = black hole in the bone

Blastic = abnormal white area

An MRI may show a bone met better than a regular X-ray

Bone Scan

A nuclear medicine bone scan would show bone mets as dark areas

PET scans may show the mets very clearly

PET scans can show bone mets that are in hard to see areas like the ribs or scapula

Chemotherapy can make the bones look abnormal on a PET scan because the bone marrow is working hard to make new blood

Normal looking bones prior to chemoRx

Same patient after receiving chemo

All the bones look active (bright yellow on the scan)

This is normal and not a sign of bone cancer

PET Scans can be used to help targetthe radiation three dimensionally

PET showing the cancer pushing into the back of the right hip bone

Computer generated reconstruction showing the cancer in red and the radiation zone in orange

Bone met at L2

Radiation field

A typical course of radiation is 10 treatments ( in some cases it is necessary to go slower, 20 to 25 trips)

Side Effects of Radiation for Bone mets

•Mild fatigue

•Local skin irritation

•Lower the blood count (anemia or white count)

•The bone can temporarily get weaker before strengthening

Local Side Effects of Radiation for Bone mets

Sore throat or dry mouth

Trouble swallowing or dry cough

Loose bowels or cramps

Bladder or rectal irritation

Radiation Results

•80 - 90% of the time the symptoms improve

•Complete relief in 54%

•Most respond by 10-14 days, 70% by 2 weeks, 90% by 3 months

•55 - 70% pain benefit is sustained for life

Response of bone mets to radiation

Symptoms respond within weeks

The Xrays or scans may take months to show improvement, but eventually may come back to normal

PET showing near complete response by 4 months

2006

2009

Response to Radiation

Breast cancer metastatic to the left iliac bone, 3 years after radiation (still evidence of bone destruction on CT, but no longer hot on PET scan)

Bone Metastases to the Spine

Involved vertebrae on the left and normal on the right

Kidney cancer in the spinal vertebrae surrounding the cord, and appearance after radiation…is it possible to safely radiate further?

Combine a CT scan and linear accelerator to ultimate in targeting (IGRT) and ultimate in delivery (dynamic, helical IMRT) ability to daily adjust the beam (ART or adaptive radiotherapy)