Don’t forget Multiple Myeloma.
Most common types of metastasis to bone:
- Breast, 50%
- Lung, 10%
- Renal, 10%
- Thyroid 5%
- Prostate 5% (usually osteoblastic- don’t fracture as often. DDx for Paget’s.)
In a child, usually neuroblastoma.
Approximately 10% of patients have a bone lesion as the initial presentation of their cancer. In this situation, it is very important that a careful staging evaluation be performed prior to biopsy. Rougraff and associates have outlined a very simple staging strategy consisting of a chest radiograph, CT scan of the chest and abdomen, serum protein electrophoresis, and technetium bone scan. This simple protocol, along with a good physical examination, will detect the primary site of the tumor in approximately 85% of patients. It is notable that in only about 3% of patients can the primary site of the tumour be identified by reviewing the bone biopsy alone.
Most frequent bony sites for metastasis:
- Vertebra
- Pelvis
- Ribs
- Femora
- Skull
Mets distal to elbow or knee- usually lung or renal primary (have access to arterial system)
Work-up for an aggressive lesion in an older patient: (will detect primary in 85% of cases)
- Focused history and examination
- Chest Xray
- CT chest abdo and pelvis
- Bone Scan
- May be cold on bone scan: MM, thyroid, renal. They also can bleed alot.
- Serum IEPG, UA
Also need to test:
Calcium
EUC (MM causes renal failure)
LFT, FBC,
ESR CRP
?Tumour markers eg PSA/Thyroid function
When a metastatic lesion develops in a patient who has a known primary carcinoma and no previous history of mets, biopsy is indicated for re-staging and to determine suitability for chemo or radiotherapy.
Needle or trucut biopsy is generally preferred.
Mirel’s Classification CORR 1989
|
1 |
2 |
3 |
|
|
Pain |
Mild |
Moderate |
Functional |
|
Site |
UL |
LL |
NOF |
|
Type of Lesion |
Blastic |
Mixed |
Lytic |
|
Size of Lesion |
<1/3 |
1/3-2/3 |
>2/3 |
Recommend OT if 8 (33% risk of fracture in next 3 months) or more points and >3 month life expectancy.
If 7 points (1 of 41 fractured): radiotherapy and observation.
10 points- all fractured
Treatment options
Radiotherapy
- excellent for bone pain
- usual dose is same as for HO- 6-8 gray if single dose (600-800cGy) – May occasionally do longer 5-10 day course depending on size or location
Bisphosphonates (good for bone pain - don’t effect tumour growth).
Chemotherapy / Hormone therapy
Radionuclides eg Strontium-89
Surgery
Internal Fixation +/- cement
- Try for IM (intramedullary) fixation if possible with recon options
Arthroplasty
- Esp for any neck of femur fracture- from IT (intertrochanteric) region up
- Always use a long cemented implant (for radiotherapy will effect ingrowth)
Surgical wounds in sites of previous (recent or old) Radiotherapy
If less than 45G total dose - wound should heal
If >60G- wound will probably not heal.