Metastatic

Adult

Background

Aim 

 

The identification of skeletal metastasis & fixation prior to fracture

 

Incidence

 

50% of new cancer cases have metastasis

- 1% have pathological fracture

- increasing with more aggressive palliative care

 

Reasons to Avoid Pathological Fracture

 

Life expectancy after diagnosis

- 40% at 6/12

 

Non-operative treatment poor

- morbidity

- non-union

 

Improves survival 

- 20%

 

More difficult to manage once fractured

 

Clinical presentations

 

1.  Metastasis with unknown primary / rare

 

2.  Pathological fracture

 

3.  Metastasis with known primary / commonest

 

Indications for OT

 

1.  Life expectancy > 2/12

2.  Tolerate major OT

3.  Stable fixation possible

 

Origin

 

Bone seeking malignancies

- 80% PBL

- prostate, breast, lung

- occult metastasis usually breast & prostate

 

Also Kidney, Thyroid & GIT

- 20%

- remember the hexagon

- with malignant melanoma & lymphoma in centre

 

Site 

 

80% axial 

- earliest

 

20% appendicular 

- usually proximal especially proximal femur +++

 

Mechanism of dissemination

 

1.  Haematogenous 

 

Cells carried on fibrin raft

- multiple steps

- cross many tissue layers

- tissue preference

 

2.  Lymphatic 

- renal cell

- OS

 

3.  Direct 

- rare

 

4.  Iatrogenic

 

Bone Reponse to Tumour 

 

Lytic / Sclerotic / Mixed

 

Purely lytic

- lung 

- kidney

- breast

- thyroid

- GI

- neuroblastoma

 

Lytic Metastasis FemurLytic Metastasis Proximal Femur

 

Mixed 

- breast

- prostate

- lung

- bladder

 

Blastic

- prostate

- breast

- bladder

- GI

- lung (oat cell)

 

Neck of Femur Blastic MetastasisBlastic Metastasis Breast

 

Hip Fracture Metastatic Prostate CaHip Fracture Metastatic Prostate Ca CT

 

Bone Destruction

 

1.  Osteoclast mediated 

- 2° local factors eg TNF

 

2.  Direct destruction 

- via enzymes

 

Pain 

 

75% of metastasis

 

Cause

1.  Stimulated nerve ends by direct invasion of tissue

2.  Periosteal stretching

3.  Fractures

4.  Nerve irritation

 

X-ray

 

Need > 50% bone loss to see

 

Remember to xray entire bone

- especially NOF fracture

- need to bypass all lesions

 

Bone Scan

 

Most sensitive screen

 

Bone Scan Multiple Metastasis

 

False negative ~10% 

- Myeloma / EG / Melanoma / RCC

- overwhelm osteoblasts via Osteoblast Inhibiting Factor

 

Management

Mirels Prediction system for Pathological Fracture

 

Clin Orthop 1989 

- 38 patients treated with DXRT without surgery 

- most breast cancer

- developed scoring system

- predicts post DXRT fracture risk in preDXRT long bones

- risk of fracture within 6 months 

- irradiated without fixation

 

Four risk factors

 

                1             2             3

Site:     Upper       Lower      Peritroch

Pain:      Mild          Mod       Functional

Lesion:  Blastic      Mixed        Lytic

Size:     <1/3       1/3-2/3       >2/3

 

Score < 7 irradiate safely

- < 4% chance fracture

 

Example

- large lytic lesion in proximal femur

- will score 9 immediately

 

Metastasis Proximal Femur

 

Scores

8     - 15% chance # post DXRT

9     - 33%

10   - 82%

11   - 96%

12   - 100%

 

Mortality 

 

After pathological fracture

- lung Ca = 100% mortality 6/12

- breast Ca = 50% mortality 6/12

 

Median survival metastatic disease

- 50% survive 6/12

- 30% survive 1 year

- lung 6/12

- breast 18/12

- prostate 24/12 

 

Worse if

- hypercalcemia

- lung mets

- paraplegia 

 

Management

 

Aims

 

1. Appropriate patient selection

 

Need to live longer than time for recovery from the operation (> 2/12)

 

Poor prognosis

- lung

- visceral & bone metastasis

- short interval between diagnosis & metastasis

 

2. Reconstruct so that FWB immediately

 

Overall union rate is 35%

- <15% for lung & myeloma

 

3. Address all involved areas in the bone

 

4. DXRT post-op

- entire femur should be irradiated after reaming

- patients that have DXRT have improved function & lower re-operation rate

 

Metastasis survival predication

 

Prediction of prognosis

- score correlates to prognosis

- six parameters with a total score of 0 to 12

 

Parameters

 

General condition according to Karnofsky's performance status

2 points for 80-100%

1 point for 50-70%

0 points for 10-40%

 

No of °spinal bone mets on scan

2 points for none

1 point for 1-2

0 points for 3+

 

No of vertebral metastasis

2 points for 1

1 point for 2

0 points for 3+

 

Metastasis to the major internal organs including lungs, liver, kidney and brain

2 points for no met

1 point for operable lesion

0 points for inoperable lesion

 

Primary site

2 points for thyroid, breast, prostate & rectum

1 point for kidney & liver, uterus, bladder, gallbladder or unidentified

0 points for lung & stomach

 

Spinal Cord Palsy

2 points for Frankel E

1 point for Frankel C or D

0 points for Frankel A or B

 

Prediction

 

Average period of survival

Score of 9 to 12 > 12 /12 

Score of 6 to 8 - 3 12/ 12

Score of 0 to 5 < 3/12

 

Principles

 

Remember principles are same as normal fracture fixation

- fixation will eventually fail if fracture does not unite

 

Healing is slower than normal bone

- irradiation reduces this even more

- 50Gy >14 days after surgery doesn't produce notable increase of non-union

 

Goal is to obtain union

- avoid fracture during procedure

- preserve soft tissue envelope

- rigid internal fixation

- if large lesion >75% of cortex augment with PMMA

 

Preoperative Issues

 

Pre-op embolize vascular tumours 

- renal cell

 

Nutrition 

- consider hyperalimentation

 

Hypercalcaemia 

- from tumour / fracture / metastasis

- stones, bones, abdo moans (pancreatitis), psychic moans

- treat with bisphosphonates -> inhibit osteoclastic activity

 

High uric acid levels 

- prophylaxis against gout

 

Marrow suppression

- from chemotherapy or mets

- risk infection and excessive blood loss at time of surgery

 

DVT prophylaxis

 

DXRT

 

Post-op DXRT for local control

- start Day 14

- 30 Gy / 3000 Rads in fractionated doses

 

There is a period of transient osteoporosis after DXRT in first 2 weeks

- increased fracture risk by 25-40%

- also increased infection rate

 

Healing

 

Harrington 1986 

 

65-85% metastasis will heal with radiotherapy if no fracture

- almost normal bone structure takes 4-6/12

 

Healing of pathological fracture without fixation very poor

- non-union 65-80%

 

With prophylactic fixation & 2200 rads

- 96% remission rate (of which 26% is permanent)

- 94 % bone healing

- 86% union of pathological fracture with interlocking fixation 

 

Fixation Technique

 

Harrington 1986

- aim to span diseased segment with biomechanically strongest construct

- intramedullary best 

- prosthetic replacement has better results than ORIF

- bone grafts not effective with post-op DXRT

 

PMMA 

 

Excellent

- improved results in both animal & human studies

- increased construct strength / bending strength

- improves hardware fixation to bone / improves screw hold

- better pain relief

- immediate weight bearing

- not effected by DXRT

 

Metastasis with Unknown Primary

Likely Origin / Hexagon / PBBLTKClavicle Metastasis

 

                    Thyroid     Breast      

 

Lung           MM  Lymphoma         Kidney        

 

                    Bowel            Prostate

 

Most common site for "unknown primary" 

- lung 63%

- kidney 10%

 

Most common "known primary"

- breast and prostate

 

Plan 

 

1.  Medical History

- previous malignancy

- symptoms for most likely primaries (above)

- history smoking, coughing up blood

- breast lumps

- blood in urine

- bowel disturbance / blood

- fevers / temps / generally unwell

 

2. Physical exam

- breast in women

- prostate in men

- lymph nodes 

- thyroid in neck

- skin

 

3. Plain X-ray 

- bone involved

- any other bones with pain

- CXR

 

4.  Routine bloods

- FBC ELFT

- ESR / CRP

- TFT

- PSA

- Se electrophoresis / BJ urine

- Ca, PO4, Alk Phos

- LDH

- blood film / suspect leukaemia

 

5. Bone scan

- polyostotic / monostotic

 

Bone Scan Multiple Metastasis

 

6. CT Chest/ Abdo / Pelvis

- lung / bowel / renal

 

CT Chest Lung Cancer

 

7.  Biopsy of most accessible lesion

 

Multiple lesion

- biopsy most accessible

 

If isolated bony lesion

- need to treat as primary bone tumour

- stage locally / MRI

- consult with local orthopaedic oncology unit

- discuss biopsy procedure

 

Bone marrow biopsy

- lymphoma / myeloma

 

Seminal Paper

 

Simon et al JBJS Am 1993

- 40 patients prospective study

- allows identification of 85% 

- lab values non-specific in all cases (myeloma excluded)

- history and examination found primary in 8%

- CXR found 43% of primary

- most important finding was benefit of CT

- 75% of primary diagnosed on CT chest, abdo & pelvis

- biopsy diagnosed 8% and confirmed in 30%

 

 

 

 

Specific Management

Subcapital Femoral Neck Metastasis

 

Femoral Neck Metastasis MRIMetastasis Proximal Femur

 

Fractures

 

Principle

- do very poorly with fixation

- hemiarthroplasty or THR

- stem should be 2.5 cortical diameters beyond any area of weakness

- THR if acetabulum involved

 

Lane JBJS 1980 

- 167 patients post proximal replacement

- median life expect 5.6m

- none had mechanical complications

- all walked

 

Prosthesis

 

THR

 

Proximal femoral prosthesis

- indicated for extensive metastasis

- expensive / high dislocation rate due to loss of abductor mechanism

- hemiarthroplasty better to avoid dislocation

 

Proximal Femoral Replacement

 

Intertrochanteric Metastasis

 

Lesion only

 

Options

- either pin & plate / reconstruction nail

- depends if further lesions in femur

- augment with PMMA

 

Fracture / Very Large Lesion

- calcar replacement prosthesis

 

Intertrochanteric MetastasisIntertrochanteric Met Prosthesis

 

Subtrochanteric Metastasis

 

Subtrochanteric Metastasis FemurSubtrochanteric Metastasis and Nail0001Subtrochanteric Metastasis and Nail0002

 

Management

 

Reconstruction nail preferred

- place distal vent prior to reaming

 

Acetabular Metastasis

 

Harrington classification

 

Type I

- minor cavitary defect

- medial and superior walls intact

- standard cemented cup

 

Type II

- major deficit in medial wall

- rim intact

- wire mesh to contain cement or protrusio ring

 

Acetabular Metastasis Type IIAcetabular Metastasis Antiprotrusio Cage

 

Type III

- massive deficit in lateral wall & superior cortex

 

Metastasis Acetabulum Type III APMetastasis Acetabulum Type III LateralAcetabular Metastasis Steinman Pins

 

A.  Flexible threaded Steinmann pins & protrusio cup

- anterior column inserted antigrade through iliac crest

- posterior column inserted retrograde thru acetabulum while palpating sciatic notch & SIJ thru iliac crest incision

 

B.  Saddle prosthesis

 

Femoral Diaphysis 

 

Metastasis Femoral Shaft0002Metastasis Femoral Shaft0001

 

Management

 

IM Nail

 

Supracondylar Femur 

 

Options

- Screw plate / Blade plate

- retrograde nail  

- modular knee prosthesis

 

Metastasis Distal Femur CTRenal Met EmbolisationMetastasis Distal Femur Plate and PMMA

 

Proximal Humerus 

 

Pathological Fracture HumerusPathological Fracture Humerus Plate

 

Options

- ORIF

- tumour prosthesis

 

RCC

 

Shoulder Renal Cell CarcinomaShoulder RCC EmbolisationShoulder RCC Embolisation 2Shoulder Tumour Prosthesis

 

Humeral shaft 

 

Humeral Shaft Metastasis

 

Operative v Non operative

 

 

 

Surgical Options

- locked IM nail

- PMMA + plate (probably more secure with less pain)

 

Metastasis Humerus Plate PMMA0001Metastasis Humerus Plate PMMA0002

 

Weiss et al JBJS Br 2011

- 63 patients

- 11% reoperation rate

- good return of early function without pain

 

Dijkstra Eur J Surg Oncol 1996

- 38 cases, half IMN, half plate + cement

- higher rates of pain relief with ORIF and cement

 

Proximal tibia

 

ORIF

Paediatric

DDx

 

Leukemia 

Neuroblastoma 

Wilm's    

 

Last two usually occur in < 5 year age group

 

Bone scan is method of choice for screening for metastasis

 

Leukemia

 

Epidemiology

 

Most common form of cancer in children 30%

- ALL 5 x AML

- 3 : 100 000

 

History

 

Suspect in any child complaining of diffuse bone pain

 

Xray

 

Lytic transverse lines in epiphyses

- permeative infiltration of bone with periosteal reaction

- focal destructive lesions

- occasional diffuse sclerosis

 

Diagnosis

 

CBC

Blood smear

Bone marrow aspirate

 

Neuroblastoma

 

Background

 

Tumour of sympathetic nervous system

- arises anywhere in the sympathetic nervous system or adrenal medulla

- 10% primary site not found

- malignant small round cell tumour

 

Usually present with abdominal mass and fever

 

Xray

 

Multiple destructive lytic lesions in any part of the skeleton

- often associated with periosteal new bone

- may be permeative

- skull lesions common

 

Diagnosis

 

Elevated serum / urinary catecholamines and VMA

Bone Marrow Aspirate

 

Wilms Tumour

 

Background

 

Nephroblastoma

- arises in kidneys

- usually occurs in first 5 years of life

 

Associated with hemihypertrophy / Beckwith syndrome

 

Most present with abdominal mass

- may have abdominal pain

 

Diagnosis

 

Abdominal USS / CT

 

Management

 

Nephrectomy / chemotherapy

 

Others

 

Ewings 

Lymphoma

Osteosarcoma

Rhabdomyosarcoma

Retinoblastoma