Tumours

Question 1

most common site affected by osteosarcoma?

Answer 1

long-bone metaphyses around knee-distal femur and proximal tibia, and at proximal end of humerus

Question 2

most common age group affected by osteosarcoma?

Answer 2

those aged between 15 and 20 years

Question 3

appearance on X-ray of long bone affected by multiple myeloma?

Answer 3

moth eating- numerous lytic lesions

Question 4

red flag signs in soft tissue sarcomas?

Answer 4

lump more than 5cm
deep to fascia- doesn’t move with skin movement
enlarging
painful

Question 5

which tumours commonly metastasise to bone?

Answer 5

breast
prostate-osteoblastic lesions
kidney-high bleeding risk assoc with bony metasases
lung 
thyroid

Question 6

when should a pathological fracture resulting from a malignancy be suspected?

Answer 6

PAIN-especially before any trauma
inconsistency between resulting damage and degree of trauma
concomitant disease
abnormal X-ray

Question 7

red flag symptoms of back pain?

Answer 7

age: under 18 or over 55yrs
non mechanical back pain
thoracic pain
pain that worsens when patient supine
night pain
systemic features-fever, weight loss
history of malignancy
history of steroid use

Question 8

what approach should be taken in any case of a pathological fracture due to metastatic disease?

Answer 8

MDT approach- require input of orthopaedic surgeons, oncologists, radiologists, pathologists, nurses, palliative care team, pharmacists etc.

Question 9

complications of long bone pathological fractures?

Answer 9

slow functional recovery
implant failure
fracture non-union
blood loss
PE

all risks reduced with prophylactic fixation-e.g. use of an intramedullary BEFORE any pathological fracture occurs

Question 10

how is the risk of a pathological fracture predicted?

Answer 10

presence of significant functional pain
more than 50% destruction of cortical bone
formal staging-Mirel’s criteria
high stress anatomical regions e.g. proximal femur
osteolytic lesions

Question 11

why might embolisation be required prior to bone surgery for a metastasis?

Answer 11

some secondary disease very vascular so high bleeding risk

Question 12

bone profile components?

Answer 12

calcium, Ca2+
phosphate, PO43-
ALP
albumin-important as high proportion of calcium bound to albumin so if albumin low, total calcium may be misleading e.g. in liver cirrhosis and nephrotic syndrome.

Question 13

if a 55 yr old female was to suffer a fracture after minimal trauma, and her bone profile was found to be normal, what pathology might you expect to have predisposed her to the fracture?

Answer 13

osteoporosis

Question 14

Mirel’s criteria can be used to predict the risk of a pathological fracture to determine whether prophylactic bone fixation should occur. what are it’s components?

Answer 14

dependent on 4 features:
site of bone lesion: upper limb=1, lower limb=2, peritrochanteric=3
size of lesion: less than 1/3=1, 1/3-2/3=2, more than 2/3=3
bone lesion type: blastic=1, mixed=2, lytic=3
pain: mild=1, moderate=2, functional=3

score more than 8 suggests prophylactic fixation

Question 15

before carrying out a prophylactic fixation for a bony malignancy, why is it important to know if the malignancy is primary or secondary?

Answer 15

fixation is NOT a curative procedure for the cancer, but if a tumour was found to be primary, there may be a higher likelihood of cure so you would not want to put in an intramedullary nail which will cause the cancer to spread to involve the whole bone and reduce the ability to perform limb-salvage surgery.
a BIOPSY showing a primary bone tumour e.g. sarcoma, may benefit from neoadjuvant chemo/radiotherapy

so do NOT perform prophylactic fixation until BIOPSY confirmed primary neoplasm of bone has been ruled out

Question 16

goals of fixation in prophylaxis of pathological fractures in bony metastases?

Answer 16

maximise ability for immediate mobilisation and weight bearing
protect entire bone in setting of systemic or metastatic disease
optimise implant choice in context of patient’s overall prognosis

Question 17

fixation for femoral neck and head metastatic lesions?

Answer 17

hemiarthroplasty

Question 18

what can patients be given following prophylactic bone fixation for metastatic bone disease?

Answer 18

post-op radiotherapy:
reduce pain
slow progression
treat remaining tumour burden not removed at surgery

Question 19

most common site for all bony metastases?

Answer 19

spine

Question 20

most common site for pathologic fracture secondary to bone metastasis?

Answer 20

proximal femur

Question 21

in investigating pathological fractures, why should an X-ray of the WHOLE bone be taken?

Answer 21

malignancy may be in more than 1 location along the bone

plan for surgery-margins

Question 22

preferred biopsy in pathological fractures?

Answer 22

needle biopsy

Question 23

investigations in suspected primary bone tumour?

Answer 23

FBC-anaemia-normocyctic with BM infiltration, macrocytic with multiple myeloma-arises from blood forming cells of the BM-plasma cells, so not strictly a primary bone Ca, myeloproliferative disorders, myelodysplasia, neutrophilia, thrombocytosis-reactive secondary to malignancy
Us and Es-multiple myeloma can damage renal function, may be poor renal function with renal tumour that has metastasised to bone
PSA-rule out prostate Ca metastasis to bone
CRP-usually raised with malignancy, and ESR-part of haematology sample, usually raised in osteosarcoma, raised part. in multiple myeloma-raised levels of plasma proteins-Igs
LFTs-ensure if raised ALP not result of liver disease
clotting profile-often abnormal in malignancy, and prior to surgery
urine-Bence Jones protein-rule out multiple myeloma
bone profile-serum ALP may be raised with osteosarcoma
plain X-ray-lump, bone destruction, cortical thickening, ‘cyst’ appearance-hazy and diffuse boundary suggests invasive tumour, stippled calcification inside a vacant area is characterisitc of cartilage tumours e.g. chondrosarcoma. Ca2+ raised in multiple myeloma.
CT-assess local extent of tumour, important for deciding how much tissue would have to be removed, CT chest/abdo/pelvis for staging
MRI-assess exact location and extent of tumour, relationship to surrounding structures-look for nerve, blood vessel and muscle involvement
PET scan, isotope bone scan-use of radioactive isotope, can evaluate extent of osteosarcoma and any metastatic spread
BIOPSY-needle, although open more reliable, after imaging as biopsy can distort images. tissue may require bacteriological as well as histological examination to rule out chronic osteomyelitis which may present with pain and swelling and show metaphysis destruction and periosteal new bone formation on X-ray, without systemic disease features if suppressed by prev Abx.

Question 24

definition of a primary ‘bone’ tumour?

Answer 24

origin is mesenchymal cells

Question 25

what conditions might mimic a bone tumour?

Answer 25

haematoma stress fracture healing fracture infection-periosteal reaction on X-ray also seen with malignancy

Question 26

common bone tumour symptoms and signs?

Answer 26

pain lumpy swelling local tenderness must examine area of lymphatic drainage of a lump

Question 27

complications of tumour biopsy?

Answer 27

haemorrhage infection wound breakdown pathological fracture

Question 28

malignant bone tumour highly sensitive to radiotherapy?

Answer 28

Ewing's sarcoma-originates from endothelial cells in the BM and presents in patients commonly between 10 and 20 years of age

Question 29

define the difference between immunotherapy and chemotherapy

Answer 29

immunotherapy (biologic therapy): treatment stimulating the body's own IS to fight the cancer. uses substances made by the body or mimics them e.g. monoclonal antibodies and particular proteins*

Question 30

main complications of radiotherapy?

Answer 30

postirradiation spindle-cell sarcoma pathological fracture in WB bones general ADRs of radiotherapy-sore skin, fatigue, hair loss

Question 31

symptoms and signs of osteosarcoma?

Answer 31

PAIN-constant, worse at night, gradually increases in severity lump o/e: swelling and local tenderness palpable mass in late cases, and overlying tissues look inflamed-red, hot, swollen

Question 32

why is leukaemia NOT a primary bone Ca?

Answer 32

it is a blood Ca, originating from the blood forming cells of the BM-white blood cells

Question 33

features of osteosarcoma on imaging?

Answer 33

plain X-ray: lytic lesions, may be alternating areas of increased bone density, tends to affect long bone metaphyses around the knee and proximal humerus poorly defined tumour margins breaching of cortex, sunburst effect if streaks of new bone radiating out from cortex periosteal reaction-new bone, reactive new bone in angle between periosteum and cortex-Codman's triangle radio-isotope scan-skip lesions pulmonary CT-about 10% of pts have pulmonary metastases by time they're 1st seen-haematogenous spread

Question 34

osteosarcoma treatment?

Answer 34

multi-agent chemotherapy for 8-12 wks before surgery, then as long as tumour resectable and there are no skip lesions-skip metastases equivalent to stage III metastatic disease, carry out wide resection. can then replace that segment of bone with large bone graft or custom made implant. amputation may be more appropriate in some cases for cure or to achieve adequate local control. continue chemo for another 6-12 mnths post op if bone specimen shows marked tumour necrosis (more than 90%) highlighting response to pre op chemo. substitute different chemotherapeutic agent if response poor. may do lung wedge resection for lung metastases

Question 35

what type of osteosarcomas are most common after the age of 50 yrs?

Answer 35

paget's sarcoma-malignant transformation of paget's disease of bone

Question 36

treatment of paget's sarcoma?

Answer 36

often advanced at diagnosis with pulmonary metastases can try radical excision and chemo, but low 5 yr survival palliative radiotherapy may be preferable, espec. as chemo usually difficult as uncertain renal and cardiac function.

Question 37

when should we do a frozen section in the case of a pathological fracture?

Answer 37

if we are suspecting metastatic disease

Question 38

excision of a bone tumour would be considered if?

Answer 38

isolated primary and good prognosis- depends on grading of cells following biopsy-high grade more likely to recur and spread after surgical removal in general, low grade intracompartmental lesions (not extending into interfascial or extrafascial planes) can be treated by wide excision without exposing the tumour. high grade and confined to bone may need radical excision, with or without bone graft or prosthesis amputation may be needed if high grade with extracompartmental spread of primary malignant tumour

Question 39

RFs for osteosarcoma?

Answer 39

young age-10-20years previous radiotherapy or chemotherapy-due to treatment itself and likely gene faults producing previous Ca role in this presentation hereditary retinoblastoma-retinoblastoma tumour suppressor gene (Rb neurofibromatosis possibly* down's syndrome paget's disease in older population-paget's sarcoma parent who had rectal Ca or liver Ca

Question 40

RFs for chondrosarcoma?

Answer 40

age-older than 35-40 ( most commonly pts in their 40s and 50s) male pre-existing benign osteochondroma or chondroma hereditary multiple exostoses ollier's disease maffucci's syndrome

Question 41

RFs for Ewing's sarcoma?

Answer 41

age-young-10-20yrs congenital umbilical hernia parent who had kidney Ca 1st degree relative with melanoma or bone Ca

Question 42

2nd most common bone tumour in children?

Answer 42

Ewing's sarcoma

Question 43

sites most commonly affected by chondrosarcoma?

Answer 43

``` pelvis scapula rib cage humerus proximal femur tibia ```

Question 44

sites most commonly affected by Ewing's sarcoma?

Answer 44

``` femur pelvis tibia fibula clavicle ```

Question 45

presentation of chondrosarcoma?

Answer 45

dull ache gradually enlarging lump pathological fracture if medullary lesion

Question 46

results of imaging in chondrosarcoma?

Answer 46

plain X-ray: radiolucent area with central flecks of calcification

Question 47

treatment of chondrosarcoma?

Answer 47

usually slow growing and metastasise late, so ideal case for wide excision and prosthetic replacment amputation may be safer if not certain tumour can be removed without exposing it and causing unacceptable loss of function does NOT respond to chemo or radiotherapy

Question 48

clinical features of Ewing's sarcoma?

Answer 48

pain-often throbbing | swelling

Question 49

imaging results in Ewing's sarcoma?

Answer 49

plain X-ray: bone destruction predominantly mid diaphysis in contrast to metaphyses in osteosarcoma, may be new bone formation extending along shaft, sometimes appearing as fusiform bone layers around lesion-onion peel effect. CT and MRI-large extraosseous component radio-isotope scan-lesions elsewhere in skeleton

Question 50

what diagnosis should be excluded as rapidly as possible in Ewing's sarcoma?

Answer 50

bone INFECTION | must identify malignant cells on biospy, and make distinction between this round-cell tumour and osteosarcoma.

Question 51

treatment of Ewing's sarcoma?

Answer 51

prognosis always poor radotherapy dramatic effect on tumour, but nor much enhancement of overall survival-70% if localised, 30% if lung metastases and 20% if other bones/BM involved chemotherapy more effective-5 yr survival 50% best results with combination: pre op neoadjuvant chemo, wide excision if favourable site, or radiotherapy followed by local excision if less accessible, then further course of chemo for a year.

Question 52

if secondary bone malignancy diagnosed, what treatment could be given?

Answer 52

prophylactic fixation with an intramedullary nail | radiotherapy