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FRCR2 > sarcoma > Flashcards

sarcoma Flashcards

1
Q

What investigations / imaging should be done in suspected bone sarcoma

A

XR in two planes
MRI of whole compartment and adjacent joints
CT chest
PET-CT

Core-biopsy

Suspected Ewings - bone marrow

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2
Q

How is sarcoma divided

A

Bone - 20%
Soft tissue - 80%

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3
Q

In what part of the bone is osteosarcoma commonest
And in what sites of the body

A

Metaphysis, adjacent to growth plates

Distal femur or proximal tibia, proximal humerus

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4
Q

What mutations are commonly seen in osteosarcoma

A

TP52 & MDM2

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5
Q

What is needed before treatment for osteosarcoma

A

Fertility - consider sperm banking
GFR
Audiometry
Echo

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6
Q

What is the treatment regimen for osteosarcoma

And what chemotherapy regimen

A

Neo-adjuvant chemo - 3 cycles MAP/AP
Surgery - 2-5cm margin, and limb preservation where possible
Adjuvant chemotherapy - up to 6 cycles

If <40yrs - MAP
Methotrexate, doxorubicin and cisplatin, with macrophage stimulator mifamurtide

If >40yrs - AP
Doxorubicin and cisplatin

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7
Q

What is the advantage of NACT / adj chemotherapy for osteosarcoma

A

NACT - treats microscopic disease, facilitates surgery, allows time for prosthesis to be made. No survival advantage

Adj chemo - survival advantage

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8
Q

What histological response is positive after chemotherapy for osteosarcoma

A

High necrotic rate - >90%. A poor necrotic rate suggests treatment won’t be curative

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9
Q

When is radiotherapy indicated for osteosarcoma

And what regimen

A

Not routinely indicated as osteosarcoma is very radio-resistant

Indication:
Unresectable tumour (H&N, vertebrae and pelvis) - treat with primary RT/CRT
Post-op-RT - poor response to chemotherapy (<90%), close or positive margins

Regimen: RT +/- concurrent cisplatin.
Primary RT - 66Gy/33#
Spinal RT above L2 - 47.5/25#, due to cord tolerance
Post-op RT - 60Gy/30#

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10
Q

What volumes are included in primary RT for osteosarcoma

A

Primary RT - visible tumour on CT/MRI

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11
Q

What volumes are included for post-op RT
GTV-CTV margin
CTV-PTV margin

A

Post-op RT:
GTV – areas of risk based on pre-op imaging - reconstruct GTV on post-op planning scan
CTV – GTV +2-3cm, with inclusion of scar with 0.5-1cm margin
PTV – CTV +5-10mm

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12
Q

What dose of RT is given for whole lung RT for relapse following pulmonary metastatectomy for osteosarcoma

A

> 14yrs - 18Gy in 12#
<14yrs - 15Gy in 10#

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13
Q

How is metastatic osteosarcoma treated?

A

Depends on timing to relapse and extent
If isolated relapse, consider surgical metastatectomy, and if not suitable - RFA / SABR / cryo
If not suitable for localised treatment / disseminated disease, treat systemically

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14
Q

What systemic treatment is given 2nd and 3rd line for metastatic osteosarcoma

A

2nd line - Ifosfamide + Etoposide
3rd line - Gemcitabine + Docetaxel

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15
Q

What are poor prognostic factors for osteosarcoma

A

Raised ALP, LDH or metastases at diagnosis
Poor histological response to chemotherapy
Axial or proximal extremity tumour site
Large volume tumour
Male, >18yrs
Relapse, esp early and distant non-lung mets.

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16
Q

What mutation is commonly seen in Ewings sarcoma

A

85% have t(11;22) EWS-FLI1 translocation
10% have t(21;22) EWS-ERG translocation

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17
Q

What sites are typical for Ewings sarcoma

A

Extremity bones (50%) - femur, tibia, fibula, humerus
40% in axial skeleton - Pelvis, rib, scapula, vertebrae

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18
Q

What is the treatment regimen for Ewings sarcoma

A

NACT - VDC/IE (vincristine, doxorubicin, cyclophosphamide / ifosfamide, etoposide) - alternating every 2wks for 6wks

Followed by surgery or primary RT

Adjuvant chemotherapy - 4x VDC, followed by VC/IE alternating for four cycles

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19
Q

What are the radiotherapy indications for Ewings sarcoma

A

Primary RT - if radical surgery not feasible / too morbid

Following NACT, but before surgery - if poor response to NACT, marginal resection expected, or where a response would facilitate surgery (rib/pelvis)

Post-op RT:
Close or positive margins
Displaced pathological fracture, and not all contaminated sites removed at surgery
Poor histological response to NACT, even with negative margins
Where complete surgery is technically difficult - spine/paraspinal, rib, pelvis, H&N
Sacrum - regardless of margins or response

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20
Q

What are the RT doses for each indication for Ewings sarcoma

A

Primary RT - 55Gy/30#

Following NACT, but before surgery - 50.4/28#, or 45/25# with boost of 5.4Gy/3# if concerns about wound healing or OAR

Post-op RT: shrinking field approach - 59.4Gy/33# to tumour
Phase 1 - 54Gy/30#
Phase 2 - 5.4Gy/3# boost

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21
Q

What margins are applied to post-op RT for Ewings sarcoma

A

Post-op RT: shrinking field approach - 59.4Gy/33# to tumour
Phase 1 - 54Gy/30# - 2cm radial margin and 3-5cm sup/inf margin
Phase 2 - 5.4Gy/3# boost - 2cm radial margin and 1-2cm sup/inf

22
Q

What are poor prognostic markers in Ewings sarcoma

A

Axial location - Up to 90% DFS for peripheral tumours, and 65% for axial tumours.
Large tumour volume
Raised serum LDH
Age >15yrs
Poor histological response to pre-operative chemotherapy
Incomplete/no surgery at the primary site
Non-pulmonary mets

23
Q

What is the prognosis of Ewings sarcoma

A

If localised, 5-year survival 55-70%

If pulmonary mets - 20% 5YS, and <10% with non-pulmonary mets

24
Q

How does a chondrosarcoma behave
What mutation is commonly present
What is the treatment

A

Typically locally aggressive, rather than distant spread
IDH mutations

Treated with radical surgery, or if surgery not possible, radical RT with 60Gy/30#

25
Q

What can be the result of a transformed chondrosarcoma
How is it treated

A

Can transform / dedifferentiate into an aggressive high grade sarcoma (DCS) - commonly presents metastatic

Treated with chemotherapy as osteosarcoma (PAM / AP)
Mesenchymal variants are treated as a Ewings sarcoma

26
Q

How are chordomas treated

A

Surgery if possible, but if not resectable, with radical RT - 70Gy/35#, considering protons if clivus.

27
Q

What mutation is commonly seen in giant cell tumours of the bone

A

H3F3A mut.

28
Q

How are spindle cell sarcomas treated

A

As osteosarcoma

29
Q

What tumours does NF1 predispose to

A

Malignant peripheral nerve sheath tumours (MPNT)
Plexiform neurofibromata: 8-12% lifetime risk of malignant change
Optic gliomas
GIST

30
Q

How is a soft tissue mass best investigated

A

US, MRI
CT staging
Biopsy at specialist centre

31
Q

When can surgery alone be considered as treatment for soft tissue sarcoma

A

Small (<5 cm), low grade, and superficial to the fascia

32
Q

When is an amputation considered for a soft tissue sarcoma

A

Where radical radiotherapy would cause serious radiation-induced morbidity
Where a below knee amputation would be more functional than combined surgical and radiotherapy toxicity
Recurrent disease not suitable for local resection or adjuvant RT

33
Q

What is the benefit of radiotherapy for soft tissue sarcoma

A

No improvement in overall survival, but halves the risk of local recurrence
Pre- and post-op RT give the same outcomes, but pre-op RT has less severe side effects, but worse wound healing

34
Q

What are the advantages and disadvantages of pre-op RT for soft tissue sarcoma

A

Advantages:
Lower dose, smaller volume, can make surgery easier as tumour becomes more fibrotic.

Disadvantages:
Worse wound healing
Increases difficulty of interpreting pathology and increased risk of wound complications

35
Q

When is RT indicated for STS

A

Large tumeurs (>5cm)
Deep tumours
High grade - G3
Post-op if positive margins

Pre-op RT generally preferred to post-op

36
Q

What are the indications for pre-op RT for STS

A

To increase the likelihood of an R0 resection
Radiosensitive tumours - myxoid fibrosarcoma
For tumours that are close to, but not surrounding, the neuromuscular bundle
Where a larger post-op RT volume would cause significant late toxicity

37
Q

What is the RT dose for pre-op RT for STS
What are the planning volumes

A

50Gy/25#
GTV - tumour as seen on T1 MRI (but T2 shows oedema better)
CTV - GTV +2cm axially/radially and 5cm sup/inf, edited off bones and fascia
PTV - CTV +1cm

38
Q

Where should adjuvant RT not be given to

A

The foot - poor functional outcome

39
Q

What is the post-op RT dose for STS
How is it delivered
With what volumes / margins

A

60Gy/30#
Or 66Gy/33# if positive margins

Delivered as a shrinking field technique in two phases
Phase 1 - 50Gy/25#
Phase 2 - 10Gy/5# (negative margins) or 16Gy/8# (positive margins)

GTV reconstructed on post-op imaging
Phase 1: CTV = GTV +2cm axially and 4cm sup/inf, or scar +1cm, and including clips, scar, drain sites, edited off fascia and bone
Phase 2: GTV +2cm axially and sup/inf

PTV = CTV+1cm

40
Q

When is primary RT indicated for a STS
And to what dose

A

Head and neck sarcoma - 66Gy/33#
Retroperitoneal sarcoma - 50.4Gy/28#

41
Q

What is the first line systemic treatment for metastatic STS

A

Doxorubicin or Caelyx
Ifosfamide 2nd line

42
Q

What is the adjuvant dose for retroperitoneal sarcoma, post maximal resection with positive margins

A

50.4Gy/28#, as two phases
45Gy/25#, followed by 5.4Gy/3# boost

43
Q

What is the adjuvant RT dose to the chest wall, for phylloides tumour following mastectomy
And if pt refuses a mastectomy

A

50Gy/25#

If pt does not want a mastectomy - WLE and adj RT to the whole breast (50Gy/25#), with SIB to the tumour area to 60Gy

44
Q

What germline mutations pre-dispose to GIST
Which mutation causes insensitivity to imatinib

A

cKIT and PDGFR
PDGFR-related & SHD-deficient GISTs are imatinib resistant

45
Q

What other tumours does SHD deficiency lead to

A

Increased risk of paraganglioma or parathyroid adenoma

46
Q

Where are the majority of GISTs found

A

Stomach and small intestine

47
Q

What is the main complication of GIST

A

Bleeding and rupture

48
Q

What is the typical treatment for GIST

A

Surgical resection and adjuvant imatinib if:
Size ≥5cm, high mitotic rate >50, cKIT +ve,

49
Q

What are the side effects of imatinib

A

Oedema, rash, diarrhoea, deranged LFT

50
Q

Which sarcoma is most and least likely to spread to LNs

A

Most - angiosarcoma
Least - liposarcoma

51
Q
A

FRCR2 (38 decks)

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