Soft Tissue Sarcoma

Question 1

What aetiological factors are associated with STS?

Answer 1

Most cases sporadic
- Previous RT
- Genetics (Li Fraumeni Syndrome,…)
- Chemical exposure (PVC & angiosarcoma)
- HIV can lead to Kaposi’s Syndrome

Question 2

What are the epidemiological statistics for STS?

Answer 2

• Rare (4-5 per 100,000 in Europe)
• Can occur at any age, but most common 50-70 Yrs
• Rhabdomyosarcoma most common in childhood

Question 3

What signs and symptoms are associated with STS?

Answer 3

• Painless fixed lump under skin
• Pain may occur as size increases and nerve pain develops
• Movement of limb affected
• Abdominal pain [if stomach area]
• Cough, breathlessness [if chest area]
• Backache [retroperitoneal tumours]

Question 4

What routine investigations are performed to diagnose STS?

Answer 4

• Full clinical history [new lump? Growing?]
• Ultrasound [rule out cyst]
• MRI [as sup soft tissue defn]
• Biopsy [determine type]

Question 5

How are STSs staged?

Answer 5

TNM
T1 <= 5cm
T2 >5cm
[a=superficial b= deep]

[N & M as as usual]

Question 6

How are STSs graded?

Answer 6

3 malignancy grades based on:
- Differentiation
- Necrosis
- Mitotic rate

Each factor gives a score; Sum of the three scores determines the grade

Question 7

What are the main treatment options for STSs?

Answer 7

• Surgery main method
• RT can be given adj or neo-adj
• Chemo rare and generally reserved for metastatic disease

Question 8

What surgical method is considered the most ideal for STS?

Answer 8

Wide local excision with negative margins
Same survival rate as amputation

Question 9

Why would RT be given pre-op and post-op?

Answer 9

Pre-op:
- If wound complications likely to be manageable
- Results in lower morbidity

Post-op:
- If wound complications likely after surgery

Question 10

Dose and outcomes of pre-op RT?

Answer 10

50 Gy ; 2 Gy per #
Smaller irradiated volume
Similar local control rate
More acute wound complications

Question 11

Dose and outcomes of post-op RT?

Answer 11

60-66Gy ; 2 Gy per #
Lager irradiated volume
Similar local control rate
More long term oedema, joint stiffness, fibrosis

Question 12

What immobilisation equipment is used for RT?

Answer 12

Sarcoma board
Thermoplastic shell
Head rest

Question 13

What factors need considering when immobilising a STS patient?

Answer 13

• Tattoos in stable location (not in a swollen area)
• Take a picture for reproducibility
• Marks for lasers on the shell

Question 14

What factors are considered when planning RT for a STS patient?

Answer 14

• Spare strip of limb (<20 Gy) to avoid lymphoedema
• Minimise dose to bone and joint
• Minimise subcutaneous hotspots