Soft Tissue Sarcomas

Dr.Arun Raj B

DNB General Surgery

MIMS

Introduction

Soft tissue sarcomas are rare and unusual neoplasms

- about 1% of adult human cancers

-15% of pediatric malignancies Most commonly occur in the extremities(50%) Also common in the abdominal cavity / retro-

peritoneum, trunk/thoracic region, and head and neck

Definition

Sarcomas are malignant tumors that arise from skeletal and extra-skeletal connective tissue, mesenchymal cells including:

adipose tissue bone cartilage smooth muscle including vascular smooth muscle skeletal muscle

Etiology H/o Radiation therapy .

Lymphedema – post surgery/ radiation/ filarial

Chemical exposure Thorotrast, vinyl chloride, arsenic for hepatic

angiosarcoma

Genetic syndromes Neurofibromatosis – nerve sheath tumors Li-fraumani syndrome Familial gastrointestinal stromal tumor syndrome

– KIT mutation

Classification Soft tissue and bone

viscera (gastrointestinal, genitourinary, and gynecologic organs) nonvisceral soft tissues (muscle, tendon, adipose, pleura, and connective

tissue)

By differentiation (usually with IHC staining) adipocytic tumors fibroblastic/myofibroblastic tumors fibrohistiocytic tumors smooth muscle tumors pericytic (perivascular) tumors primitive neuroectodermal tumors (PNETs) skeletal muscle tumors vascular tumors osseous tumors tumors of uncertain differentiation

Age as factor

In childhood, embryonal rhabdomyosarcoma is most common

Synovial sarcoma is more likely to be seen in young

adults (<35 years old)

An even distribution of liposarcoma and malignant

fibrous histiocytoma as the predominant types in the

older population

Histopathology is determined by anatomic site

Common subtypes in the extremity are liposarcoma and malignant fibrous histiocytoma

In the retroperitoneal location liposarcoma and

leiomyosarcoma are the most common histotypes

In the visceral location gastrointestinal stromal tumors are found almost exclusively

Histology The biologic behavior of sarcomas is extremely variable

Histologic grade is a major prognostic determinant and is based on degree of mitosis,

cellularity, presence of necrosis, differentiation, and stromal content

Low-grade sarcomas better-differentiated, less cellular, tend to resemble the tissue of origin to some extent,

cytological abnormalities are less prominent, mitotic rate is low, Grow slower, low risk of metastasis.

Diagnosis Extremity sarcomas usually present with as a painless

mass

However, pain is noted at presentation in up to one third of patients

Delay in diagnosis is common, with the most common differential diagnosis for extremity and trunk lesions being a hematoma or a "pulled“ muscle

Physical examination- should include assessment of the size of the

mass - its relationship to neurovascular and bony

structures

INVESTIGATIONS

To obtain a tissue diagnosis

To determine the exact extent of the disease

To evaluvate metastatic disease

Biopsy

Core needle biopsy guided by palpation or by image guidance if not palpable

Excisional biopsy for superficial small lesions if needle biopsy non-diagnostic

Incision biopsy Longitudinal incision without tissue flaps with meticulous

hemostasis to prevent tumor seeding in hematomas AND NO DRAIN AND SUTURING

Send biopsy fresh and orientated

Imaging

MRI For extremity masses Gives good delineation between muscle, tumor and

blood vessels

CT for abdominal and retroperitoneal PET

May help determine high vs. low grade May be helpful in recurrences

Metastatic Workup Evaluation for sites of potential metastasis:

- Lymph node metastases occur in less than 3% of adult soft tissue sarcoma.

- For extremity lesions, the lung is the principal site for metastasis of high-grade lesions.

- For visceral lesions, the liver is the principal site.

Low-grade lesions are assumed to have a low, <15% risk of subsequent metastasis

High-grade lesions have a high, >50% risk of subsequent metastasis

Workup

Low-grade extremity lesions require a chest radiograph

High-grade lesions require a chest CT Visceral lesions should have the liver imaged

as part of the initial abdominal CT or MRI.

Staging

Staging systems focus on:

- Histologic grade of the tumor

- Size of the primary tumor

- Presence or absence of metastasis Staging systems:

- apply to risk of metastasis

- disease-specific survival

- overall survival

- almost exclusively confined to extremity lesions

Staging AJCC/UICC Staging System for Soft Tissue Sarcomas

T1: <5cm T1a: superficial to muscular fascia T1b: Deep to muscular fascia

T2: >5cm T2a: superficial to muscular fascia T2b: Deep to muscular fascia

N1: Regional nodal involvement Grading

G1: Well-differentiated G2: Moderately differentiated G3: Poorly differentiated G4: Undifferentiated

Staging

Stage IA G1,2 T1a,b N0 M0

Stage IB G2 T2a,b N0 M0

Stage IIA G3,4 T1a,b N0 M0

Stage IIB G3,4 T2a N0 M0

Stage III G3,4 T2b N0 M0

Stage IV Any G Any T N1 M1

**Does not take into account extremity vs. visceral

Staging system predicts survival and risk of metastasis, but not local recurrence

Prognostic Factors Increase risk of local recurrence

– Age > 50– Recurrent disease– Positive surgical margins– Fibrosarcoma– MPNST

Increase risk of distant metastasis– Size > 5 cm– High grade– Deep location– Recurrent disease– Leiomyosarcoma

MANAGAMENT

Concept of three dimensional clearance

MULTIDISCIPLINARY APPROACH

SURGICAL RESECTION

ADJUVANT RT

CHEMOTHERAPY

NCI Trial 1975- 1981,Rosenberg et al

43 pts Amputation Vs Limb Salvage + RTAt 9 yrs follow upRecurrence rate – 6 % Vs 19%DFS - 71% Vs 63%OS - 71% Vs 70%NIH Alert 1985 – “LSS as Standard of care”

Read the cross sectional imaging

Plan your surgery preoperativelyMagnitude of ResectionReconstructionRehabilitation

Revise the anatomy

Plastic / Vascular/Ortho help as required

Surgical Planning

Three Dimensional clearance

Frozen Section control

Mark the bed for adjuvant RT

Orient the specimen

Gross the specimen

Surgical Principles

Gross Pathology

Centripetal growth

Pseudocapsule

Compressed tumor cellsFibrovascular zone (reactive inflammatory cells)

QUALITY OF MARGINS

Barrier – Tissue that has resistance to tumor invasion

Thin Barrier

Membranous muscle fasciaAdult periosteumEpineurium Vascular sheathThin growth plate

Thick Barrier

Iliotibial bandSacral fasciaJoint capsule Periosteum of infant /

young childThick growth plate

Thin Barrier – 2 cm

Thick Barrier – 3 cm

Growth Plate – 5 cm

Normal Tissue Equivalent

Aim – Normal tissue outside the barrier

CURATIVE RESECTION MARGINS

Barrier +ve - Outside the barrier

Barrier –ve – > 5 cm margin

Adjuvant Therapy

RadiotherapyBrachy / EBRT

Chemotherapy

Adjuvant radiotherapy

Small, low grade tumors < 5cm resected with 2 cm margins may not require radiation

Adjuvant radiation should be added to the surgical resection:

- If the excision margin is close- If extra muscular involvement is present- If a local recurrence would result in the

sacrifice of a major neurovascular bundle or amputation

Improves local control but not survival

Radiotherapy

Can be given as brachy-therapy or EBRT or intra-operative RT

Brachytherapy for high grade lesions External-beam radiation therapy for large (>5 cm)

high- or low-grade lesions Intra-operative RT given in cases of retro-peritoneal

sarcomas. Can be given as pre-operative/ post-operative RT. Pre-operative preferred in head and neck

malignancy/ rest post-operative RT

Chemotherapy

Can improve local control, but not survival Doxorubicin and ifosfamide have response

rates of 20% Use only in advanced disease Combination with radiation or neoadjuvant

therapy are controversial Hyperthermic isolated limb perfusion may be

used for palliation

Metastatic disease

Lung most common site of mets, but visceral often go to liver

Median survival from development of metastatic disease is 8-12 months

Resection of pulmonary mets can give 5 year survival of 32% if all mets can be removed

>3 mets is poor prognosticator

Surgeon is an important prognostic factor

Good preop planning (no ontable surprises)

Resect , Reconstruct , Restore

Thank youThank you