AAOS Comprehensive Orthopaedic Review

Section 4 - Orthopaedic Oncology and Systemic Disease

Chapter 37. Principles of Treatment of Musculoskeletal Tumors

I. Overview

A. Biologic activity and potential morbidity

 

1. The treatment of musculoskeletal tumors is based on the biologic activity and potential morbidity of each lesion.

 

2. The important biologic aspects are the risk of local recurrence and metastasis.

 

B. Surgical margins are designed to reduce the risk of local recurrence.

 

1. Intralesional—The plane of dissection enters into the tumor.

 

2. Marginal—The plane of dissection is through the reactive zone at the edge of the tumor.

 

3. Wide—The entire tumor is removed with a cuff of normal tissue.

 

4. Radical—The entire compartment that the tumor occupies is removed.

 

C. Chemotherapy—Common mechanism is to induce programmed cell death (apoptosis). Chemotherapeutic agents achieve apoptosis in various ways:

 

1. Directly damage DNA—alkylating agents, platinum compounds, anthracyclines

 

2. Deplete cellular building blocks—antifolates, cytidine analogs, 5-fluoropyrimidines

 

3. Interfere with microtubule function—vinca alkaloids, taxanes

 

D. Radiation therapy—Mechanism is to cause DNA damage through production of free radicals.

 

*Frank J. Frassica, MD, is a consultant for or an employee for SLACK, Inc.

II. Treatment of Bone Tumors

A. Benign processes/tumors

 

1. Observation—For asymptomatic inactive lesions.

 

2. Aspiration and injection

 

a. Injection materials for unicameral bone cysts of the humerus

 

i. Methylprednisolone acetate

 

ii. Bone marrow

 

iii. Synthetic bone grafts

 

b. Eosinophilic granuloma—Injection material used is methylprednisolone acetate.

 

3. Curettage (exposing the lesion and scraping it out with hand and power tools as necessary)

 

a. The margin is always intralesional.

 

b. Hand curettage is often extended with a power burr, especially for giant cell tumor and aneurysmal bone cyst.

 

c. Surgical adjuvants are used for tumors (ie, giant cell tumor) prone to recurrence (controversial value).

 

i. Phenol

 

(a) Strong base that coagulates proteins

 

(b) Potential soft-tissue injury with spillage

 

ii. Liquid nitrogen

 

(a) Freezes up to 1 cm of tissue

 

(b) High stress-fracture rate (at least 25%)

 

d. Materials used for reconstruction of the defect

 

i. Methylmethacrylate—Often used for giant cell tumors.

 

ii. Bone graft (freeze-dried allograft, synthetic graft, autogenous graft)

 

e. Benign tumors commonly treated with curettage/grafting

 

i. Giant cell tumor

 

ii. Chondroblastoma

 

iii. Chondromyxoid fibroma

 

iv. Osteoblastoma

 

v. Aneurysmal bone cyst

 

vi. Unicameral bone cyst of the proximal femur

 

f. Benign processes occasionally treated with curettage and grafting

 

i. Enchondroma

 

ii. Unicameral bone cyst of the humerus

 

iii. Nonossifying fibroma

 

4. Resection—Removal of the bone (or a major portion) with the intent to definitively remove all tumor.

 

a. Reserved for aggressive lesions with major bone destruction, soft-tissue extension, cartilage loss, or fracture

 

b. Benign processes that are treated by resection with a marginal or intralesional margin

 

i. Osteochondroma

 

ii. Periosteal chondroma

 

c. Methods used for reconstruction of the defect

 

i. Prosthetic device

 

ii. Allograft

 

iii. Allograft-prosthetic reconstruction

 

B. Malignant bone tumors (sarcomas)

 

1. Overview

 

a. Malignant bone tumors must be removed with satisfactory margin to prevent local recurrence.

 

b. Marked propensity to recur locally if not completely removed

 

c. High risk of systemic metastases

 

2. Surgery

 

a. Limb salvage versus amputation

 

i. Limb salvage—Removal of the malignant tumor with a satisfactory margin and preservation of the limb.

 

ii. Amputation—Removal of the tumor with a wide or radical margin and removal of the extremity.

 

b. Wide resection alone, with no role for chemotherapy or radiation therapy, is the only effective modality for some tumors.

 

i. Chondrosarcoma

 

ii. Adamantinoma

 

iii. Parosteal osteosarcoma

 

iv. Low-grade intramedullary osteosarcoma

 

c. Chemotherapy

 

i. Used to kill micrometastases present in the pulmonary parenchyma and other sites

 

ii. An integral component of treatment, along with surgery, in the following malignancies:

 

(a) Osteosarcoma

 

(b) Ewing sarcoma/primitive neuroectodermal tumor

 

(c) Malignant fibrous histiocytoma

 

d. Radiation therapy—External beam irradiation can be used for definitive control of the tumor in the following primary malignant bone tumors:

 

i. Ewing sarcoma/primitive neuroectodermal tumor

 

ii. Primary lymphoma of bone

 

iii. Hemangioendothelioma

 

iv. Solitary plasmacytoma of bone



III. Treatment of Soft-Tissue Tumors

A. Treatment is based on the biologic behavior and potential morbidity after removal of individual lesions.

 

B. Benign soft-tissue tumors

 

1. Observation—For inactive latent lesions. Many subcutaneous and deep lipomas are asymptomatic and require no treatment.

 

2. Simple excision—For active lesions with minimal risk for local recurrence.

 

a. Lipoma—for symptomatic superficial or deep lesions.

 

b. Schwannoma—Careful dissection of the tumor from the nerve fibers with an intralesional or marginal margin.

 

3. Wide excision—for lesions prone to local recurrence, such as extra-abdominal desmoid tumor (a benign, aggressive tumor). Extra-abdominal desmoid tumors should be removed with a wide margin.

 

C. Malignant soft-tissue tumors

 

1. Wide resection alone—Reserved for superficial low- or high-grade sarcomas that can be removed with a sufficient cuff of normal tissue.

 

2. Wide resection and external beam irradiation

 

a. Used to minimize the risk of local failure. (Local recurrence is 5% to 10% if both wide resection and external beam irradiation are used.)

 

b. The modalities below have equivalent local control rates but differing short- and long-term morbidities.

 

i. Preoperative external beam irradiation followed by wide surgical resection

 

(a) Higher risk of wound-healing complications (often prevented by soft-tissue reconstruction at the time of resection)

 

(b) Lowest risk of long-term fibrosis

 

(c) Lower total dose of irradiation (5,200 cGy)

 

ii. Wide surgical resection with postoperative external beam irradiation

 

(a) Lowest risk of wound-healing complications

 

(b) Higher risk of long-term fibrosis

 

(c) Higher dose of irradiation (6,200 to 6,600 cGy)

 

iii. Wide surgical resection followed by brachytherapy (irradiation by radioactive seeds placed into plastic tubes implanted at the time of surgical resection)

 

(a) Advantage: delivers all the irradiation during the hospital stay

 

(b) Disadvantage: longer hospital stay



IV. Amputation

A. Amputation is sometimes indicated for malignant bone and soft-tissue tumors.

 

B. Indications for amputation

 

1. The tumor cannot be completely removed by a limb-salvage procedure.

 

2. The morbidity of the planned procedure is too high.

 

3. Limb salvage will not result in a functional limb.

 

4. The tumor continues to grow after preoperative chemotherapy or radiation.

 

5. A major neurovascular bundle is involved. (This is a relative indication.)



Top Testing Facts

1. Chemotherapy drugs induce programmed cell death (apoptosis).

 

2. Radiation therapy induces DNA damage by the creation of free radicals.

 

3. Aspiration and injection is used for selected benign bone lesions—unicameral bone cyst of the humerus (methylprednisolone, bone marrow, or synthetic graft) and eosiniphilic granuloma (methylprednisolone).

 

4. Curettage and methylmethacrylate or bone graft for reconstruction is used for most benign bone tumors—giant cell tumor, chondroblastoma, osteoblastoma, chondromyxoid fibroma, and unicameral bone cyst of the proximal femur.

 

5. Wide surgical margins alone are used for sarcomas without effective adjuvant therapy—chondrosarcoma, adamantinoma, parosteal osteosarcoma.

 

6. The major benefit of chemotherapy in osteosarcoma and Ewing sarcoma is to reduce the risk of pulmonary metastases.

 

7. Radiation can be used as the definitive method for local control of primary lymphoma of bone, solitary plasmacytoma, hemangioendothelioma of bone, and Ewing sarcoma.

 

8. Simple excision is chosen for most benign soft-tissue tumors, with the exception of desmoid tumor (requires wide margins).

 

9. Preoperative irradiation for soft-tissue sarcomas results in less fibrosis but a higher risk of early wound complications compared to postoperative irradiation.

 

10. Amputation surgery criteria: (1) an adequate surgical margin cannot be achieved, (2) the morbidity is not acceptable, (3) the resulting limb will not be functional, (4) tumor growth continues after preoperative chemotherapy or irradiation, (5) the tumor involves major neurovascular bundles.



Bibliography

Kirsch DG, Hornicek FJ: Radiation therapy for soft-tissue sarcomas, in Orthopaedic Knowledge Update: Musculoskeletal Tumors 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2007, pp 313-320.

Tuy BE: Adjuvant therapy for malignant bone tumors, in Orthopaedic Knowledge Update: Musculoskeletal Tumors 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2007, pp 205-218.