SURGICAL TREATMENT

OF

MEDIASTINAL TUMOR

BY

DR. INNOCENT KINGSLEY ASOGWA

ML - 608

USUAL LOCATION OF MEDIASTINAL LESIONS

TREATMENTOF THYMOMA

Surgery

Complete surgical resection

Median sternotomy with a vertical or submammary incision is most commonly

used

bilateral anterolateral thoracotomies with transverse sternotomy, or “clam-

shell procedure”, preferred with advanced or laterally displaced large tumors

Patients with MG and thymoma have a 56% to 78% 10-year survival rate and

a 3% recurrence rate with 4.8% (1.7% since 1980) operative mortality after

extended thymectomy

Radiation

In stage II and III invasive disease, adjuvant radiation can decrease

recurrence rates after complete surgical resection from 28% to 5%

Radiation therapy has proven beneficial in the treatment of extensive disease

CONT’D

Systemic Therapy

Steroids have been shown to be active in the management of thymomas

Both single-agent and combination therapy have demonstrated activity in the

adjuvant and neoadjuvant settings

Doxorubicin, cisplatin, ifosfamide, corticosteroids, and cyclophosphamide all

have been used as single-agent therapy

Molecularly Targeted Therapy

Overexpression of c-kit is common in thymic carcinoma

Coamplification of the HER-2/neu topoisomerase 2-alpha gene may correlate

with response to the CAP chemotherapy regimen

antitumor activity has been reported with dasatinib, a small molecule oral,

multitargeted kinase inhibitor of Bcr-Abl and src kinases, ephrin receptor

kinases, platelet-derived growth factor receptor, and c-kit, in thymoma

Branches of the internal thoracic arteries are divided to permit the en bloc specimen to be rotated upward, exposing the undersurface of the gland and the draining veins. The exposed brachiocephalic and thymic veins are isolated and divided between ligatures or clips (inset).

PREOPERATIVE

Initial workup:

careful history and physical examination the neck and particularly the thyroid gland require careful palpation

Investigation:

complete blood count,

serum electrolytes,

thyroid function tests,

acetylcholine-receptor antibody assay,

pulmonary function tests,

electromyographic studies,

immunoglobulin assay,

bone marrow biopsy,

cervical lymph node biopsy

CONT’D

Radiographic Investigation:

Plain Chest X Ray 2 plane: posteroanterior and left lateral view

CT Scan

MRI

Patient's strength and respiratory status should be optimized with the

use of pyridostigmine and immunosuppressive agents when indicated

Preoperative plasmapharesis or IV immunoglobulin therapy may be

beneficial in patients with a vital capacity of less than 2 L

POSTOPERATIVE

Usually are extubated in the OR within 30 minutes of the conclusion of

the operation

Kept in a monitored setting overnight

If the patient does not have an epidural catheter in place, parenteral

analgesia can be administered in small intermittent doses of

hydromorphone or morphine

On the morning after the operation, oral medication and a clear liquid

diet are begun and advanced as tolerated

The chest tubes are removed when no air leak or significant output is

present and the lungs are fully expanded on chest x-ray 2nd

postoperative day

CONT’D

Antibiotics and the continuous epidural infusion are discontinued, and

oral narcotic analgesics are started once the chest tubes are removed

Patients with MG are discharged when their symptoms are adequately

controlled with oral medication and they are well able to tolerate a

regular diet

Most patients are able to return to normal activity and work within 2–3

weeks after transsternal thymectomy

Tapering of medications in patients with MG begins at various times

after operation depending on the judgment of the neurologist

TREATMENT OF Substernal Goiter

CONSIDERATION FOR THORACOTOMY

Atypical anatomy

Extramediastinal extension with known malignancy

Posterior location or extension of tumor

Goiters that extend to the tracheal carina

Adherence to visceral or intrathoracic parietal pleura

CONSIDERATION FOR MEDIAN STERNOTOMY

Primary retrosternal/ectopic

goiter

Atypical anatomy

Dense adhesions from prior

surgery

Inability to deliver the gland into

the neck

Extracapsular extension or

known mediastinal malignancy

Recurrent intrathoracic goiter

Prior thyroid surgery, especially

for cancer

Goiters that extend to the

tracheal carina

Goiters that cause life-

threatening compression of

mediastinal structures

Significant intraoperative

mediastinal bleeding

Adherence to mediastinal pleura

Goiters usually can be removed via cervical incision with the use of carefulblunt finger dissection to mobilize the gland from its attachment tomediastinal structures. Most large goiters can be removed through a 2-cmcollar incision.

PREOPERATIVE

Radiographic:

Chest x-ray mediastinal mass, superior mediastinal widening, tracheal

deviation or compression

Chest CT scans define the full extent and anatomic relationships of the

substernal thyroid to surrounding structures and to facilitate preoperative

planning

serum thyroid-stimulating hormone measurement If

hyperthyroidism is present antithyroid medications and beta

blockade should be undertaken before elective resection

Pulmonary functiong testing is useful

discuss these patients with the anesthesiologist in advance of surgery

POSTOPERATIVE

Length of stay for an uncomplicated procedure is overnight

patients can be discharged uneventfully with calcium or calcitriol

supplementation

If a thoracotomy or sternotomy is required, length of stay is increased

major complications injury to the trachea, parathyroid glands, or

recurrent laryngeal nerves

The need for tracheostomy is rare

TREATMENT OF TERATOMAS

For benign tumors that are so large or with involvement of adjacent

mediastinal structures so that complete resection is impossible

partial resection (debulking) can lead to the resolution of symptoms,

frequently without relapse

Malignant teratomas chemotherapy and radiation therapy,

combined with surgical excision

Overall prognosis is poor for malignant teratomas

SEMINOMAS

Sensitive to irradiation and chemotherapy

Treatment consists of systemic and local therapy:

chemotherapy with salvage surgery

combined chemoradiotherapy

Radiation therapy may be considered for early-stage disease, but is not recommended for regional disease

Platinum-based chemotherapy is common

Occasionally, excision is possible without injury to vital structures and can be recommended

When complete resection is possible, the use of adjuvant therapy is unnecessary

MEDIASTINAL NONSEMINOMAS

Current treatment: cisplatin and etoposide-based regimens

When tumor necrosis or a benign teratoma is found during surgical

exploration after chemotherapy excellent or intermediate prognosis

LYMPHOMAS

Surgeon’s primary role is to provide sufficient tissue for diagnosis and

to assist in pathologic staging.

Thoracoscopy, mediastinoscopy, or mediastinotomy and, rarely,

thoracotomy or median sternotomy may be necessary to obtain

sufficient tissue

Lymphoblastic lymphoma occurs predominantly in children,

adolescents, and young adults and represents 60% of cases of

mediastinal non-Hodgkin’s lymphoma.

NEUROGENIC TUMORS: SCHWANNOMA / NEURILIMOMA

During resection, the intraspinal component should be removed first

via a posterior laminectomy minimizes the potential for spinal

column hematoma, cord ischemia, and paralysis

Magnetic resonance image of a neurogenic tumor with extension into the spinal canal via the foramen, which gives a typical dumbbell appearance

Approach for dumbbell tumors. A. Hemilaminectomy (black arrow). B. Resection of intraspinalcomponent of tumor prior to thoracic approach

NEUROBLASTOMAS

Therapy is determined by the stage of the disease

stage I surgical excision

stage II excision and radiation therapy

stages III and IV multimodality therapy using surgical debulking, radiation

therapy, and multiagent chemotherapy

INTERNATIONAL NEUROBLASTOMA STAGING SYSTEM

GANGLION TUMORS

Ganglioneuroblastomas composed of mature and immature ganglion cells

Treatment from surgical excision alone to various chemotherapeutic strategies, depending on:

histologic characteristics,

age at diagnosis,

stage of disease

Ganglioneuromas benign tumors originating from the sympathetic chain that are composed of ganglion cells and nerve fibers

typically present at an early age the most common neurogenic tumors occurring during childhood

usual location: paravertebral region; well encapsulated, cystic degeneration when cross-sectioned

Surgical excision is curative.

PREOPERATIVE

Initial workup:

physical examination and accurate history

Imaging

CT scan to define the morphology and location of the tumor, local invasion, bony or airway involvement

MRI to clarify the relationship of the tumor to the neural foramen and spinal canal

Laboratory test:

serum and urine free catecholamine levels

Insulin and glucose levels

Adjunctive workup:

pulmonary function test

cardiac risk stratification

POSTOPERATIVE

Patients are managed similarly to any patient who has undergone

thoracotomy or thoracoscopy

Chest drains are removed early (i.e., on the day of surgery or

postoperative day 1) based on output and reexpansion of the lung

extubated in the OR, and early mobilization is advocated

Diet may be resumed in short order as tolerated

patients with paragangliomas warrants special attention to heart rate

and blood pressure

REFERENCES

1. Sugarbaker D, Bueno R, Krasna M, Mentzer S, Zellos L. Adult Chest Surgery. McGraw Hill Professional; 2009.

2. DeVita VT, Lawrence TS, Rosenberg SA. DeVita, Hellman, and Rosenberg’s Cancer: Principles & Practice of Oncology. Lippincott Williams & Wilkins; 2008.

3. Jr CMT, Beauchamp RD, Evers BM, Mattox KL. Sabiston Textbook of Surgery: Expert Consult Premium Edition: Enhanced Online Features. 19th ed. Elsevier Health Sciences; 2012.

4. Brunicardi F, Andersen D, Billiar T, Dunn D, Hunter J, Matthews J, et al. Schwartz’s Principles of Surgery. 9th ed. McGraw-Hill Education; 2009.

5. Norton JA, Barie PS, Bollinger RR, Chang AE, M.D SFL, M.D SJM, et al. Surgery: Basic Science and Clinical Evidence. Springer; 2009.

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