Pancoast Tumor Treatment & Management

Medical management has only a secondary role in the treatment of lung cancers. In patients with disseminated lung cancer, medical treatment is required for palliation and treatment of symptoms arising from paraneoplastic syndromes. In the last few years, reports from Japan indicate that some patients with Pancoast tumors may benefit from preoperative chemoradiotherapy.^[5]

All patients with Pancoast tumors that are directly invading the parietal pleura and chest wall should undergo surgery, provided that (1) no distant metastases are present, (2) cardiopulmonary status allows surgery, and (3) no preoperative evidence of extensive mediastinal adenopathy is present. In most patients, a complete resection is performed at surgery, with subsequent prognosis dependent on lymph node status.

Preparation of the patient

Most postoperative complications following lung resection are cardiopulmonary. These include myocardial ischemia, pulmonary emboli, and respiratory failure. To avoid these complications, patients selected for surgery are required to undergo an evaluation of pulmonary function. High-risk patients benefit from supervised pulmonary rehabilitation accompanied by bronchodilator therapy. Prophylactic heparin and antiembolic stockings are used in all patients. Preoperative nutritional status is carefully assessed in all patients because a low albumin level is correlated to a higher morbidity rate.

All patients are encouraged to stop smoking at least 2 weeks prior to surgery. Preoperative assessment of cardiac risk factors is critical when evaluating potential candidates for lung resection. Perioperative cardiac complications can be reduced preoperatively in patients at high risk by instituting better perioperative monitoring, performing a lesser procedure, or achieving medical optimization. Consider preoperative angioplasty or coronary bypass in all patients with significant coronary disease.

Irradiation

Previously, superior sulcus tumors were considered inoperable and were not often successfully palliated with irradiation alone. The best results seem to occur when the tumor and the localized adjacent area, including the superior mediastinal nodes, are preoperatively treated with 30-40 Gy of radiation administered over 2-3 weeks. The radiation field partly includes the primary tumor, adjacent mediastinum, and ipsilateral clavicular area. The purpose of the preoperative irradiation is to shrink the tumor and to temporarily block lymphatic spread.

Preoperative treatment with more than 40 Gy may lead to poor healing following surgery. An interval of 2-4 weeks after radiation therapy allows the radiation to have maximal effect. After 4 weeks, all patients are reassessed for surgery. If no distant disease spread has occurred, then surgery is offered. The tumor is then resected en bloc with the chest wall.

The presence of Horner syndrome or ipsilateral supraclavicular node involvement is not an absolute contraindication for combined preoperative radiation and surgery. In current practice, interstitial implantation of radioisotopes (brachytherapy) is performed in association with external radiation therapy.

Chemotherapy

More recent data indicate that the traditional treatment of a Pancoast tumor with local approaches (surgery, radiotherapy, or a combination of both) leads to a poor outcome because of the high rate of recurrence and the lack of systemic control. The latest studies indicate that a trimodality treatment approach may improve local control and even survival. Studies with induction chemotherapy combined with hyperfractionated accelerated radiotherapy prior to surgery may be effective in improving long-term survival and lower recurrence rates. Empirical use of preoperative chemotherapy and radiation followed by surgical resection is being used in some centers, but no standardized protocols are available.

A Pancoast tumor can be approached from an anterior or posterior incision (19). The posterior incision is made along the contour of the scapula, and the pleural cavity is entered at the third or fourth intercostal space. Dissection from below prevents injury to the subclavian vessels and the brachial plexus.

Prior to any resection, the degree of tumor invasion is assessed. The surgical technique for resection of a superior sulcus tumor is an extended en bloc resection of the chest wall, including posterior portions of the first 3 ribs, part of the upper thoracic vertebrae (including the transverse process), the intercostal nerves, the lower trunk of the brachial plexus, the stellate ganglion, and a portion of the dorsal sympathetic ganglion together with the involved lung portion. Determinants of unresectability include involvement of the subclavian artery, involvement of the vertebral body with or without cord compression, or widespread invasion of the brachial plexus.

The other approach to a Pancoast tumor is an anterior transcervical approach.^[6] Most authorities believe that injury to the subclavian vessels and the brachial plexus is much less common with this incision. With this approach, exposure of the jugular and subclavian veins is more easily accomplished and the thoracic duct is readily identified. Assessment of tumor invasion of the subclavian vessel is readily appreciated with this incision, and reconstruction of these vessels is easier. This incision is not recommended for tumors that invade the posterior aspects of the ribs and their transverse processes, the stellate ganglion and sympathetic chain, and the vertebral bodies.

After the procedure is completed, 2 large pleural tubes are placed for drainage. One tube is placed at the apex of the chest to drain any residual air; the other tube is placed in the posterior gutter to drain fluid. Fix all drainage tubes to the skin site with a suture.

Surgical principles for curative resection of a Pancoast tumor can be summarized as follows:

• Excise the entire first rib and posterior segments of the second and third ribs.
• Excise corresponding thoracic nerve roots up to the intervertebral foramen.
• Excise portions of the upper thoracic vertebrae, including the transverse process if necessary.
• Excise the lower trunk of the brachial plexus.
• Excise part of the stellate ganglion and the thoracic sympathetic chain.
• Lung resection can be by either wedge or lobectomy.
• Radical mediastinal lymph node dissection can be performed.

These patients are cared for in the ICU and are extubated. Routine care of the chest tubes is maintained. Mortality rates from this procedure are 2-5%. After arrival in the ICU, vital signs are monitored every 15-30 minutes until the patient is stable. Urinary output, chest tube drainage, and temperature are monitored hourly. Daily chest radiographs are obtained until the drainage tubes are removed.

The morbidity arising from this surgery is solely caused by the extent of chest wall and lung resection. Atelectasis is very common with this surgery and requires aggressive pulmonary toilet, incentive spirometry, and early ambulation. An adjunct to the treatment of atelectasis is bronchoscopy, which is frequently required to suction out mucous plugs and to drain secretions. Almost all patients have severe chest wall pain, and epidural anesthesia is highly recommended. Most air leaks subside within a few days, and the drainage tubes are removed.

Postoperative radiotherapy

The adjuvant role for postoperative radiotherapy in superior sulcus tumors is undetermined. Radiotherapy is not indicated for patients who undergo complete resection and have no nodal metastasis. Yet, in the past, many individuals have been treated with postoperative radiotherapy in response to an incomplete resection with residual disease. To date, postoperative radiation therapy has not been shown to improve survival in patients with cancer of the lung who have had complete surgical resection without gross or microscopic residual tumor.

Some retrospective studies show benefit for postoperative radiation therapy in patients with nodal disease; however, recent oncology trials have shown no survival benefit in patients who underwent complete resection. Note that postoperative radiotherapy does decrease the frequency of local (intrathoracic) recurrence.

Postoperative radiation therapy following immediate operation and brachytherapy has been as effective as preoperative radiation therapy and brachytherapy in achieving complete resection, locoregional control, and, ultimately, cure. No studies document the usefulness of chemotherapy in the treatment of this disease.

Primary radiation therapy

Radiation therapy is used as the sole treatment only for patients with unresectable tumors or for those who are not surgical candidates. It provides excellent pain relief, but no long-term survival occurs if the primary tumor is not controlled. The most common site of recurrence after resection is the central nervous system, especially if the primary tumor is an adenocarcinoma or large cell cancer. In these situations, prophylactic cerebral radiotherapy should be administered if local control has been achieved.

For excellent patient education resources, visit eMedicine's Procedures Center. Also, see eMedicine's patient education article Bronchoscopy.

Atelectasis is a common complication of surgery and requires aggressive pulmonary toilet.

Patients who do not have a thoracic epidural usually report significant pain and require continuous narcotics, either intravenously or in patch form.

Spinal fluid leaks occur but are rare. They usually subside with pleural drainage. If a spinal fluid leak occurs in the presence of a pneumothorax, the air may enter the spinal cord and result in meningitis, which manifests as a severe headache. If the spinal fluid leak persists, an exploratory thoracotomy is performed and a muscle flap is used to close the area.

Permanent neurologic deficits are rare. They usually result from resection of the lower trunk of the brachial plexus, but they are not incapacitating. Horner syndrome may occur from resection of the stellate ganglion and the root of C8. Deficits are usually temporary, lasting a few months. To prevent the disabling symptoms from resection of the brachial plexus, some studies indicate that neurolysis and preservation of the brachial plexus by a neurosurgeon may improve surgical outcome and postoperative symptoms.^[7]

Surgical complications can be summarized as follows:

• Mortality rate (approximately 3-5%)
• Atelectasis
• Severe chest pain
• Air leaks
• Spinal fluid leaks
• Horner syndrome
• Pain

Clinical studies demonstrate that preoperative irradiation in doses not sufficient to cause gross regression of the tumor decreases local recurrences, prevents the growth of disseminated tumor cells, and increases survival compared with irradiation or surgery alone. In the past, superior sulcus tumors were considered inoperable and incurable because of their relative inaccessibility and extensive local invasion of the thoracic inlet. However, in selected patients, recent studies show complete eradication of local growth, pain relief, and improved survival rates. Some evidence indicates that a multidisciplinary approach using neoadjuvant chemotherapy and radiation may improve the resectability. However, such an approach is also associated with increased incidence of postoperative distress syndrome.^[8]

Permanent neurologic defects resulting from resection of the lower trunk of the brachial plexus involve the distribution of the ulnar nerve but are not incapacitating. Horner syndrome and anhidrosis develop postoperatively secondary to dorsal sympathectomy. None of the defects is disabling. The 5-year survival rate after surgery is approximately 30%. Intraoperative brachytherapy has had no influence on locoregional recurrence or survival in patients with completely resected tumors. In the presence of positive mediastinal lymph nodes, the median survival rate is less than 9 months.

Adverse prognostic factors have been identified and include Horner syndrome, mediastinal adenopathy, and incomplete resection. To date, no patient with the above prognostic factors has survived for 5 years.

Significant adverse prognostic factors can be summarized as follows:

• Presence of Horner syndrome
• Involvement of mediastinal lymph nodes
• Involvement of supraclavicular lymph node
• Vertebral body invasion

Radiation therapy is recommended if patients do not have a resectable tumor identified on a CT scan. Some physicians have tried brachytherapy in patients with unresectable tumors identified intraoperatively, but outcomes have been dismal.

Palliation

Poor local control of a Pancoast tumor causes significant intractable pain. These patients die less than 2 years after diagnosis. The pain is caused by tumor invasion of the brachial plexus and nerve root compression in the intervertebral foramina, which is difficult to control.

Palliative surgery does not always provide relief from pain. However, when epidural compression is imminent, surgical maneuvers that alleviate this compression are of value. Techniques to interrupt pain pathways include cervical cordotomy, selective posterior rhizotomy, stereotactic thalamotomy, and commissural myelotomy.

Occasionally, radiotherapy is required for pain control.^[9] Radiation in doses from 40-60 Gy is administered over a period of 3 weeks, eliciting relief of pain in 90% of patients and occasionally reversing hoarseness and Horner syndrome. However, most patients die within 2 years. The most common site of metastatic disease is the brain.

Note that in various series, irrespective of local control of the tumor, a considerable number of patients died from distant metastases rather than from local disease. The microscopic presence of distant metastatic disease is not presently discernible by available conventional screening methods, perhaps suggesting that more potent chemotherapy may be necessary to control the disease.^[10]

In summary, all current data indicate that the best survival rate is obtained with preoperative chemoradiotherapy followed by surgical resection in carefully selected patients.^{[9, 11, 12, 13]} Preoperative radiotherapy followed by surgery is a reasonable alternative in some patients. Involvement of the subclavian vessels or the vertebral column is associated with poor survival after surgery.^[12] However, a few centers have obtained decent experience with better surgical approaches to these structures and have published reasonable survival rates after surgery.

Involvement of mediastinal nodes is always associated with poor outcome after resection. At the time of surgery, a complete resection of all involved structures, including a lobectomy, is recommended. To date, no data describe appropriate treatment for patients with unresectable tumors who may be curable. However, extrapolation from the data for non-Pancoast stage III non–small-cell lung cancer (NSCLC) suggests that chemoradiotherapy is the best approach. In patients whose disease is believed incurable, radiotherapy offers good palliation of pain.