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Superior sulcus tumors

Valerie W. Rusch

INTRODUCTION

Pancoast tumors, properly known as “superior sulcus non-small-cell lung carcinomas,” are particularly challenging tomanage because they invade vital structures at the thoracicinlet, including the brachial plexus, subclavian vessels, andspine. Originally described in 1924 by Henry K. Pancoast, ¹ a radiologist at the University of Pennsylvania, this subsetof non-small-cell lung carcinomas (NSCLCs) was consid-ered inoperable and thus fatal, until the late 1950s. In 1956,Chardack and MacCallum described treatment of a Pancoasttumor by en bloc resection of the right upper lobe, chest wall,and nerve roots, followed by adjuvant radiotherapy leadingto a 5-year survival. In 1961, Shaw and colleagues reported apatient who became symptom free after 30 Gy of radiother-apy and went on to a successful resection. ² This treatmentstrategy was then applied to 18 more patients with goodlocal control and long-term survival. Based on this experi-ence, the standard approach to these challenging tumorsinvolved induction radiotherapy, and en bloc resection andthis became the standard of care for Pancoast tumors overthe next 40 years. In 1994 and 2000, the largest publishedretrospective studies from Memorial Sloan Kettering CancerCenter defined negative prognostic factors including medi-astinal lymph node metastases, vertebral and subclavianvessel involvement, and incomplete resection. ³ , ⁴ Complete(R0) resection was achieved in only 64% of patients withT3N0 disease and 39% of patients with T4N0 disease, andlocoregional relapse was the most common site of tumorrecurrence. Anatomic lobectomy was associated with a betteroutcome than sublobar resection and intraoperative brachy-therapy did not enhance overall survival. This retrospectivestudy documented the results of “standard” treatment forresectable Pancoast tumors and emphasized the need fornovel therapeutic approaches.

As combined modality therapy was increasingly beingused for other locally advanced NSCLC subsets (e.g., Stage IIIA [N2] disease), induction chemoradiotherapy followedby surgical resection was studied in a large North Americanprospective multi-institutional Phase II trial (T3, T4 N0-1,M0 Pancoast tumors. ⁵ A total of 110 eligible patients receivedinduction therapy using two cycles of cisplatin and etoposidechemotherapy along with 45 Gy of concurrent radiotherapy.Patients with stable or responding disease then underwentthoracotomy and resection followed by two more cycles ofchemotherapy. Induction therapy was well tolerated, allow-ing 75% of enrolled patients to go on to thoracotomy. R0resection was achieved in 91% of T3 and 87% of T4 tumors.Approximately one-third of patients had no residual viabledisease, one-third had minimal residual microscopic disease,and one-third had gross residual tumor on final pathology.Patients who had a R0 resection experienced 53% survival at5 years and the most common sites of relapse were distantrather than locoregional. Additional studies, including a

multicenter prospective clinical trial from Japan, confirmthese results and establish induction chemoradiotherapyand surgery as standard care for resectable Pancoast tumors. ⁶

ANATOMY OF PANCOAST TUMORS

The pulmonary sulcus is defined as the posterior costoverte-bral gutter, and extends from the first rib to the diaphragm.The superior pulmonary sulcus encompasses the most api-cal aspect of the gutter. Surgical resection of superior sulcustumors requires an understanding of the complex anatomy ofthis area and of the thoracic inlet, the superior aperture of thethoracic cavity bounded by the first thoracic vertebra (T1)posteriorly, the first ribs laterally, and the superior border ofthe manubrium anteriorly.

The thoracic inlet can be separated into three compart-ments based on the insertion of the anterior and middlescalene muscles on the first rib and the posterior scalenemuscle on the second rib (see Figure 20.1). The anteriorcompartment is located in front of the anterior scalenemuscle and contains the sternocleidomastoid and omohy-oid muscles, and the subclavian and internal jugular veinsand their branches. Tumors in this location invade the firstintercostal nerve and first rib, resulting in pain in the upperand anterior chest wall. The middle compartment, locatedbetween the anterior and middle scalene muscles, includesthe subclavian artery, the trunks of the brachial plexus, andthe phrenic nerve that lies on the anterior surface of theanterior scalene muscle. Tumors found in the middle com-partment invade the anterior scalene muscle, the phrenicnerve, the subclavian artery, and the trunks of the brachialplexus and middle scalene muscle and present with signsand symptoms related to direct compression or infiltrationof the brachial plexus, such as pain and paresthesias in theulnar distribution. The posterior compartment contains thenerve roots of the brachial plexus, the stellate ganglion andthe vertebral column, the posterior aspect of the subclavianartery, the paravertebral sympathetic chain, and the prever-tebral musculature. Tumors in this area invade the transverseprocesses and vertebral bodies, as well as the spinal foramina,and are associated with Horner’s syndrome (ptosis, miosis,and anhydrosis); brachial plexopathy (weakness of the intrin-sic muscles of the hand); paralysis of the flexors of the digitsresembling a “claw hand”; and diminished sensation over themedial side of the arm, forearm, and hand (related to C8 andT1 destruction).

INITIAL ASSESSMENT

Superior sulcus masses associated with chest and arm painmay be due to other pathologic processes, including infec-tious conditions like tuberculosis or malignant disorderssuch as lymphoma, primary chest wall tumors, or metastaticdisease from other neoplasms. A diagnosis of NSCLC mustbe confirmed before starting treatment and is best obtainedby transthoracic fine needle aspiration.

The extent of disease should be evaluated before surgi-cal resection is considered. Computed tomography (CT)of the chest and upper abdomen, including the adrenals,with intravenous contrast, whole body fluorodeoxyglucosepositron emission tomography (FDG-PET), and brain mag-netic resonance imaging (MRI) should be done to excludemetastatic disease in extrathoracic sites and the mediastinum.Pancoast tumors are, by definition, at least Stage IIB lungcancers, with a significant risk of mediastinal nodal involve-ment. Further staging by endobronchial ultrasound and/or mediastinoscopy should be considered if CT or positronemission tomography suggest N2 or N3 disease.

Due to the anatomical location, MRI is essential to defin-ing tumor extent and resectability. ⁷ The brachial plexus,subclavian vessels, vertebrae, and neural foramina are bestvisualized by MRI. T1 nerve root resection is well tolerated,but resection of the C8 nerve root and lower trunk of thebrachial plexus generally leads to permanent loss of intrin-sic hand and lower arm function. Radiographic evidenceof spine involvement, or neurologic symptoms and signssuggestive of nerve root or brachial plexus pathology, neces-sitates joint evaluation of these patients by a thoracic surgeonand a spine surgeon. At Memorial Sloan Kettering, the resec-tion of Pancoast tumors is planned jointly by the thoracicsurgeon and spine neurosurgeon. ⁸

SURGICAL APPROACHES TO RESECTION

The goal of any cancer operation is complete resection ofthe tumor with pathologically negative margins (R0 resec-tion). Due to their unique location, R0 resection of Pancoasttumors is technically challenging, and includes upper lobec-tomy, involved chest wall with or without the subclavianvessels, portions of the vertebral column and T1 nerve root,and dorsal sympathetic chain. Pancoast tumors may beapproached through an extended high posterolateral thora-cotomy incision (Paulson’s incision) or through an anteriorapproach popularized by Dartevelle.

Posterior approach

The patient is positioned in the lateral decubitus position butrotated slightly anteriorly, to provide exposure to the para-vertebral region (see Figure 20.2). A standard posterolateralthoracotomy is performed in the fifth intercostal space andthe chest explored to make sure that there is no evidence ofmetastatic disease. If the tumor appears resectable, the inci-sion is extended superiorly to the base of the neck following aline midway between the spinous process and the edge of thescapula. Extension of the incision anteriorly around the ante-rior border of the scapula up toward the axilla, as originallypopularized by Masaoka and colleagues in Japan, facili-tates elevation of the scapula and enhances exposure. ⁹ Thescapula is elevated away from the chest wall with either a rib-spreading retractor (see Figure 20.3) or internal mammaryretractor with good visualization of the apex of the chest(see Figure 20.4). The scalene muscles are detached from thefirst and second ribs and the first rib exposed. Involved ribs are divided anteriorly to allow for a 4 cm margin away fromthe tumor (see Figure 20.5). Care is taken to visualize andcontrol the intercostal neurovascular bundle. To facilitate theposterior dissection, the erector spinae muscles are retractedoff the thoracic spine, allowing for visualization of the cos-tovertebral gutter. To provide an adequate posterior margin,the transverse processes and rib heads are usually resected enbloc (see Figure 20.6a and b). This approach ensures a bet-ter posterior margin of resection than does disarticulationof the rib heads from the transverse processes. Intercostalnerves are meticulously ligated before division to preventleak of cerebrospinal fluid. Bleeding near the neural foraminais carefully controlled with bipolar electrocautery. The T1nerve root is examined for tumor involvement and ligated ifnecessary. Frozen sections are used liberally during the opera-tion to determine the necessary extent of resection. After thechest wall resection is completed, the detached chest wall isallowed to fall into the chest cavity and an upper lobectomyand mediastinal lymph node dissection is completed in the standard fashion (see Figure 20.7). Reconstruction of thechest wall is not necessary unless the defect created is largerthan the first three ribs, in which case the angle of the scapulacan herniate into the chest cavity, causing pain and impairedshoulder motion. If a chest wall reconstruction is needed, a2 mm thick PTFE patch is sutured to the margins of resection.

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