Management of a Superior Sulcus (Pancoast) Tumor
Management of a Superior Sulcus (Pancoast) Tumor
The patient is a 74-year-old gentleman who presented with a visual disturbance and right shoulder pain. On routine chest x-ray, he was found to have a right apical lung mass.
This patient sought medical attention following an episode of transient visual loss. Upon further questioning, he admitted to a deep aching pain in his right shoulder but no arm pain or weakness. He also complained of a productive morning cough but denied hemoptysis. There was no accompanying history of dyspnea, weight loss, or fatigue. His review of systems was unremarkable.
He had been previously well, except for a past medical history of hypertension treated with amlodipine besylate and multiple skin cancers, which had been removed. The visual disturbance resolved spontaneously and was attributed to a transient ischemic attack (TIA); he was prescribed aspirin therapy. He had a 60 pack-year history of cigarette smoking but stopped 2 years ago. There was no family history of cancer.
The physical examination revealed a healthy-appearing gentleman who looked his stated age. His vital signs were normal. His Eastern Cooperative Oncology Group (ECOG) performance status was 1. Examination of his cranial nerves revealed a subtle miosis of his right pupil, but no definite ptosis or anhidrosis. No cervical or supraclavicular lymphadenopathy was evident. Dullness to percussion was noted in the apex of his right lung. His cardiac, abdominal, and musculoskeletal examinations were unremarkable. No additional neurologic findings were observed. Specifically, there was no evidence of weakness or muscle atrophy of the right arm.
The initial investigations performed at his local hospital included a chest x-ray, chest computed tomography (CT) and brain magnetic resonance imaging (MRI) scans. In addition, the patient had pulmonary function tests, which revealed a forced expiratory volume in 1 second (FEV1) of 1.92 L (58% of predicted value) and a diffusing capacity of the lung for carbon monoxide (DLCO) that was 62% of predicted.
Dr. Karen Kelly: Dr. Garg, could you please review the outside imaging studies?
Dr. Kavita Garg: The chest x-ray shows a right apical mass. This is better characterized on the subsequent chest CT, which confirms the large right upper lobe lung mass, measuring 7.5 x 6.5 x 8.0 cm and extending from the lung apex to the level of the carina (Figure 1). No enlarged hilar or mediastinal nodes are seen. Probable extension into adjacent thoracic wall is evident. No evidence of disease is appreciated in his liver, adrenal glands, or visualized bones. His brain MRI is negative for metastasis.
Dr. Kelly: What do you think is the best approach for obtaining tissue-a CT-guided needle biopsy or a bronchoscopy?
Dr. Patrick Nana-Sinkam: The utility of fiberoptic bronchoscopy depends on both location and size of the lesion. In the case of peripheral lesions such as this one, bronchoscopy has only a modest diagnostic sensitivity of 33% in lesions < 2 cm and 62% in lesions > 2 cm. However, bronchoscopy may be particularly useful for assessment of the central airways. Transthoracic needle aspiration (either CT- or ultrasound-guided) carries a much higher sensitivity (85%-95%) in larger peripheral lesions.
Dr. Kelly: A CT-guided fine-needle aspiration (FNA) was performed. Dr. Franklin, please review the biopsy result.
Dr. Wilbur Franklin: The FNA shows a poorly differentiated non-small-cell lung cancer (NSCLC).
Dr. Kelly: Dr. Garg, would this patient benefit from a positron-emission tomography (PET) scan?
Dr. Garg: Yes. This patient appears to have a localized lesion and is an ideal candidate for a PET scan to confirm or refute the staging based on CT. A recent meta-analysis of 17 studies including 883 patients compared the sensitivity and specificity of [18F]-fluorodeoxyglucose (FDG)-PET with that of CT for detecting mediastinal lymph node metastases. The sensitivity and specificity of CT for detecting mediastinal lymph
node metastases was 59% and 78%, respectively. PET performed significantly better, with a sensitivity and specificity of 83% and 92%, respectively. The performance of PET may be further improved by the use of integrated PET/CT.
FDG-PET also is important for detecting extrathoracic disease. It appears to be superior to CT for detecting adrenal or liver metastases and to bone scans for detecting bone metastases. A prospective randomized study has shown that FDG-PET staging reduced the incidence of unnecessary surgery by 25%. However, it is important to remember that inflammatory cells can also take up FDG, so PET false-positives can be seen in active inflammatory or infectious diseases.
Dr. Kelly: This patient did have a PET scan, which showed a maximal standardized uptake value (SUV) of 9.2 in the region corresponding to the lung mass. No metabolic activity was seen in the mediastinum or in extrathoracic sites. Dr. Mitchell, with a negative CT and PET scan, does the patient need a mediastinoscopy?
Dr. John Mitchell: Yes, a mediastinoscopy is appropriate. As Dr. Garg pointed out, false-negative results can occur with PET scans approximately 5% to 10% of the time. Given the patient's age, pulmonary reserve, and comorbidities of hypertension with a recent TIA, I would be hesitant to perform a resection without definitive staging to guide my decision. Of particular concern is the fact that several series of patients with superior sulcus NSCLC have shown poor survival despite surgery in the presence of mediastinal lymph node (N2) involvement.[6-8]
The long-term analysis of Intergroup trial 0319 did not show a survival benefit for the addition of surgery after neoadjvuant chemoradiation in patients with stage IIIA(pN2) NSCLC and concluded that concurrent chemoradiation is the standard of care in this situation. For this reason, detailed evaluation of the mediastinum is particularly important in this patient population, and we elected to proceed to mediastinoscopy with this gentleman. Dr. Franklin, what did the mediastinoscopy show?
Dr. Franklin: We received multiple lymph node biopsies (2R, 4R, 4L, and level 7). There was no histologic evidence of malignancy in any of the sections examined.
Dr. Kelly: That's good news. Dr. Weiss, what is the clinical stage of this patient's disease?
Dr. Glenn Weiss: On the basis of a tumor with extension to the chest wall with no evidence of nodal involvement or extrathoracic disease, this patient's tumor is clinical stage T3, N0, M0. While this had been previously classified as stage IIIA, in the new American Joint Committee on Cancer (AJCC) staging system, it has been reclassified as stage IIB with an expected 5-year survival rate of 22% following surgery.
Dr. Kelly: Dr. Solomon, what can you tell us about Pancoast tumors?
Dr. Benjamin Solomon: Pancoast tumors or tumors of the superior sulcus of the lung have been defined as apical lung tumors that involve structures of the apical chest wall above the level of the second rib. They derive their eponymous nomenclature after descriptions of their radiologic and clinical features by Dr. Henry Pancoast in 1924 and 1932.[12,13] NSCLC is the predominant cause of Pancoast tumors. However, only about 3% of all NSCLC cases involve the superior sulcus. Other primary tumors have rarely been reported as causes of Pancoast tumors, including small-cell lung cancer, carcinoid and metastatic tumor deposits, and nonmalignant conditions such as amyloidosis.
As a result of their anatomic position, these tumors cause a classic combination of symptoms that constitute Pancoast syndrome: shoulder or arm pain and Horner syndrome. Pain is the most common presenting syndrome. Typically this involves the shoulder region and radiates inferiorly down the medial (ulnar) aspect of the arm and is due to involvement of the inferior brachial plexus. In time, this can become associated with weakness of the arm and wasting of the small muscles of the hand. Pain can also occur as a result of invasion of the ribs or vertebrae. The nonspecific nature of this pain can lead to a delay in diagnosis. Horner syndrome-the triad of ptosis, miosis, and anhidrosis-arises due to involvement of sympathetic nerve fibers in the stellate ganglion.
As Dr. Mitchell pointed out, it is important to adequately stage patients with tumors of the superior sulcus. Most patients have T3 or T4 tumor. Survival has been shown to be better for T3 than T4 tumors, and mediastinal lymph node involvement is a strong, negative prognostic factor. The completeness of resection is another important prognostic factor.