Though many advances in their treatment have been made since their initial categorization, Pancoast tumors remain difficult to treat due to low rates of possible surgical intervention, therefore prognosis is still poor.

[2] It was not until 1924 that the tumor was described in further detail, when Henry Pancoast, a radiologist from Philadelphia, published an article in which he reported and studied many cases of apical chest tumors that all shared the same radiographic findings and associated clinical symptoms, such as pain in the upper extremity following the distribution of the eighth cervical, first and second thoracic nerve trunks, as well as "sympathetic phenomena".

The results of one of these invasions is the presentation of the Horner's syndrome, which can be seen in 15-50% of patients with severe cases when involvement of the paravertebral sympathetic chain and cervical ganglion occur.

In progressive cases, the brachial plexus is also affected, causing pain and weakness in the muscles of the arm and hand with a symptomatology typical of thoracic outlet syndrome.

This syndrome is due to involvement of brachial plexus roots and that of sympathetic fibers as they exit the cord at T1 and ascend to the superior cervical ganglion.

[11][10] Due to the location of a Pancoast tumor being in the lung, the main causes are similar to various other causes of lung cancer in general, such as: Diagnosis of a Pancoast tumor can be difficult in the early stages to the similarity of its symptoms with other conditions such as arthritis, with shoulder pain being one of the only symptoms that might indicate further imaging for a patient.

[15][10] A biopsy of the lesion is typically required in order to confirm diagnosis and to provide information regarding histology and molecular markers, which in turn allow to assess for best course of treatment.

Surgery may consist of the removal of the upper lobe of a lung together with its associated structures (subclavian artery, vein, branches of the brachial plexus, ribs and vertebral bodies), as well as mediastinal lymphadenectomy.