Interventional Radiology in the Diagnosis and Treatment of Lung Cancer

20 INTERVENTIONAL RADIOLOGY IN THE DIAGNOSIS AND TREATMENT OF LUNG CANCER

Douglas M. Coldwell, MD, PhD • Omar Safi Zuberi, DO

A 80-year-old male developed increasing shortness of air (SOA), and a 5-cm left hilar mass is found on computed tomography (CT) compressing the central airway. He has known chronic obstructive pulmonary disease (COPD). A positron emission tomographic (PET) scan identifies SUV-positive mediastinal lymph nodes and contralateral smaller nodules. Magnetic resonance imaging (MRI) of the brain shows a 2.5-cm mass.

The patient does not wish to undergo diagnostic or therapeutic bronchoscopy. Radiation oncology is consulted and asks for a tissue diagnosis before any radiation treatment.

Learning Objectives:

1. What is the role of interventional radiology (IR) in diagnosing lung cancer?

2. Can IR treat lung cancer?

3. Can IR palliate lung cancer symptoms?

DIAGNOSTICS OF LUNG CANCER

Diagnostic radiology has been the mainstay of the diagnosis of lung cancer, with screening chest radiographs and CT. Early detection has led to initiation of therapy at a stage where the disease is still vulnerable to treatment for cure and not palliation. However, the specifics of treatment require pathologic diagnosis of tissue samples.

Interventional radiology started the fluoroscopically guided placement of small needles into both peripheral and central lesions. The first needle biopsy was reported in Germany shortly after the discovery of x-rays, but Martin and Ellis from the Memorial Hospital in New York are credited for the development of the needle aspiration technique in 1930 using an 18-gauge needle.¹ The technique did not gain traction initially because the techniques of cytologic preparation of these small tissue specimens had not been sufficiently developed. It was not until the 1950s that the tissue preparation began to be more sophisticated. With the development of cross-sectional imaging and IR in the 1960s, the use of this technique became standard practice. Today, these needles are typically 22 or 20 gauge. Fine-needle aspirates are utilized to detect the presence of metastatic disease rather than primary lung cancer. The diagnostic accuracy depends on the technique utilized and cooperation and presence of a pathology team at the time of biopsy to evaluate the adequacy of the sample for diagnosis.

The puncture site is obviously determined by the site of the tumor. The most direct and shortest distance is determined, and the skin site is sterilized and anesthetized with lidocaine. Under imaging guidance, the needle is advanced until the tip is seen to move the lesion or to move with the lesion when the fluoroscopy unit is tilted from side to side. A 20-gauge needle can be placed and a 22-gauge needle placed coaxially within it. Multiple biopsies can then be obtained with a single needle placement.

The risks of lung biopsy to the patient include bleeding if a large vessel is crossed or a smaller amount of bleeding due to the extraction of tissue. Minor hemoptysis will likely occur if the lesion becomes more indistinct in appearance. Tumor seeding of the biopsy tract is possible, but only a handful of cases have been reported. The most common and serious complication is pneumothorax, which occurs in about 30% of patients but usually resolves with the patient on oxygen in the immediate postprocedural period. However, about 2%-3% of patients require a chest tube to relieve the air collection. This tube should be placed in the mid-second or third anterior interspace. The skin is sterilized and anesthetized, and an 8-10F catheter inserted over the rib to avoid the intercostal artery lying inferior to the more superior rib. As much air as possible should be aspirated before the Heimlich valve is attached. This valve prevents air from entering through the catheter and expels any collected air on expiration. The patient is then admitted overnight, and a chest x-ray is obtained in the morning. If the pneumothorax is resolved, the Heimlich valve is closed off by a three-way stopcock, and a repeat chest x-ray is repeated in 4-6 hours. If the air does not appear on the second chest radiograph, the chest tube can be removed. If the morning chest imaging shows that the pneumothorax still is present, the catheter and valve are left in place for another 24 hours, and the process repeated.

With the advent of CT, most lung biopsies are now performed utilizing that modality. In either modality, when the needle crosses the pleura, the patient should be instructed to stop breathing so that the sharp tip of the needle does not cause a rent in the pleura and a likely subsequent pneumothorax. Utilizing either fluoroscopy or CT, the process is the same to place the needle in the lesion.

Since many lung biopsies are now being sent for genetic analysis, the sheer amount of tissue removed with a 17-gauge guiding needle and 18-gauge core biopsy needles results in a higher rate of pneumothoraces and hemorrhage. However, careful choice of patients to minimize crossing of blebs and emphysematous changes of COPD will allow the complications to be as few as possible.

The current role of IR in the diagnosis of lung cancer is that of performing biopsies of peripheral lung lesions. It is absolutely necessary for the IR to coordinate with pathology so that they can be present to determine the adequacy of the specimens. Due to current Joint Commission on the Accreditation of Hospitals rules, the interventional radiology (IR) obtaining the biopsy must be informed of the pathology so that the patient is adequately informed of the results. It is also a quality control to assess the adequacy of the biopsies and personnel (Figure 20-1).

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