If the abnormal shadow seen on chest x-ray is in the periphery of the lung, beyond visual reach of the bronchoscope, the physician will sometimes decide that transthoracic needle biopsy is indicated.
This test is usually done under x-ray or CT scan guidance, in the radiology suite, by a radiologist.
Under local anesthesia, a needle is passed between the ribs and into the mass in the lung. A sample, taken by the needle, is sent for examination for tumor cells and for cultures for various infectious lung diseases.
Transthoracic needle biopsy can be complicated by pneumothorax (a collapse of the lung caused by leakage of air from the lung into the pleural cavity), in approximately 10 to 20% of cases, and by hemoptysis (coughing of blood) in approximately 5%.
If pneumothorax occurs, a chest tube is placed between the ribs to reexpand the lung.
Transthoracic needle biopsy is successful in diagnosis of approximately 60-75% of lung cancers, but the success rate for small tumors drops below 50%. Failure to obtain a diagnosis does not exclude a diagnosis of lung cancer.
Transthoracic needle biopsy is not indicated in all cases. It should not be ordered automatically, but with a specific reason in view.