Diagnostic Efficacy of PET-FDG Imaging in Solitary Pulmonary Nodules: Conclusion
Bronchoscopy with transbronchial biopsy is considered the least invasive procedure with an overall complication rate under 5 percent. Bronchoscopy is commonly performed in patients with solitary pulmonary nodules larger than 2 cm, and a diagnostic result is obtained in 40 to 80 percent of cases, depending on the size and location of the nodule. A definite diagnosis is obtained in less than 10 percent of the patients with nodules less than 2 cm in size, and a bronchoscopy is usually not done. my canadian pharmacy online
Transthoracic fine needle aspiration biopsy of the lung is generally performed for peripheral solitary pulmonary nodules. Although a diagnosis can be established in 90 to 95 percent of nodules larger than 2 cm, the yield is approximately 60 percent for malignant nodules less than 2 cm in size, and less than 20 to 30 percent for benign nodules. Fine needle aspiration biopsy of the lung is an invasive procedure that carries a 30 percent risk of pneumothorax and a 12 percent risk of hemoptysis. In most patients with malignant nodules who are suspected to have either primary lung cancer or solitary metastases, and in most patients with nonspecific diagnoses of benign nodules, a thoracotomy is ultimately required for definitive evaluation and management.
It is thus evident that there is no single “best approach” to manage all solitary pulmonary nodules. Under ideal circumstances, one would hope for prompt thoracotomy in patients with malignant pulmonary nodules with minimum preoperative invasive diagnostic procedures. On the other hand, patients with benign nodules should be spared the risk and expense of thoracotomy and other invasive diagnostic studies.
Our study demonstrates that PET-FDG imaging is highly accurate in detecting malignancy in solitary pulmonary nodules <3 cm with positive and negative predictive values of 90 percent and 89 percent, respectively. The use of this noninvasive test can have significant clinical implications in the treatment of patients with solitary pulmonary nodules and can offer several potential benefits. An abnormal PET-FDG imaging study in a patient with solitary pulmonary nodule would obviate the need for any further invasive diagnostic studies, and the patient could be directly referred for thoracotomy. Early diagnosis of malignancy is important as the 5-year survival in patients who undergo resection for malignant nodules under 3 cm in diameter is between 50 and 80 percent. Also, prethoracotomy identification of patients with high suspicion for malignancy is usually beneficial. Some patients who are reluctant to permit thoracotomy may be more agreeable if they know they have a high likelihood of a malignancy. In patients who have concurrent illness and a significantly higher surgical risk, thoracotomy may be justifiable if malignancy is first proven or strongly suspected. On the other hand, a negative PET imaging study, suggesting a benign process, could potentially save a patient from thoracotomy and other invasive diagnostic studies. This will not only eliminate the morbidity and mortality of thoracotomy, but also has the potential for significant cost savings.
In summary, PET-FDG imaging of the lung is a new noninvasive diagnostic test that is highly accurate in differentiating benign from malignant solitary pulmonary nodules. Used in the right clinical setting, PET imaging could complement CT scanning in the evaluation and treatment of patients with solitary pulmonary nodules.