2.10 Imaging for Stage III or IV Disease
2.11 Imaging the Pleura
2.10 Imaging for Stage III to IV Disease
Patients with clinically advanced lung cancer or staging systems lung cancer should have imaging of the brain with magnetic resonance imaging (MRI) or CT. MRI of the brain for the early detection of brain metastases allows for early treatment.
There is as yet no supporting evidence that PET is useful in identifying occult lung cancer metastases in patients with clinical stage IA Non-Small Cell Lung Cancer (SCLC).
Repeat imaging may be required during lung cancer staging and evaluation, or when new symptoms occur, or if there is a significant delay in beginning therapy. The optimal timing for repeat imaging is not standardized but is tailored to the individual patient.
Bone scintigraphy may be used when PET or PET/CT are not available. However, bone scintigraphy has a high ‘false-positive’ possibly due to degenerative bone disease. For the diagnosis of bone metastases, MRI has comparable accuracy to bone scintigraphy.
2.11 Imaging the Pleura
Lung cancer may involve the pleura by direct invasion or via metastases. There are also primary tumors of the pleura, most importantly, mesothelioma. However, mesothelioma has a characteristic appearance.
Evaluation of pleural disease may require several imaging methods (PET, CT, ultrasound, and / or MRI) as well as invasive biopsy procedures (thoracentesis, thoracoscopy, or pleural biopsy).
CT imaging is particularly important in evaluating lung cancer with direct extension into parietal pleura, visceral pleura or extra-pleural fat. These T2/3 tumors, they are usually operable and should be distinguished from metastatic involvement of the pleural space (M1a), which is inoperable.
Some retrospective clinical studies have shown PET to be an accurate imaging technique in the detection of pleural metastases from lung cancer.
Ultrasound may be used to assess the pleural space. Some clinical imaging studies have shown that the sensitivity of ultrasound is comparable to CT. Pleural thickening > 1 cm, pleural nodularity, and diaphragmatic thickening > 7 mm were shown to be indicative of metastatic pleural disease.
MRI may be useful when evaluating the extent of tumor invasion through muscle, nerve, and bone but has not been formally studied as a staging method for pleural involvement in lung cancer.
Bénard F, Sterman D, Smith RJ, Kaiser LR, Albelda SM, Alavi A. (1999) Prognostic value of FDG PET imaging in malignant pleural mesothelioma. Journal of Nuclear Medicine : Official Publication, Society of Nuclear Medicine [1999, 40(8):1241-1245] (Retrieved 10th April 2015): http://europepmc.org/abstract/med/10450672
Yokoi K, Kamiya N, Matsuguma H, Machida S. et al. (1999) Detection of Brain Metastasis in Potentially Operable Non-small Cell Lung Cancer: A Comparison of CT and MRI. Chest. 1999;115(3):714-719 (Retrieved 10th April 2015): http://journal.publications.chestnet.org/article.aspx?articleid=1076982
Centers for Disease Control and Prevention (CDC). Lung Cancer. Information on Lung Cancer Screening. (Retrieved 22nd Jan 2015): http://www.cdc.gov/cancer/lung/basic_info/screening.htm
Lung Health UK. Information on lung cancer tests and diagnosis. (Retrieved 22nd Jan 2015): https://www.lunghealthuk.com