Introduction
Bronchogenic
carcinoma is the most common cause of cancer death in
men and women both in the United States and worldwide
[1,121]. In the US, lung cancer accounts for 32% of
cancer deaths in men and 25% of cancer deaths in women
[2]. The annual number of deaths from lung cancer is
greater than the numbers of deaths from breast, colon,
and prostate cancers combined [167]. In 2018, cancer of
the lung or bronchus was diagnosed in an estimated
234,030 people, and 154,050 mortalities were estimated
to occur [217]. Among patients who survive one lung
cancer, there is a 2.5% annual risk of developing a
second primary lung cancer [157]. Imaging studies play a
key role in the detection, staging, and post-treatment
follow-up of patients with bronchogenic carcinoma.
For lung cancer, the strongest prognostic factor for
survival is whether the tumor can be completely
resected. Because there is significant morbidity,
mortality, and cost associated with surgery, it is
important to identify and to exclude from primary
surgical therapy those patients who will not benefit
from resection [4]. Proper staging for bronchogenic
carcinoma is essential as treatment options and patient
prognosis are directly related to the patient's stage at
presentation.
Lung cancer is staged
according to a TNM (T= primary tumor, N= regional lymph
nodes, M= distant metastasis) classification system. In
June of 1997, the American Joint Committee on Cancer and
the Union Internationale Contre le Cancer revised the
stage groupings of the TNM subsets in the International
System for Staging Lung Cancer. The revisions were made
to provide greater specificity for identifying patient
groups with similar prognoses and treatment options
based upon clinical, surgical-pathologic, and follow-up
information for 5,319 patients treated for primary lung
cancer [3]. A basic understanding of this new
classification scheme is essential for any physician
involved with the diagnosis or treatment of lung
cancer.
This course emphasizes the
radiologic findings for proper staging of bronchogenic
carcinoma based upon the revised International System
classification scheme: primary tumor, nodal status, and
metastases, -- TNM. An emphasis will be placed on
computed tomography which is presently the standard
imaging modality used for the evaluation of bronchogenic
carcinoma. The usefulness and limitations of computed
tomography will be discussed. Additional information
regarding the use of other imaging modalities in the
staging of bronchogenic carcinoma is provided for
purposes of completeness. Because radiology and computed
tomography also play a role in the diagnosis of lung
cancer, the transthoracic percutaneous biopsy is also
discussed.
|
