TNM classifications, for example, have undergone several revisions. The current version incorporates the role of nonanatomic characteristics in cancer staging, such as primary cancer site and histologic grade. The TNM classifications have also been revised where new scientific data have suggested a need for changes. The new edition has also adopted the use of “big data” and machine-learning algorithms to determine cancer staging.
AJCC’s eighth edition of the cancer staging manual has recommended major changes in breast cancer staging. While TNM staging is still the mainstay for breast cancer staging, it has been recommended that patients receive neoadjuvant therapy. AJCC recommended adjustments to multigene panels to enhance accuracy and reduce diagnostic error. The latest AJCC staging manual is based on the TNM method. AJCC guidelines are the most widely used cancer staging system in the world.
The TNM staging system incorporates four criteria for determining the stage of cancer. The criteria include tumor size, extent of regional lymph nodes involvement, and metastasis. It also considers the number of lymph nodes collected, a factor that can impact patient survival rates. However, there are many pitfalls to using the TNM system, especially when deciding which stage to assign patients. To avoid pitfalls and biases, cancer surgeons should be careful when evaluating a patient’s stage.
TNM was revised in 2003 after AJCC and International Union Against Cancer ratified the system’s classifications. The new AJCC staging system requires an examination of fifteen lymph nodes. The location of these lymph nodes determines the cancer’s stage. AJCC cancer staging is still the gold standard for cancer diagnosis. The AJCC cancer staging system has become the standard for many physicians, but some issues remain to be addressed.
The anatomic extent of a tumor and its involvement in regional lymph nodes determine its clinical T stage. A chest CT scan is the standard method for assessing tumor size and regional lymph nodes. A tumor T2 is 3 cm or greater and involves a large bronchus. T2 patients also report a weakened airway due to atelectasis. Clinically staged patients have a higher survival rate than pathologically staged patients.
The Will Rogers phenomenon, also known as the ‘Will Rogers paradox’, is an epidemiological paradox. Named after humorist Will Rogers, this phenomenon describes the migration of cancer stages in patients. Researchers who have observed this phenomenon found that patients who were staged earlier than those in the later cohort had improved prognosis. This phenomenon has been observed in both breast cancer staging and racial differences in the incidence of cancer.
MRI has improved cancer staging. The T-staging system now mimics other bowel tumors, such as the ileum and the pancreas. The T-staging system has been remodeled to be more similar to other bowel tumors, including gastric cancer. In addition to EUS, an endoluminal MRI coil is attached to endoscopic surgery. The MRI results were shown to be more accurate than the EUS in this study.
