Applying different methods to estimate the effect of age on event-free survival of breast cancer (linear, categorization based on cutpoints, classification and regression trees, quadratic, fractional polynomial, cubic splines), Hollaender found that all methods showed a decrease in risk with increasing age up to 45 50 years [ 20].
When studying multiple cancers, the categorization becomes more complicated.
> TNM staging has generally been applied as a postoperative, histopathological grading, but the introduction of imaging techniques, particularly MRI and endoscopic ultrasound, at least in the case of rectal cancer, allows some categorization of stage preoperatively.
In addition, an essential goal for applying proteomics to study cancers is to adapt its high-throughput tools for regular use in clinical laboratories for the purpose of diagnostic and prognostic categorization of cancers, as well as in assessing various cancer therapeutic regimens.
In the new system, the first way of classification is adopted, with normal uterus being class 0, since: (1) it seems to be more reasonable to start from less affected to more affected cases and (2) the scientific society is familiar mainly with this practice followed also in the categorization of cancer, endometriosis, etc.
FCDS data quality control is excellent and includes routine inspection for duplications and accurate categorization of cancer by demographic factors.
85 Specific, factor-based categorization of cancer is limited to a handful of well characterized receptor and antigenic tests.
Since 1987, the American Joint Committee on Cancer (AJCC) and the International Union Against Cancer UICCC) have proposed a worldwide categorization of cancer staging based on localized tumor invasion depth, nodal involvement, and the status of metastasis (TNM). 1 However, a recent analysis has suggested that CRC is heterogeneous in survival patterns even within staging categories.
These results raise the possibility for a histology-independent categorization of cancers using epigenetic pathways.
The «close neighbors» gene groups can be used as prognostic descriptors for clinical end-points such as patient survival, metastases development, response to therapy, etc. Sub-categorization of cancer patients is a non-trivial problem due to high heterogeneity of expression profiles.
