Pathological staging relying on the Tumour-Node-Metastasis (TNM) system is currently the primary prognostic factor for patients with CRC (Wolpin and Mayer, 2008), which is, however, not accounting for the heterogeneity of individual tumours.
As it was impossible to determine which TDT line is the primary prognostic factor for outcome based on the small size of our sample and the fact that most of the patients with favorable outcomes are common between the two groups, we decided to make a prognostic group based on the combination of blue and yellow TDT line.
A detailed melanoma staging system was developed by the American Joint Committee on Cancer (AJCC) to stratify patients into prognostic groups, taking into account the principal prognostic factors including primary tumor characteristics (such as tumor thickness, ulceration, mitotic rate) and the presence, number and size of loco-regional and distant metastases [ 5].
The type of primary studies included (prognostic factor or outcome prediction) was unclear in two-thirds of the reviews.
We identified resection of the primary tumor as a prognostic factor for OS.
Our results as well as data from literature indicate that resection of the primary tumor is a prognostic factor for survival in stage IV CRC patients.
However, when these variables were included in a multivariate analysis, resection of the primary tumor remained a prognostic factor in the CAIRO2 study and in the subgroup of patients with one metastatic site in the CAIRO study.
Using the inclusion criteria of English language, adult patients, primary article, minimum 50 patients, primary focus on prognostic factors, and mortality outcome, 104 articles were identified.
Among genes differentially expressed between CLM and primary CRC, we demonstrate overexpression of LEF1 in primary CRC to be a prognostic factor for poor survival and increased risk for liver metastasis.
In the multivariate analysis that included sex, age, baseline serum LDH, performance status, localization of metastases, localization of primary tumor, number of metastatic sites involved, and treatment arm, resection of the primary tumor remained an independent prognostic factor for median OS (P = 0.010; HR 0.73, 95% CI 0.58 0.93), but not for PFS (P = 0.130; HR 0.84, 95% CI 0.68 1.05).
Node status is still a powerful prognostic factor in primary breast cancer despite advanced molecular techniques.
